[qdeck ” bold_text=”false”]
[h] IB DP Biology HL Flashcards All Topics
[q] Cell theory
[a] -All living things are composed of cells
-Cells come from preexisting cells
-Cells are smallest unit of life
[q] Challenges to cell theory: muscle fibres
[a] -They are fused cells, so they’re long and have multiple nucleus
-challenges cells are autonomous units
[q] Challenges to cell theory: Giant algae
[a] -certain species may grow large
-challenges idea cells are microscopic and larger organisms are composed of many
[q] Challenges to cell theory: aseptate fungal hyphae
[a] -filamentous hyphae that are not partitioned will have continues cytoplasm
-Challenges idea living structures are composed of discrete cells
[q] Functions of life
[a] Metabolism: living things undertake essential chemical reactions
Reproduction: Living things produce offspring
Sensitivity: living things are responsive to stimuli
Homeostasis: living things maintain a stable internal environment
Excretion: living things require the removal of waste products
Nutrition: living things exchange materials with their environment
Growth: living things can move and change shape or size
Acronym: MR SHENG
[q] Metabolic functions of paramecium and chlorella
[a] Paramecium: Heterotrophic for nutrition, engulfs food and absorbs gases through absorption, and solids are removed through anal pore, liquids through vacuole
Chlorella: autotrophic, contains chlorophyll for photosynthesis, all essential materials are both absorbed and eliminated through passive absorption
[q] Importance of surface area and volume
[a] Volume: Rate of metabolism
Surface area: rate of exchange between cell and environment
As cell grows, volume increases faster than SA
Cells therefore can’t get too big or the cell will burn more nutrients than it is taking in–cell growth limited
[q] Adaptations cells can make to maximize SA:Vol
[a] -Cells may adopt elongated or flattened shapes
-Cells may possess cellular extensions (ex: root hairs) or fold to plasma membrane
-Cells may reduce volume by including larger central vacuoles, as plant cells do
[q] Why is an intestine cell shaped like it is?
[a] Has microvilli to increase SA (allows for more material absorption)
[q] advantages and disadvantages of light and electron microscopes
[a] Light: Can view living specimens and natural colors, but lower magnification and lower resolutions
Electron: higher magnification and resolution, but can only view dead specimen and view is monochrome–false color
[q] Differences between transmission electron micrograph and a scanning electron micrograph
[a] Transmission electron microscopy (TEM) generate cross-sections through a specimen (internal image)
Scanning electron microscopy (SEM) generates a surface rendering of a specimen
[q] determining size of an image
[a] Actual size = Image size/magnification
Magnification is usually on the image
[q] How are cells organized in multicellular organisms?
[a] -Cells of the same type may group together to form tissue
-Different tissues interact to form organs
-Organs combine to form organ systems
[q] Emergent properties of cells
[a] Emergent properties are functions present in multicellular organisms that are not present in any of the individual component cells. Emergent properties arise from the interaction of individual cells to produce new functions in multicellular aggregates. An example is increased antibiotic resistance seen in biofilms
[q] cell differentiation through selective gene expression
[a] -All cells of an organism contain an identical genome
-They differentiate through the expression of some genes and not others in the genome
-Activation of certain genes by chemicals signals will cause a cell to develop differently from other cells
-Differentiation causes different cell types to become more specialized and distinct as the mature
[q] how are genes packaged in eukaryotes?
[a] -DNA in eukaryotes is packaged with proteins in the nucleus to form chromatin
-Active genes are loosely packaged in an expanded and accessible form called euchromatin
-Inactive genes are usually tightly packaged in a more condensed form called heterochromatin
-Packaging of chromatin varies between cells according to which genes are active and inactive
[q] Two qualities of Stem cells
[a] -Self renewal: Stem cells are capable of continues division
-Potency: Stem cells are capable of differentiation (are effectively unspecialized precursors)
[q] Differentiate totipotent, pluripotent, multipotent, and unipotent stem cells
[a] -Totipotent: can form any cell type AND form extra-embryotic structures (can form new organism), ex: blastocyst (baby ones)
-Pluripotent: Can form any cell type, but not extra embryotic structures, ex: embryotic stem cells (extra baby ones)
-Multipotent: can differentiate into closely related cell types, ex: hematopoietic stem cells (bone marrow) form a variety of blood cells
-Unipotent: can divide but not differentiate, ex: muscle cells can self-replicate
[q] what are the therapeutic use of stem cells
[a] -Stem cells can be used to replace damaged/diseased cells with healthy ones
-Stem cells can be harvested from embryos, umbilical cord blood or certain adult tissues like bone marrow
-Biochemical solutions are used to trigger the differentiation of stem cells
-Cells are surgically implanted into patient’s own tissue and the host immune system is suppressed to prevent rejection of cell
[q] application of stem cells to treat stargardt’s disease
[a] -Stargardt’s disease is caused by a gene mutation that impairs photoreceptor cells in the retina
-This leads to genetically inherited macular degeneration, resulting in blindness
-May be treated by replacing damaged retinal cells with healthy ones derived from stem cells
[q] Three therapeutic examples of stem cells
[a] -Replace dead nerve cells in individuals with Parkinson’s disease (Freed et al, 2001)
-Replace bone marrow in individuals with leukemia (cancer of the blood)
-Replace pancreatic beta cells in individuals with type 1 diabetes (cannot regulate blood sugar)
[q] implications of stem cell therapy using cells derived from different sources
[a] Embryo: Growth potential is high, tumor risk is high, can be generated artificially by SCNT, and requires the destruction of an embryo
Cord blood: growth potential is high, tumor risk is lower than embryo, its easily obtained and stored, but cells must be stored from birth at high cost
Adult tissue: Growth potential is low, tumor risk is lowest, difficult to obtain, invasive to extract, and may be limited in scope of application
[q] how are stem cells potentially artificially derived?
[a] -Involves the creation of embryos via therapeutic cloning, excess embryo are created in this process, raising the ethical concerns about destruction of embryos.
-Nuclear reprogramming: induce change in the gene expression profile of a cell to transform it
[q] define prokaryote
[a] A simple cell that lacks a nucleus and all membrane-bound organelles, ex: bacteria
[q] label a prokaryotic cell
[a] -The plasmid is the little clothes hanger thing
-The glycocalyx is the slime capsule
-Cell membrane is the membrane of the cell
-Nucleoid is the little bundle of things on the image that are the DNA, but not bound to a nucleus
-Cell wall is the little shadow under the membrane
-Flagellum is the little tail on the end
[q] difference between genophore and plasmid
[a] -genosphere: circular DNA molecule that contains genetic material
-Plasmids are additional autonomous DNA molecules that can be transferred via bacterial conjugation
[q] Composition of the bacterial wall
[a] The bacterial cell wall is composed of peptidoglycan
[q] Role of pili
[a] -Attachment pili allow bacteria to adhere to surfaces
-Sex pili allow bacteria to exchange genetic information (plasmids) via bacterial conjugation
[q] explain bacterial cell division
[a] -Bacterial cells divide by binary fissions (asexual reproduction)
-The circular DNA molecule is copied and then is anchored to the plasma membrane
-The DNA loops are drawn apart as the cell elongates, before dividing (cytokinesis) to form two clones
[q] Label an animal cell
[a] -Nucleus is the bigger sphere in the cell
-Nucleolus is the smaller sphere
-Rough ER is the ER closer to the nucleus
-Smoother ER is farther from the Nucleus
-Mitochondrion is the bean near the smooth ER (important for ATP production)
-Lysosome is near the golgi apparatus, and looks like a small potato
-Golgi apparatus is the big thing with the many curved lines
-Plasma membrane is on the outside of the cell
-Ribosomes are the small dots all across the cell
-Cytoskeleton /cytosol are the cytoplasm
[q] how does compartmentalization of eukaryotic cells allow for greater complexity
[a] Eukaryotic cells contain sub-cellular structures called organelles, which compartments perform specialized functions that provide eukaryotic cells with a greater level of functional complexity
[q] role of the nucleus
[a] double membrane structure that stores DNA, and is the site of transcription (RNA synthesis)
[q] Role of the nucleolus
[a] Region in the nucleus where ribosomes are assembled
[q] role of the ER (Endoplasmic reticulum)
[a] Membrane network that transports materials between organelles via vesicles
[q] role of the golgi apparatus
[a] involved in sorting, storing, modification, and exportation of secretory products of the cell
[q] role of the ribosomes
[a] responsible for protein synthesis and an be found freely within the cytosol or may be embedded in the rough ER
[q] role of the mitochondria
[a] responsible for aerobic respiration
[q] role of lysosomes
[a] responsible for the breakdown of macromolecules (digests toxic metabolites too)
[q] difference between smooth and rough ER
[a] Rough ER has ribosomes and is therefore responsible for the transport of proteins
Smooth ER is NOT embedded with ribosomes and is involved in the transport and synthesis of carbs and lipids
[q] Parts of the plant cell
[a] Nucleus is the large circle
Nucleolus is the smaller circle
Chloroplast are the things with a lot of circles in them
The central vacuole is he large space with nothing in it
The cell wall is the wall of the cell
Mitochondrion are the place near the chloroplasts where the dark reaction happens
[q] Five differences between plant and animal cells
[a] -Plants may have chloroplast, while animals dont
-Plants have cell walls while animals dont
-Plant cells have larger, central vacuole whereas animal cells have small, temporary vacuoles, if even
-Animal cells have cholesterol in their plasma membrane, plants don’t
-Plant cells store excess glucose as starch, while animals store is as glycogen
[q] State the composition of a plant cell wall
[a] the cell wall of a plant cell is composed of cellulose
[q] identify the function of chloroplast and identify where it is in the plant tissue
[a] -Chloroplast are the organelle responsible for photosynthesis
-Chloroplast are found in photosynthetic tissues
-Chloroplast are NOT found in all plant tissues (ex: root cells)
[q] differentiate between Prokaryotes and Eukaryotes
[a] -Prokaryote’s dna is naked, molecules are circular, dna is freely floating, doesn’t have organelles, ribosomes are 70S in size, reproduce by binary fission, reproduction is asexual (cells haploid) and are the smaller of the two
-Eukaryotic cells’ dna are bound to histone protein, dna molecules are linear, dna is contained within the nucleus, has membrane-bound organelles, 80S in size, may reproduce via numerous methods, reproduction can be sexual or asexual (diploid cells like ovum and sperm) and are larger than prokaryotes
[q] Identify the properties of a phospholipid
[a] Consists of:
-Phosphate head (hydrophilic = water loving)
-2x Fatty Acid (hydrophobic = hates water)
-The phosphate group is connected to the fatty acid tails via a glycerol group
[q] How are the properties of phospholipids used to maintain the structure of a cell membrane?
[a] -The phospholipids form a bilayer
-The hydrophilic phosphate face outwards into the aqueous solutions (intracellular and extracellular)
-The hydrophobic fatty acid tails face inwards and are held in place by weak hydrophobic associations
-Because the associations are weak, phospholipids are able to move within the bilayer (membrane fluidity)
[q] Explain the Davson-Danielli model
[a] -Two layers of protein flank a central phospholipid bilayer
-This model is also referred to as a “lipo-protein sandwich”
[q] Explain the Nicolson-Singer model
[a] -Transmembrane proteins are embedded within a phospholipid bilayer
-This model is referred to as the “fluid-mosaic model”
[q] How do electron micrographs support the Davison-Danielli model?
[a] -Many micrographs show a 3-layer structure: two lighter, outer layers, and a darker, inside phospholipid layer in the middle
-Although seeming like that could be right, the interpretation is often cited as incorrect
[q] Outline evidence that can falsify the Davison-Danielli and Nicolson-Singer models
[a] -Biochem. evidence: Not all membranes consist of a constant ratio of lipid:protein (precludes ‘sandwich’ model), and membrane protein vary in size and are insoluble to water (can’t form outer layer)
-Anti-body tagging: Membrane proteins are mobile and not fixed in place (do not form a static layer)
-Freezing Fracturing: fracturing the membrane reveals a rough and irregular internal surface, which are interpreted as transmembrane proteins
[q] What is membrane fluidity?
[a] -Means that the bilayer is not static and membrane components like proteins can move positions, allowing membranes to change shape
[q] Role of cholesterol in animal membranes
[a] -Reduces membrane fluidity (immobilizes phospholipids at higher temp.)
-Reduces membrane permeability (to hydrophilic ions)
-Prevents crystallization (increases flexibility at lower temps)
[q] Differentiate between integral and peripheral membrane protein
[a] -Integral are permanently attached to membrane and are typically transmembrane (go through the bilayer)
-Peripheral are temporary proteins attached by non-covalent interactions and associate with only one surface of he membrane
[q] List the functions of membrane proteins
[a] -Junctions: Serve to connect and join two cells together
-Enzymes: Fixing to membrane localizes metabolic pathways
-Transport: Responsible for facilitated diffusion and active transport
-Recognition: May function as markers for cellular identification
-Anchorage: attachment points for cytoskeleton and extracellular matrix
-Transduction: Function as receptors for peptide horomones
Acronym: JETRAT
[q] Label a cell membrane
[a] -Cholesterol: the little hexagon things in the membrane
-Integral protein: they’re transmembrane
-Peripheral protein: NOT transmembrane–looks like a clothes hanger
-Glycoprotein (receptor molecule): on the outside of the cell and has a little tail
-Phospholipid bilayer: The lipids that make up the membrane
[q] Two key qualities of plasma membranes
[a] -Semi-permeability (some things an cross the membrane, other things can’t cross)
-Selectivity (cells can control the passage of certain materials across the membrane)
[q] Passive v active transport
[a] -Passive: movement from a region of higher concentration to a region of lower concentration along a gradient, and does not require the use of ATP–ex: simple diffusion, facilitated diffusion, osmosis
-Active transport: Movement from a region of low concentration to a region of higher concentration (against the gradient) and requires the use of ATP–Ex: membrane proteins (integral) (protein pumps)
[q] Simple diffusion
[a] The net movement of particles form a region of high concentration to a region of low concentration (until equilibrium is reached)
[q] Process of facilitated diffusion
[a] -Passive transport mechanism for materials that cannot freely cross the membrane
-Large and charged substances cannot freely cross the bilayer (ions, macromolecules)
-Membrane-bound proteins help them cross (ex: channel proteins forming hydrophilic pores)
[q] Items moved by simple diffusion v facilitated transfusion
[a] -Simple diffusion: O2, CO2, lipophilic substances (ex: steroids)
-Facilitated transfusion: Ions (Sodium, potassium, etc) and macromolecules (glucose, starch, etc)
[q] how are the structures of the potassium channel helping diffusion in nerve cells
[a] -Integral proteins with a hydrophilic inner pore via which potassium ions may be transported
-Inner pore contains a selectivity fire to restrict the passage of alternative ions
-Channels adopt an open/close conformation based on membrane polarity and binding of neurotransmitters
[q] Relationship between solutes and solvents in a solution
[a] -A solute is a substance that is dissolved in a solvent
-Due to its polarity, water is often termed the ‘universal solvent’ (won’t dissolve non-polar molecules)
[q] Osmosis
[a] -Net movement of free water molecules across a semi-permeable membrane from a region of low solute concentration to a region of high-solute concentration until equilibrium is reached
[q] Hypertonic, Hypotonic, and Isotonic
[a] -Hypertonic: higher solute concentration relatively, and water flows out of the cell
-Hypotonic: low solute concentration, water flows into cell
-Isotonic: equal solute concentration, no net movement of water
[q] Osmolarity
[a] measure of solute concentration, as defined by osmol/L
[q] Why is the osmolarity of a solution affecting animal and plant cells differently
[a] -Plant cells have rigid cell walls which prevent uncontrolled osmosis
-Plant cells may swell, but they cannot burst or rupture like animal cells
-Equally, the cell membrane may shrink from the cell wall, but overall structure remains in tact
[q] difference between primary and secondary active transport
[a] -Direct: ATP hydrolysis is used to mediate transport by causing a conformational change in the protein pump (translocate molecules against gradient)
-Indirect: Transport is coupled to another molecule moving along an electrochemical gradient
[q] How do sodium-potassium pumps work?
[a] -Three sodium ions attach to intracellular binding sites on the protein pimp
-ATP hydrolysis phosphorylates the pump and changes its conformation
-Sodium ions are translocated and released from the cell, exposing extracellular binding sites from K
-Two K ions attach to these sites and the pump is dephosphorylated
-this returns the pump to its original condition
[q] Outline the role of vesicles in the transport of materials between organelles
[a] -Polypeptides destined for secretion are synthesized by ribosomes on rough ER
-They are transported to the Golgi body via vesicles (formed from ER membrane)
-Golgi body potentially sorts, stores, and modifies these secretory products
-The proteins are then transported by another vesicle to the cell membrane for secretion
-External materials can be internalized into cellular vesicles via endocytosis (for digestion by lysosome)
[q] what is endocytosis?
[a] Process by which large substances enter the cell without crossing the membrane
[q] differentiate between phagocytosis and pinocytosis
[a] -Phago: process by which solid substances are ingested (ex food particles) (usually brought to lysosome to be broken down)
-Pino: process by which liquids/solutions (dissolved substances for example) are ingested by cell (allows for quick entry in large amounts)
[q] what is exocytosis
[a] process by which large substances exit the cell without crossing the membrane. Vesicles fuse with plasma membrane, expelling heir contents into the extracellular environment. Exocytosis adds vesicular phospholipids to the ell membrane, replacing those lost via endocytosis
[q] What are the four processes needed for the spontaneous origin of life on earth
[a] -There was non-living synthesis of simple organic molecules (from primordial inorganic molecules)
-These simple organic molecules became assembled into more complex polymers
-Certain polymers formed the capacity to self replicate (enabling inheritance)
-These molecules became packaged into membranes with a distinct internal chemistry (protobionts)
[q] The Miller-Urey experiment demonstrated that
[a] -Water was boiled to vapor to reflect the high temps. common to earth’s original conditions
-The vapor was mixed with a variety of gases to create a reducing atmosphere (no o2)
-This mixture was then exposed to an electrical discharge (simulating effects of lighting as energy source)
-The mixture was then allowed to cool (concentrating components) and left for a period of one week
-Later, the condensed mixture was analyzed and found to contain traces of simple organic molecules
-Supports idea came from an intense electric impulse
[q] What are the conditions needed for non-living synthesis of organic matter (and potential location)
[a] -Conditions: reducing atmosphere (no o2), high temps (>100degreesC), or electrical discharge
-Location: Volcano, hydrothermal vent, or meteor
[q] Evidence from Pasteur’s experiment that demonstrates that abiogenesis no longer occurs
[a] -Broths stored in vessels with long tubings (swan neck ducts) that can prevent passage of dust particles
-The broths were boiled to kill any micro-organism present in the growth medium (sterilization)
-Growth only occurred in the broth if the flask was broke open, exposing the contents to contamination
-From this it was concluded that bacterial growth came from contaminants and did not spontaneously occur
[q] Two properties of RNA that allows it to play a role in life
[a] -Can self-replicate (although DNA supersedes it because double strands increase stability)
-Can act as a catalyst (although proteins supersedes it because of greater variability of subunits)
[q] Endosymbiosis and how to the evolution of eukaryotic cells
[a] -cells which lives inside another cell with mutual benefits
-Eukaryotes are believed to have evolved from early prokaryotes that were engulfed by phagocytosis
-The engulfed cell remained undigested as it contributed new functionality to the engulfing cell
-Over generations, the engulfed cell lost its independence utility and became a supplement organelle
[q] Evidence supporting endosymbiosis
[a] -Membranes: Chloroplasts/mitochondria have double membranes
-Antibiotics: Chloroplasts/mitochondria susceptible to certain antibiotics
-Division: Chloroplasts/mitochondria divide by a fission-like process
-DNA: Chloroplast/mitochondria have own circular DNA
-Ribosomes: Chloroplasts/Mitochondria have 705 ribosomes
Acronym: MAD DR
[q] Stages of the cell cycle
[a] Interphase, M phase, G0 (Gap), G1 (growth), S phase (DNA replication), G2 (Growth/proofreading), mitosis (nuclear division), Cytokinesis (cytoplasmic division)
[q] Different events that occur during interphase
[a] -DNA replication (S phase)
-Organelle duplication
-Cell growth
-Transcription/Translation
-Obtain nutrients
-Respiration (cellular)
Acronym: DOCTOR
[q] Differentiate between the three gap phases
[a] -G1: Cell growth and prepares for DNA replication (S phase)
-G2: cell finishes growing and prepares for cell division (M phase)
-G0: non-dividing, resting phase for fully differentiated cells (e.g. neurons)
[q] mitosis
[a] -The division of a nucleus to produce two genetically identical daughter cells (diploid -> diploid)
-Mitosis occurs in human body cells and result in cloned copies
[q] list the changes in DNA organization during interphase and mitosis
[a] -DNA is usually loosely packed within the nucleus as chromatin
-During mitosis, the DNA supercoils and chromatin condenses to form visible chromosomes
-Because DNA is replicated in the S phase, each chromosome is made of identical sister chromatids
[q] Stages of mitosis
[a] Prophase: Chromosomes condense (DNA supercoils). Nuclear membrane dissolves. Paired centrosomes move to opposite poles of the cell and start producing spindle fibres
Metaphase: spindle fibres connect to centromeres of chromosomes. Contraction of spindle fibres cause chromosomes to align along the middle of the cell
-Anaphase: Spindle fibres continue to contract which results in the separation of the identical sister chromatids. Each chromatid is now referred to as a chromosome. The identical chromosomes move to opposite poles
-Telophase: Chromosomes decondense. Nuclear membranes reform around the two separate sets of identical chromosomes. Cytokinesis occurs concurrently to split the cell into two
[q] Cytokinesis in plants versus animals
[a] Animals: Microtubules filaments form a ring around the cell center which then contracts. separation is centripetal because it starts at the outside and moves in.
Plants: Vesicles form in a row at the center of the cell (equatorial plane) which fuse to form an end plate. Separation is centrifugal because it starts in the center and then moves out.
[q] The four processes that involve mitosis
[a] -Tissue repair
-Organismal growth
-Asexual reproduction (ex: vegetative propagation)
-Development of an embryo
Acronym: toad
[q] Role of cyclins in the control of the cell cycle
[a] -Cyclins are a family of regulatory proteins that control progression of cell cycle
-Cyclins bind to cyclin dependent kinases (CDKs) and form an activated complex
-This complex phosphorylates proteins involved in specific cell cycle events
-After the event has occurred, the cyclin is degraded and CDKs rendered inactive
[q] Compare apoptosis and necrosis
[a] -Apoptosis: programmed cell death (cell suicide). Involves cellular signals and mitochondrial proteins. Membrane bulges and contents are then repackaged for recycling to other cells.
-Necrosis: Uncontrolled cell death (ie homicide). Premature death of cell due to injury of trauma. Membrane destabilizes, leading to cell lysis. Released cell contents trigger inflammation.
[q] define cancer
[a] uncontrolled cell proliferation
[q] distinguish between primary and secondary tumors
[a] -Benign tumors that remains in its original location is called a primary tumor
-A tumor that spreads is a secondary tumor
[q] Role of mutagens and oncogenes in development of cancer
[a] -A mutagen is an agent that causes a change in the genetic material of an organism
-Chemicals in ciggs may cause cancer as an example
-An oncogene is a gene that has the potential to cause cancer
-proto-oncogenes code for proteins that promote cell growth and proliferation
-tumor suppressor gene code for protein that repress cell cycle progression
[q] Metabolism
[a] -Totality of all enzyme-catalyzed reactions in a cell or organism
[q] Anabolism
[a] -The build up of complex molecules from more simple subunits (monomers).
-Requires condensation reactions to proceed (water is produced as a by-product).
-Ex: photosynthesis
[q] Catabolism
[a] -The break down of complex molecules into simple subunits (monomers)
-Requires hydrolysis reactions to proceed (water consumed as part of the reaction)
–Ex: cell respiration
[q] Organic v inorganic compounds
[a] -Organic molecules contain carbon and are synthesized by living organisms (everything else is inorganic)
-Exceptions include carbides, carbonates, oxides of carbon and cyanides
[q]
How does the structure of carbon atoms contribute to the formation of organic life?
[a] -Carbon forms the base of organic life because of its capacity to form large molecules
-Carbon has four valence electrons and can form 4 covalent bond
-Allows for it to be a stable backbone in a large variety of compounds
[q] Theory of vitalism and how it was falsified
[a] -Vitalism proposed that organic molecules could ONLY be synthesized by living organisms
-Fredrick Woehler falsified it in 1828
-He was able to synthesize urea from an inorganic salt under lab conditions
[q] Monomer
[a] A recurring subunit within a more complex polymer
[q] Carbohydrates
[a] Monomer: Monosaccharide
Polymer: polysaccharide
Bond involved: Glyosidic linkage
[q] Lipid
[a] Monomer: Glycerol + fatty acids (x3)
Polymer: Triglyceride
Bond involved: Ester linkage
[q] Protein
[a] Monomer: Amino acid
Polymer: polypeptide
Bond involved: peptide band
[q] Nucleic acid
[a] Monomer: Nucleotide
Polymer: DNA or RNA
Bond involved: Phosphodiester bond
[q] Chemical formula for an unsaturated fatty acid
[a] CH3 – (CH2)n – COOH
[q] How are different biomacromolecules identified through their chem. formulas?
[a] -Carbs: Have C,H,O in a common ratio according to formula (CH2O)n
-Protein: May contain Sulphur (some include it)
-Nucleic Acids: Will contain phosphorus in relatively large amounts (contain phosphate groups)
[q] Polarity of water
[a] -It’s made up of two hydrogen atoms covalently bonded to an oxygen atom
-Oxygen atom has a high electronegativity and attracts the shared electrons more strongly
-This results in polarity (the O atom is slightly negative, and the H atoms are slightly positive)
-Because of this, water can form hydrogen bonds between the O of one molecule and the H of another
[q] two water molecules bonding
[a]
[q] Cohesion in relation to water
[a] -When two identical molecules ‘stick’ together (via intermolecular bonding)
-Water molecules are cohesive (they an ‘stick’ together via hydrogen bonding)
[q] Adhesion in water bonding
[a] When two different molecules ‘stick’ together (via intermolecular bonding)
-Water molecules are adhesive with polar or charged substances
[q] Significance of adhesion and cohesion for water
[a] -Adhesive properties result in capillary action when in contact with charged or polar surfaces
-Significant because it allows for transpiration stream in plants (flow of water against gravity)
-Cohesive results in water having higher surface tension because of extensive H bonding
-Significant as it allows for small insects to move along surface of water
[q] thermal properties of water
[a] -Water molecules can form extensive hydrogen bonding between molecules, which requires energy to break
-This means it takes a lot of thermal energy to change temp. (state) of water
-Hence, water has a high heat capacity (and high heat of vaporization/fusion)
[q] significance of the thermal properties of water
[a] -Because water has a high specific heat capacity, it functions as an excellent biological coolant
-Sweating results in evaporative cooling, as ambient heat is absorbed to evaporate water (breaks H bonds)
-This cools the air surrounding the skin and directly draws heat from the skin
[q] H20 and CH4 (methane)
[a] Similarities: Both have similar size and weight. They have comparable valence structures
Differences: water has a higher boiling and melting point. Water has a higher specific heat capacity. this is because water is polar and can form hydrogen bonds (methane is non-polar so it cannot form H bonds)
[q] Hydrophilic
[a] Substances that are soluble in water (lit. “water loving)
[q] Hydrophobic
[a] bigoted against water, so it is insoluble in water (lit. “water hating”)
[a] -Ionic compounds (ex: salt) dissociate in the water and are transported within blood plasma in a dissolved state
-Glucose and other monosaccharides are water soluble and hence are transported freely within blood plasma
-Amino acids are zwitterions and can freely be transported within blood plasma in an ionized state
-Oxygen is soluble in water, but only in low amounts (most O2 is complexed to hemoglobin in red blood cells)
-Lipids are non-polar and insoluble in water (transported in blood as lipoproteins)
[a] -Monosaccharides are joined together by condensation reactions to form polysaccharides (water produced)
-Covalent bond connecting the monosaccharides together is called a glyosidic linkage
-Polysaccharides can be digested into smaller oligosaccharides via hydrolysis reactions (water is required)
[a] Monosaccharides: Glucose, Glactose, Fructose (good flavor 🙂
Disaccharides: Lactose, sucrose, Maltose (length supports movement)
Polysaccharides: Cellulose, Glycogen, starch (hint: can be stored)
[a] -Short-term memory energy source (ex glycogen and starch)
-Structural component (ex cellulose in plant cell walls)
-Cell recognition and signalling (ex glycoproteins in plasma membranes
[a] Monomer: B-glucose
Bonding: 1-4 linkages
-Shape: Linear (sheets)
-Function: structural components of plant cell walls
[a] Monomer: a-glucose
Bonding: 1-4 linkages
Shape: linear (helical)
-short term energy storage in plants (type of starch)
[a] Monomer: a-glucose
Bonding: 1-4 linkages AND 1-6 linkages
Shape: less branched (~20 per units)
Function: Short-term energy storage in plants (type of starch)
[a] Monomer: a-glucose
Bonding: 1-4 linkages AND 1-6 linkages
Shape: more branched (~per 10 units)
Functions: Short-term energy storage in ANIMAL cells
[a] -Simple lipids: Triglycerides
-Compound lipids: phospholipids, sphingolipids, etc
-Derived lipids: steroids, cholesterol
[a] -Storage of energy (ex: triglycerides)
-Hormonal role (ex: steroids)
-Insulation (ex: sphingolipids)
-Protection of organs (ex: triglycerides, waxes)
-Structural components (ex: phospholipids)
Acronym: SHIPS
[a] Storage: triglycerides=long term, carbs=short term
Osmotic effects: Triglycerides have less effect on osmotic pressure (they are hydrophobic/not a solute)
Digestion: carbs are easier to digest (more readily consumed and can be digested anaerobically)
ATP yield: lipid digestion has higher ATP yield (~2x as much energy per gram)
Solubility: Triglycerides are insoluble in water and hence harder to transport
[a] -Protein digestion produces nitrogenous waste (bc of the presence of an amine group)
-Nitrogenous wastes are toxic to cells (must be removed via excretion to the kidneys)
[a] Saturated: lack a double bond (possess maximal amount of H atoms)
Unsaturated: fatty acids possess double bonds (may be monounsaturated or polyunsaturated)
[a] -H atom on the same side of the double bond
-Double bond creates kink in fatty acid chain
-Are loosely packed and usually liquid
-Occurs commonly in nature
-Generally considered good for health
[a] -H atoms on opposite sides of the double bond
-Double bond does NOT create kink in the chain
-Are tightly packed and usually solid
-Occurs in process oods
-Generally considered bad for health
[a] Low density (LDLs): transport cholesterol from the liver to the rest of the body
High density (HDLs): Scavenge excess cholesterol and return it to the liver for disposal
[a] -Cis fats raise levels of HDL (lowers blood cholesterol)
-Saturated fats raise levels of LDL (raise blood cholesterol)
-Trans fats raise levels of LDL and lower levels of HDL (significantly raise blood cholesterol)
-Cis fats are generally considered good for health, saturated and trans are considered bad
[a] -High levels lead to hardening and narrowing of arteries
-The cholesterol forms fat deposits in the arterial lining, leading to the development of plaques
-If a plaque ruptures, blood clotting will cause the vessel to become blocked
-If coronary arteries become blocked, coronary heart disease will result (resulting in heart attacks, etc)
[a] Evidence for: A positive correlation exists between intake of saturated fats and incidence of CHD. Intervention studies demonstrate that lowering intake of saturated fats reduce onset of CHD. In patients that have died from CHD, fatty deposits with high levels of trans fats were found in arteries.
Evidence against: Certain populations have high fat intakes but low rates of CHD (eg: maasai tribe in africa). Genetic factors play significant role. Cohort size and comparison and study duration influence results from intervention studies
[a] -Amine group on the left
-Variable (R) group on the bottom
-Carboxyl group on the right
-hydrogen on top
-Carbon in the middle
[a] -Amino acids are joined via condensation reactions to form dipeptides (a water molecule is produced)
-The covalent bond that connects amino acids together in a polypeptide chain is called a peptide bond
-Polypeptide synthesis occurs at the ribosome via the process of translation
[a] -Far left: amino group
-Carbon in the middle of the left amino acid
-R group on bottom
-Hydrogen on top of the carbon
-Peptide bond formed from the condensation of the OH of the left-ward amino acid and the right-ward amino acid’s Dihydrogen mononitroxide (forms a water molecule that leaves, forming the peptide bond)
-Carbon group connects to that
-Hydrogen group on top
-R group on bottom
-Carboxyl group on the far right
-This produces a water molecule
[a] -There are 20 different groups within nature
-They’re different according to the chemical composition of their variable side chain (the ‘R’ group)
NOTE: you will not have to memorize all 20, only that there are 20
[a] Primary: Order/sequence of amino acids within a polypeptide chain. Formed via peptide bonds between the amine and carboxyl group of adjacent amino acids. Primary structure determines all subsequent levels of protein structures.
Secondary: the folding of a polypeptide chain into repeating arrangements (alpha helices or beta-pleated sheets) (Looks kind of like RNA)
Tertiary: Overall three-dimensional shape of the polypeptide chain. Formed via a variety of bonds / interactions between the variable side chain (R groups). These interactions may include hydrogen bonds, ionic bonds, disulphide bridges or hydrophobic interactions.
Quaternary structure: The presence of multiple polypeptides or prosthetic groups to form a biologically active protein. Not all proteins have this form of structure.
[a] -Structure (ex: spider silk, collagen)
-Hormones (ex: insulin, glucagon)
-Immunity (ex: antibodies)
-Transport (ex: hemoglobin)
-Sensitivity (ex: rhodospin)
-Movement (ex: actin, myosin)
-Enzymes (ex: catalase, Rubisco)
Acronym: SHITSME
[a] -Temp. as thermal energy breaks hydrogen bonds responsible for tertiary structure which results in loss of function
-pH as amino acids are zwitterions–possessing both positive and negative regions (amine and carboxyl groups)–so altering the pH will change the charge and solubility of the proteins, changing the structure
[a] -Genes are sequences of DNA that encode polypeptides
-Typically, one gene equals one polypeptide–however, exceptions exist (ex: tRNA genes)
[a] 1. Enzyme and substrate collide in an appropriate orientation (substrate binds to the enzyme’s active site)
2. Enzyme and substrate form a complex, leading to catalysis (enzyme-substrate interaction shows specifically)
3. Substrate is converted into a product (enzyme may stress the bonds within the substrate to catalyze this process)
4. Enzyme and product dissociate (enzyme is not consumed by the reaction and may be re-used)
[a] Temp: increases kinetic energy of particles, leading to more frequent collisions
Substrate concentration: increases frequency of collisions with enzymes
Enzyme concentration: increases frequency of collision with substrate
[a] At low temps, there is insufficient activation energy for reaction to proceed.
-As temp. increases, the rate of reaction increases.
-At a certain temp. the enzyme peaks.
-After that, the enzyme denatures
[a] -Enzymes have an optimal pH at which the rate of reaction is highest.
– At higher and lower pH levels, activity will decrease (leading to a bell curve).
– This is because pH affects the charge and solubility of the enzyme.
-The change in the enzyme’s chemical properties causes it to denature.
[a] -Enzyme activity increases as substrate concentration increases, as there are more substrate particles, leading to a higher rate of successful collisions.
-At a certain point, the rate of enzyme activity will plateau, as all the active sites are occupied.
[a] -Immobilized enzymes have been fixed to a static surface to increase enzyme efficiency
-Enzyme concentrations are conserved, as the enzyme is not dissolved–so it cannot be re-used
-Product is easily separated from enzymes, as the enzymes are fixed in position
-Examples include food production, medicine, and bio-fuel products
[a] -Lactose is fixed to agarose beads (lactase purified from yeast or bacteria)
-Milk is passed over the immobilized enzyme, becoming lactose free
-This milk provides a source of milk and other dairy products for lactose-intolerant individuals
-increases sweetness in the absence of artificial sweeteners (monosaccharides are sweeter in taste)
-Reduces the crystallization of ice-creams (monosaccharides are more soluble, less likely to crystallise)
[a] -measure time taken for an enzyme-soaked disc to rise in solution.
-Measure gas formation via pressure change (w/ data logger) or displacement of a syringe cap
[a] -Measure color change with a colorimeter (starch is stained purple by iodine)
-measuring volume change via dialysis tubing (starch is impermeable to tubing, maltose is not)
[a] -Measuring volume of liquid produced as a consequence of the breakdown in cell wall
-measure the digestion of pectin via percentage weight change
[a] -The four DNA basis are: Guanine (G), Cytosine (C), Adenine (A) and Thymine (T)
-RNA has uracil (U) instead of thymine
-G and A are double-ringed purines, while C, T, and U are single0ringed pyrimidines
-G and C pair via three hydrogen bonds; A and T/U pair via two hydrogen bonds
[a] Sugar: Deoxyribose
Bases: G, C, A, T
Strands: double stranded
[a] Sugar: ribose
Bases: U, A, C, G
Strands: one (usually)
[a] -Messenger RNA (mRNA)–An RNA copy of a DNA
-Transfer RNA (tRNA)–Transfers amino acids to the ribosome
-Ribosomal RNA (rRNA)–The catalytic component of ribosomes
[a] -DNA nucleotides are linked by covalent phosphodiester bonds (between the 5′-phosphate and 3′-hydroxyl of two nucleotides) to form long polynucleotide strands
-Two strands join together via complementary base pairing (G pairs with C via 3 H bonds, a pairs with T via 2 H bonds)
-The two strands run antiparallel to each other so the bases face each other and form hydrogen bonds
-The double stranded DNA then twists into a double helix
-Each twist occurs every ~10 nucleotides.
[a] Linus Pauling: Identified molecular distances and bond angles for basic molecular structures
Phoebus Levene: Identified structure of nucleotide (sugar & phosphate base)
Erwin Chargaff: Determined that there is an equal number of purines and pyrimidines
Rosalind Franklin: Identified the organization of DNA into helical structures
[a] -Watson and Crick used the above knowledge and constructed DNA models through trial and error
-They demonstrated that DNA strands were antiparallel and formed a double helix
-They also showed complementary base pairings
[a] When a new double-strand molecule is formed:
-One strand is from the original template molecule (conserved)
-One strand is newly synthesized (not conserved)
[a] -Meselson and Stahl treated DNA with a heavier nitrogen isotope (15N) and then replicated the presence of a lighter nitrogen isotope (14N) so template DNA and newly synthesized DNA could be differentiated
-Results supported a semi-conservative model of DNA replication:
-After one division, all molecules contained both 15N and 14N
-After two divisions, some molecules contained both 15N and 14N, while other molecules only contained 14N
[a] -Helicase unwinds and separates double-stranded DNA molecules (by breaking the hydrogen bonds between the complementary base pairs
-breaks hydrogen bonds between complementary base pairs
[a] -This synthesizes a new strand (complementary to the template strand)
-Nucleotides align opposite their partner, and DNA Pol III covalently joins them together
-DNA Pol III synthesizes a new strand in a 5′ – 3′ direction
[a] -Free nucleotides can only align opposite their complementary base partner (A – T, C – G)
-This means a newly synthesized strand will be identical to the complementary partner of a template strand
-Hence, the base sequence is conserved
[a] -PCR is used to rapidly amplify minute quantities of DNA
-It involves a thermal cyler and three repeating steps
1: Denaturation: DNA is heated to separate strands
2: Annealing: primers are introduced to designate copying points
3: elongation: Taq polymeras–with heat resistance to avoid denaturing during PCR–synthesize the new strand
-These three steps double the amount of DNA, so a typical reaction of 30 cycles will produce of 1 billion copies of desired DNA sequences.
[a] -Antisense strands are the DNA strand that ARE transcribed (complementary to eventual RNA sequence)
-Sense strand is the strand that is NOT transcribed (identical to the RNA sequence – except the DNA strand has T and not U)
[a] -RNA polymerase unwinds and separates the double stranded DNA and then synthesizes a new RNA strand
-Based on the antisense template, the RNA strand is then released and the DNA double helix reforms
[a] -This is a set of rules by which information encoded by mRNA is translated into polypeptides
-Amount of specific amino acid encoded by each triplet of mRNA bases are identified (codon)
-There are 64 possible codon combinations, but only 20 possible amino acids
-This means some codons code for the same amino acid (degeneracy)
[a] Messenger RNA – contains the genetic instructions
Ribosome – site of translation
Codon – triplet bases denoting a specific amino acid
Anticodon – complementary sequence on tRNA molecule
Transfer RNA – transfers amino acids to ribosome
Amino acid – monomeric component of a polypeptide chain
Peptide band – the covalent bond formed between amino acids
Polypeptide – the end product of translation
Acronym: MR CAT APP
[a] -Ribosome binds to mRNA and moves along it in a 5′ – 3′ direction, reading the sequence in codons
-Each codon encodes a specific amino acid, which is brought to the ribosome by tRNA molecule
-Each tRNA is specific for a particular codon because of the presence of a complementary anticodon
-The tRNA molecules bring the amino acids to the ribosome in an order the codon sequence determined
-The ribosome moves along the mRNA, joining the amino acids together via peptide bonds
-Translation of a polypeptide begins at a START codon (AUG) and it finishes at a STOP codon
[a] -missense mutations are when a mutation in RNA happens, and it causes a change in the sequence
-A silent mutation is when a mutation in the RNA occurs, but no change happens
-Nonsense mutations create a STOP codon, which prematurely ends the polypeptide chain
[a] -The genetic code is universal, meaning (almost) all organisms follow the same set of genetic instructions
-This means that a DNA sequence from one organism can be successfully translated by another organism
-Example, the gene for insulin is extracted from human cells and inserted into bacterial cells
-The bacteria can now produce human insulin, as they reproduce very quickly
-This can be used for the production of insulin for people with type I diabetes
[a] -ATP is composed of a sugar and a base (adenosine) connected to three phosphate groups
-When a phosphate is cleaved (to form ADP + Pi) the energy stored in the bond is released
[a] -Oxygen not required
-Only 2 ATP yield
-products:
-Animals: Lactic acid
Plants: ethanol and CO2
Location: Cytosol
[a] -Oxygen required
-High yields (36-38 ATP)
-Products: CO2 and H2O
-Happens in the Cytosol and mitochondria
[a] Purpose: Restore stock of NAD+ needed for glycolysis; allows ATO to continue to be produced in the absence of O2 (otherwise respiration would stop)
-Fermentation in animals reversibly converts pyruvate to lactic acid (and frees up NAD+)
-In plants, it reversibly converts pyruvate to ethanol and CO2 (frees up NAD+)
[a] -It measures respiration rate–either by amount of CO2 produced or O2 consumed
-A manometer can accomplish this by recording the pressure change (as a moving bubble in solution) that occurs when O2 is consumed (must include a CO2 absorbent)
[a] Action: The range of wavelengths used by a plant for photosynthesis (red and blue is used for high photosynthetic rate, but green is not)
Absorption spectrum:The range of wavelengths absorbed by a plant (each pigment has its own spectrum). For chlorophyll, red and blue are absorbed, but green is reflected.
[a] -Chlorophyll absorbs light, which triggers the production of ATP
-Light is also responsible for the photolysis of water, which produces hydrogen (carried by NADPH)
-The photolysis of water also produces O2 gas as a by-product
[a] -The products of the light-dependent reaction (NADPH and ATP) are used in the light-independent reaction
-These reactions fix carbon (from CO2) to form organic molecules (such as carbohydrates)
[a] -Pigments are dissolved in a fluid (mobile phase)
-Fluid is then passed through a static material (stationary phase)
-Different pigments pass through the static material at different speeds, becoming separated
-A retardation factor (Rf) can be assigned to each pigment, which allows for identification
[a] -Temperature affects enzyme activity (enzymes control photosynthesis)
-Activity initially increases as a rise of kinetic energy results in more frequent collisions
-Above a certain temperature, activity decreases as enzymes denature
[a] -Increasing light levels result in more photoactivation of chlorophyll (= increased activity)
-At a certain intensity, all chlorophyll are photoactivated and so activity plateaus
[a] -CO2 is fixed (via enzyme) to form organic compounds
-Activity increases at higher concentrations as there are more frequent collisions
-Above a certain level activity will plateau as all enzyme active sites are occupies
[a] -Screening for known genetic conditions
-Discovering new drug treatments and medications (ex: phamacogenomics)
-Establishing ancestral lineage
[a] 1. Physical (ex: radiation)
2. Chemical (ex: tobacco and other carcinogens)
3. Biological (certain viruses)
[a] Stomatic: affects body cells and cannot be inherited by offspring
Germline: Affects sex cells and will be passed onto offspring
[a] -Mutation changes GAG to GUG on the mRNA transcription
-Mutation affects the 6th codon of the hemoglobin beta chain gene
-the mutation changes the amino acid from Glutamic acid to valine
-This causes the hemoglobin to form insoluble strands, which causes them to clump together
-The red blood cells adopt the characteristic of a sickle cell shape
-The sickle cells break down, leading to anemia and reduces O2 transport
-the sickle cell mutation demonstrates co-dominance
-The trait shows heterozygous advantage (resistance to malaria)
[a] -DNA is circular
-DNA is naked (not bounded to proteins)
-Single chromosome (called the genophore)
-found in the nucleoid region of the cytosol
[a] -DNA is linear
-DNA is bound to histone proteins
-Chromosome may exist in pairs (diploid)
-Found in the nucleus
[a] -Plasmids are circular DNA molecules capable of autonomous replication and transcription
-They can be transferred between bacteria via bacterial conjugation
-They are also used as a vector for gene transfer in scientific experiments
[a] -Cells were grown in a solution including radioactive thymidine (tritated thymidine)
-The radioactive thymidine was incorporated into the DNA of the cell (T present in DNA but NOT found in RNA)
-The chromosomes were then isolated and fixed to a photographic surface
-This surface was immersed in a solution of silver bromide (which turns into metal grain if exposed to radiation)
-The silver grains appear only where the DNA was present, allowing chromosome length to be determined
[a] -Chromosome pairs that share the same structural features and have the same genes at the loci position
-They represent the maternal and paternal copies of a chromosome
[a] -Chromosome number is a characteristic feature of a species
-Organisms with different haploid numbers will generally be unable to produce viable diploid zygotes (hybrid species are infertile)
[a] -Involves the separation of homologous chromosomes (bivalent / tretrads)
-Reduction division (diploid to haploid)
-Promotes genetic variation (crossing over and random assortment)
[a] -Involves separation of sister chromatids
-Is a mitotic division (haploid to haploid)
-Does not promote genetic variation
[a] -Homologous chromosomes are the maternal and paternal copies of a given chromosome
-Homologous chromosomes have the same structure and the same genes at the same loci position
Sister chromatids are the duplicated copies of a chromosome’s DNA (copied during S phase of interphase)
[a] Meiosis:
-Type of cells: sex cells( ͡° ͜ʖ ͡°)
Number produced: 4
number of divisions: 2
Ploidy of daughter cells: haploid
Genetics of daughter cells: shows genetic variations
Mitosis:
-Type of cell produced: body (somatic) cells
-Number produced: 2
-Number of divisions: 1
-Ploidy of daughter cells: diploid
-Genetics of daughter cells: Are genetically identical
[a] Crossing over involves the exchange of genetic material between non-sister chromatids of a bivalent
-Bivalents are connected at points called chiasma during the process of synapsis (during prophase I)
It is at these chiasma that recombination occurs
[a] -Bivalents will line up at the cell’s equator in a random orientation during Metaphase I
-Means there is an equal probability of a gamete containing the maternal OR paternal copy for any chromosome pair
-Because human cells have 23 chromosome pairs, there are 2^23 possible chromosomes (23 because there are 23 possible chromosome pairs that can have changes, the formula is 2^n, where n is the amount of chromosomes)
(this equates to over 8 million different gamete combinations)
[a] -When two haploid gametes fuse, they form a diploid zygote which can grow a new organism
-Because gamete fusion is random, each successive offspring will be composed of a distinct combination of maternal and paternal chromosomes
-This means every member of a species is unique (promoting biodiversity)
[a] -Non-disjunction describes the failure of chromosomes to separate during cell division
-If non-disjunction occurs in anaphase I, all four gametes will be affected (two=n+1; two = n-1)
-If it occurs in anaphase II, only two of the gametes are affected (two = n; one = n+1; one = n-1)
-If a gamete with one extra chromosome fuses with a normal gamete, the offspring will have trisomy
[a] -Trisomy 21 causes it
-increased maternal age increases risk of non-disjunction
[a] -Cells are isolated and treated with drugs to promote cell division (makes chromosomes visible to microscopes)
-Cells are arrested during mitosis and then chromosomes are isolated and visualized
[a] -Cells are extracted from the amniotic fluid
-Occurs later in the pregnancy (~15 weeks) but has a slightly lower risk of miscarriage (~.5%)
[a] -Cells are extracted from the placenta (chorionic villus)
-Occurs earlier in the pregnancy (~11 weeks) but has a slightly higher risk of miscarriage (1%)
[a] Method: Mendel crossed pure breeding pea plants (P generation), then crossed large numbers of the off spring (F1). He did this for a variety of different characteristics (ex: flower color, plant height, etc)
Conclusion: Mendel concluded that organisms have discrete factors that control inheritance of traits (genes). There are different versions of these factors (alleles) and each parents passes on one copy to offspring. Only one version gets expressed (dominance/recessiveness)
[a] -Parents each pass on one copy of every chromosome to offspring via haploid gametes
-The resulting zygote is diploid and therefore possesses two copies of every gene
-These alternative copies of genes are called alleles
[a] -O is the universal donor
-AB is the universal acceptor
[a] -any gene/trait that is located on the sex chromosome ( ͡° ͜ʖ ͡°)
-Example 1: Hemophilia
example two: red-green color blindness
[a] -Autosomal recessive disease
-Caused by a mutation to the CFTR gene on chromosome 7
-Causes the production of sticky mucus leading to obstructed airways and digestive issues
[a] -Autosomal dominant disease
-Caused by a mutation to the HTT gene on chromosome 4
-Abnormal production of the Huntingtin protein leads to neurodegeneration and dementia
[a] Chernobyl: released more fissionable material with longer half lives
Hiroshima: Bomb was detonated above ground and radiation was dispersed
Therefore, chernobyl responsible for more severe long-term health effects (ex: cancer)
[a] -PCR is used to rapidly amplify minute quantities of DNA
-It involves a thermal cycler and three repeating steps:
-Denaturation: DNA is heated to separate strands
-annealing: primers are introduced to designate copying points
-Elongation: TAQ polymerace (heat resistant so it does not denature from heat) synthesizes new strand
-These three steps double the amount of DNA, so a typical reaction of 30 cycles will produce over 1 billion copies of desired DNA sequence
[a] -Gel electrophoresis separates fragments of DNA or protein based on size
-DNA is run in an agarose gel (moves towards the positive terminus as phosphate is negative)
-Proteins are run on a polyacrylamide gel after first being treated with SDS (homogenises protein charge)
[a] -Plasmids
-Viruses
[a] -Gene of interest and plasmid vector are isolated from cells and amplified with PCR
-Gene and plasmid are cut with restriction enzyme
-DNA ligase fuses together gene and plasmid to form a recombinant construct
-The construct is then inserted into a host cell (via any of a number of different techniques)
-Transgenic cells are then selected by growing on antibiotic media (the plasmid has a resistance gene)
-The transgenic cells are then grown in culture and the newly expressed protein can then be extracted
-An example of this process is the mass reproduction of human insulin by transgenic bacteria
[a] -STRs are short repeating sequences in non-coding DNA
-Different individuals have different numbers of repeats, so by comparing STR loci, unique profiles emerge
[a] -Forensic investigations
-Paternity testing
[a] Benefits: improve yields. Potentially long shelf life. reduces need for chemical pesticides. Allows growth in wider areas (ex: salty soils)
Risks: Risks of cross contamination (ex: super weeds). Threatens native biodiversity. Difficult to police internationally. parenting could lead to monopolies
[a] -Budding (ex: yeast)
-Binary fission (hydra)
-Fragmentation (starfish)
-Parthenogenesis (some fish species)
[a] -Plants retains pluripotent cells (called meristem) and can reproduce asexually via vegetative propagation
-hence new plant clones can be grown from stem cutting
[a] -embryonic cells retain pluripotency, and by dividing the embryo into two cell masses, and each can grow into a new organism. Because these cells have identical genetic information, they will form clones
-Nucleus removed from diploid body cell of an adult, egg is enucleated via uv radiation, and diploid nucleus is inserted into enucleated egg. Egg stimulated to divide by electric shock, and as a result, all DNA comes from diploid nucleus, and resulting embryo will be a clone of the adult.
[a] -A substance (found in food) used by an organism to survive, grow and reproduce
-There are 6 major nutrients: carbs, lipids, proteins, vitamins, minerals, and water
[a] Synthesize their own organic molecules from simple inorganic substances (ex: CO2, nitrates)
-Energy derived from sunlight OR oxidation of molecules
[a] Energy flows through an ecosystem and is lost–requires resupply from a constant energy source (ex: sun)
-Nutrients are finite and are recycled within a closed ecosystem
[a] -Decomposers release enzymes to externally break down organic materials
-this allows for inorganic compounds to be replenished within the environment (ex: returned to the soil)
[a] -Quadrats
-Transects
[a] -The position of an organism occupies within a feeding source
-Producers always occupy the first level
[a] Food chain: linear feeding relationship between species in a community
Food web: multiple food chains all in one place
[a] -Heat
-Converted into another form of energy
-Stored chemical energy remains unconsumed
[a] -Light energy is the initial energy source for almost all communities
-It’s converted into chemical energy (organic molecules) by producers / autotrophs via photosynthesis
-the organic molecules are converted into usable energy (ATP) via cell respiration
-Heterotrophs (consumers) ingest these organic compounds to undergo cell respiration
-Energy transformations are only ~10% efficient–the majority is lost as heat
[a] -Pyramids of energy show the amount of energy at each trophic level of the food chain
-They will never appear inverted as some of the energy at each trophic level is always lost
-Each level should be roughly 1/10 of the size of the previous level
-Producers will always occupy the bottom
[a] -Some CO2 in water stays as dissolved gas, however most reacts to form hydrogen carbonate ions
-When the ions come into contact with rocks/sediments, they commonly form calcium carbonate (limestone)
-In animals, the calcium carbonate can be used to form hard exoskeletons (ex: coral and shells)
[a] -Methanogens produce methane from organic matter as a by-product of ANAEROBIC respiration
-the methane can either diffuse into the atmosphere or accumulate within the ground (natural gas deposits)
-Methane in the atmosphere is oxidized to CO2 and H2O after ~12 years
[a] -In anaerobic conditions (ex: waterlogged soils), saprotrophs can only partially decompose organic matter
-the remaining carbon-rich material stays within the soil and forms peat
-When compressed under sediment, the high pressure and heat force out moisture and turn peat into coal
[a] -Oil and natural gas form as the result of the decay of marine organisms on the ocean floor
-Sediments are deposited on top of the organic matter, creating anoxic conditions that prevent decomposition
-The compacted and heated organic matter forms oil and gas, which accumulates within porous rocks
[a] -When hydrocarbons are heated in the presence of oxygen, they undergo a combustion reaction to release CO2 and H2O as a by-products (this reaction is exergonic–produces energy)
-Sources of combustible hydrocarbons include biomass and fossilized organic matter (fossil fuels)
[a] Combustion of fossil fuels
deforestation
agricultural practices (produces methane gases)
[a] -Ability to absorb long-wave radiation
-Concentration within the atmosphere (determined by rate of release and persistence)
[a] -CO2 levels fluctuate annually (lower in summer because of higher photosynthesis rates)
-CO2 levels are steadily increasing (because of increased burning of fossil fuels)
-Global trends conform to northern hemisphere (because of more people and land mass)
-CO2 levels are now the highest ever recorded
[a] -Greenhouse effect functions to trap heat within the atmosphere and prevent rapid temp. changes
-incoming radiation (from the sun) is shorter wave radiation (ultraviolet radiation and visible spectrum)
-the Earth’s surface absorbs this radiation and reemits it at a longer wavelength (infrared radiation/heat)
-Greenhouse gases absorb and re-radiate the longer wave radiation and hence retain heat in the atmosphere
-The higher the concentration of greenhouse gases in the atmosphere, the more heat retained
[a] -Global temps
-Weather conditions (more frequent extreme conditions)
-Ocean currents (changes can cause longer el niño events)
[a] -strong positive correlation between CO2 levels and global temps
-there have been fluctuating cycles that can be attributed to global warm ages and ice ages
-CO2 levels are the highest ever recorded (however CO2 increases may not always precede temp increases)
[a] -Increased concentrations of dissolved CO2 lowers ocean pH (more carbonic acid = more acidity)
-More hydrogen ions also means there are less free carbonate ions for calcification (shell formation)
-Hence, an increase to water acidity correlates with significant thinning of calcium exoskeletons
-Low pH conditions are also detrimental to polyp survival, leading tp coral bleaching
[a] Argument 1: Solar activity has caused the current climate change
-There is no evidence of an increased number of sunspots
Argument 2: Current climate changes reflect a natural climatic cycle
-Changes do not usually occur as abruptly and past abrupt changes were always destructive to life
[a] -The cumulative change in the heritable characteristics of a population
-A change in the allele frequency of a gene pool across successive generations
[a] -Proposed that organisms evolved new characteristics as a consequence of habitual use or disuse
-Ex: a giraffe willed its neck longer and longer to reach the leaves
[a] -Proposed that organisms randomly develop new characteristics that were passed on for being beneficial
-Ex: long-necked giraffes survived over short neck giraffes because they could reach more leaves
[a] -Occurs when humans make a determination to select for some traits over others (via genetic modification or selective breeding)
-Think of crops and how they’re selected for
[a] -A fossil is the preserved remains or trace of an organism from the remote past (totality of fossils = fossil records)
-The fossil record shows that changes have occurred in organisms over time (evolution)
-The law of fossil succession show that certain organisms appear in the fossil record in a consistent order (indicates an evolutionary sequence of development from ancestral forms)
-Transitional fossils represent intermediary forms within the evolution of a genus (ex: archaeopteryx)
[a] -Fossilization preserves hard body parts (although soft parts may leave trace remains–such as imprints)
-Fossilization is a rare process that requires the preservation of remains (i.e. no scavenging), anoxic (lack of oxygen for decomposition) conditions, and high pressure (to turn hard body parts into fossilized minerals)
-These conditions are most likely to occur on land as a result of rapid burial
[a] -Selective breeding involves the international mating of animals with desired characteristics (artificial selection)
-As human intervention drives the selection process, changes will occur over fewer generations and will promote the evolution of phenotype extremities (hence, easier to identify the evolutionary pathway)
-Examples: horses bred for speed vs power, cows (Belgian blue = muscle mass), large variations of dogs
[a] -Homologous structures are anatomical features that share a common underlying structure despite having distinct functions–the pentadactyl limb of mammals is an example of a homologous structure
-The rapid diversification of the anatomical feature is the result of adaptive radiation
-Closely related species will have more similarities in their homologous structures
[a] -There is genetic variation within a given population (which can be inherited)
-There is competition for survival because of overproduction of offspring
-Environmental selection pressures lead to differential reproduction
-Organisms with beneficial adaptations are better suited for survival and more likely to reproduce and pass on genes
-Over generations, there is a change in the allele frequency within a population (evolution)
[a] Gene mutations
Meiosis (crossing over and independent assortment)
Sexual reproduction (random fusion of sperm and egg)
[a] biotic factors (predators/pathogens)
abiotic factors (weather events, nutrient supply, etc)
random phenonena (fires, floods, earthquakes, etc)
[a] -the rapid evolutionary diversification of a single ancestral line (ex: variety of beak size in Darwin’s finches)
-It occurs when members of a species occupy a variety of niches with different environmental selective pressures
[a] Polymorphic variants: melanic coloration (light versus dark pigmentation)
Selection pressure: predation by local birds
When high levels of soot blackened the local trees during the industrial revolution, the dark moth was better camouflaged and experienced less predation (so the dark pigmentation allele became more frequent as dark moths reproduced)
[a] polymorphic variants: drug-resistant versus drug-susceptible strains
Selection pressure: presence of antibiotics (ex: methicillin)
If exposed to an antibiotic, only the drug resistant strand survives. This increases the frequency of the drug resistant strand in the population
[a] -Darwin’s finches demonstrate adaptive radiation and show marked variation in beak size and shape according to diet
-Finches that feed on seeds possess compact, powerful beaks (large beaks are better equipped to crack seed cases)
-In 1977, an extended drought resulted in plants producing larger seeds with tougher seed casings
-Finches with larger beaks were better adapted and thus produced more offspring with larger beaks (evolution)
[a] -eukarya (all eukaryotic organisms)
-Archaea (prokaryotic extremophiles)
-Eubacteria (common pathogenic bacteria)
[a] Kingdom, phylum, class, order, family, genus, species
Acronym: Katy Perry Comes Over For Gay Sex
[a] -Groups organisms based on similarities first and then identify shared characteristics
-Shows how closely related organisms are and allows determination of evolutionary links
[a] -Selects unifying characteristics first and then groups organisms accordingly
-Easy to develop and relatively stable (unlikely to change) but don’t show evolutionary relationship
[a] -Differentiates organisms based on sequence similarities (genetics)
-Organisms with a greater similarity in DNA or amino acid sequences are more closely related
[a] -no ‘true’ leaves, roots, nor stems
-no vascularization (no xylem/phloem)
-spores in capsule at the end of stalk
think: moss
[a] -have vascularization
-spores in sporandia on underside of leaf
-have large fronds divided into leaves
Think: filin sounds kinda like fern
[a] -have vascularization
-have seeds (found in cones)
-leaves narrow with a thick, waxy cuticle
Think: literally has ‘cone’ in it
[a] -have vascularization
-have seeds in fruits
-have flowers as reproductive organs
Think: flowers in these, which hold pollen (plant sperm), which sperm is in the name
[a] -possess an asymmetrical body plan
-having no mouth or anus (have pores)
-May have structural support
ex: sea sponge
[a] -Possess radial symmetry
-Have mouth but no anus (single opening)
-Has tentacle and stinging cells (cnidocytes)
Ex: cool-looking jelly
[a] -possess bilateral symmetry
-Have mouth but no anus (single opening)
-Flattened body increass SA:Vol ratio
Ex: flatworm
[a] -possess bilateral symmetry
-have separate mouth and anus
-body composed of rings segments
Ex: worms
[a] -possess bilateral symmetry
-have a separate mouth and anus
-may have shell
ex: octopus
[a] -possess bilateral symmetry
-have a separate mouth and anus
-have jointed appendages and exoskeleton
ex: scorpions
[a] -covered in scales (bony plate of skin)
-Reproduce via external fertilization
-breathe through gills
-Are ectothermic
[a] -have moist skin, permeable to gases
-reproduce via external fertilization
-breathe via skin (may have simple lungs)
-are ectothermic
[a] -covered in scales (made of keratin)
-have internal fertilization (lay soft eggs)
-breathe via lungs (with extensive folding)
-are ectothermic
[a] -covered in feathers (made of keratin)
-have internal fertilization (lay hard eggs)
-Breathe via lungs (with parabronchial tubes)
-are endothermic
[a] -covered in skin (with keratin hair follicles)
-internal fertilization (and mammary glands)
-breathe via lungs (with alveoli)
-Are endothermic
[a] 1. Does it have hair / fur (NO: go to 2, YES: Mammal)
2. Does it have feathers? (NO: go to 3, YES: bird)
3. Does it have internal fertilization? (NO: go to 4, YES: reptile)
4: does it have gills as an adult (NO: amphibian, YES: fish)
[a] -The genetic code is (almost) universal and hence DNA and protein can be compared to determine relatedness
-mutations naturally accumulate and so sequence differences demonstrate the degree of divergence
-more similar the base sequence, the more likely the two species are to be related)
-Non-coding DNA mutates the fastest, followed by gene sequences, with amino acid sequences mutating slowest.
[a] -mtDNA is commonly used for comparing species that are closely related
-It is inherited maternally (more direct lineage)
-It lacks recombination (as mtDNA is circular)
-Has a relatively stable (and high) mutation rate
[a] -some genes or protein sequences may accumulate mutations at a constant rate (i.e. molecular clock)
-The time of divergence can be calculated based on the total number of mutations
-different genes may change at different rates and rate of change may differ between species
-over long periods, earlier changes may be reversed by later changed (confounding accuracy of predictions)
[a] 1. species of the figwort family have been reclassified based on chloroplast DNA
2. the homininae sub-family was created to group gorillas and humans together
[a] -look different
-because of selective pressures
-organisms share common ancestry
-arise via divergent evolution
example: pentadactyl limb in vertebrates
[a] -look similar
-because of common selective pressures
-organisms do not share a common ancestry
-arise via convergent evolution
-example: fins on dolphins and sharks
[a] -Salivary glands
-(O)esophagus
-Liver
-Stomach
-Gall bladder
-Pancreas
-Small intestine
-Large intestine
[a] -Temporary storage tank where food is mixed by churning and protein digestion begins
-It is lined by gastric pits that release digestive juices, which create an acidic environment
[a] -Produces a broad spectrum of enzymes that are released into small intestine via the duodenum
-Also secretes a certain hormones (insulin, glucagon), which regulate blood sugar concentrations
[a] -A long, highly folded tube where usable food substances (nutrients) are absorbed
-Consists of three sections: duodenum, jejunum, and ileum
[a] -Final section of alimentary canal, where water and dissolved minerals are absorbed
-Consists of the ascending/ transverse/ descending/ sigmoidal colon, as well as the rectum
[a] -Takes the raw materials the small intestine absorbed and uses them to make key chemicals
-Its role includes detoxification, storage, metabolism, bile production and hemoglobin breakdown
[a] Source: salivary gland
Substrate: starch
Product: Maltose
Optimal pH: ~7
[a] Source: gastric pit (stomach)
substrate: proteins
Product: Short polypeptides
optimal pH: ~2
[a] Source: pancreas
substrate: Triglycerides
product: glycerol + fatty acids
optimal pH: ~8
[a] -Continuous segments of longitudinal smooth muscle rhythmically contracting and relaxing
-Food is moved unidirectionally along the alimentary canal in a caudal direction (mouth to anus)
[a] -Contraction and relaxation of non-adjacent segments of circular smooth muscle in intestines
-contractions move chyme in both directions, allowing for a greater mixing of food with digestive juices
[a] -Its primary role is to absorb digested products
-Microvilli–Ruffling of epithelial membrane increases Sa
-Rich blood supply–Capillary network transports absorbed products
-Single layer epithelium–minimizes diffusion distance
-Lacteals–Absorbs lipids from the intestine into the lymphatic system
-Intestinal glands–exocrine pits release digestive juices
-membrane proteins–facilitates transport of digested materials
[a] -Starch is composed of glucose monomers in either linear (amylose) or branched (amylopectin) arrangement
-Amylase is an enzyme that digests starch (amylose into maltose; amylopectin into short dextrin chains)
-The pancreas plays a fundamental role in the digestion of starch molecules
-It secretes amylase and hormones (insulin and glucagon)that regulate glucose uptake by the liver
[a] 1. Plasma
2. Red blood cells (erythrocytes)
3. White blood cells (leukocytes)
4. Platelets (thrombocytes)
[a] -nutrients
-antibodies
-CO2
-hormones
-O2
-Urea
-Heat
[a] -Harvey disproved the prior theories of Galen by suggesting
-The major blood vessels (arteries and veins) are part of a single connected blood network
-Blood flow is unidirectional (because of valves) and continuous flows (it is not consumed by the body)
-The heart is a central pump (blood carried from the heart by the arteries and to the heart and veins)
[a] -deoxygenated blood returns from the body (via vena cava) to the RIGHT side of the heart
-It is pumped (by right atrium/right ventricle) to the lungs via the pulmonary artery
[a] -Oxygenated blood returns from the lungs (via pulmonary vein) to the LEFT side of the heart
-It is pumped (by left atrium/left ventricle) to the body via the aorta
[a] Blood speed: fast
Blood pressure: high
Size of lumen: narrow
Valves: no
Wall composition: Thick walls with large amounts of muscle and elastic fibers
Function: carry blood from heart
[a] Blood speed: low
Blood pressure: low
Size: extremely narrow
Valves: no
Wall composition: extremely thin wall composed of single layer epithelium
Function: gas/material exchange
[a] Blood speed: slow
Blood pressure: low
Size of lumen: wide
valves: yes
Wall composition: thin walls with small amounts of muscles and elastic fibers
Function: carry blood to heart
[a] -have thick walls and narrow lumens because they transport blood at high pressure
-Have muscular/elastic walls to stretch with pulse flow
[a] -Have thin walls with wide lumens and valves because they transport blood at low pressure
-Have valves to prevent backflow
[a] -Valves in veins and the heart ensure the circulation of blood is unidirectional by preventing back flow
-Heart valves include AV valves (tricuspid and bicuspid) and semilunar valves (pulmonary and aortic)
[a] -Heart beat is myogenic–means cardiac contraction is initiated by the heart
-Electrical signals are initiated by the sinoatrial (SA) node (the peacemaker)
-It stimulates the atria to contract and also relays signals to an atrioventricular node
-The atrioventricular node sends signals via the Bundle of His to Purkinje fibers
-These fibers innervate the ventricles and cause them to contract
[a] -The SA node (pacemaker) maintains the heart’s normal sinus rhythm (60-100 bpm)
-The peacemaker may be regulated by the medulla (brainstem), with sympathetic nerves increasing heart rate
-By releasing noradrenaline and parasympathetic nerves decreasing the heart rate by releasing acetylcholine
-Heart rate may also be increased by the release of epinephrine (aka adrenaline) into the bloodstream
[a] -Systole described the period of heart contraction
-Diastole describes the period of heart relaxation
[a] -Blood returning to the heart will flow into the atria and ventricles as the pressure in them is lowered
-As ventricles fill, atria contract (atrial systole), increasing pressure in atria and forcing blood into ventricles
-As ventricles contract, ventricular pressure exceeds atrial pressure and AV vales close to prevent back flow
-When ventricular pressure exceeds pressure in aorta, the aortic valve opens to release blood into the aorta
-As blood exists the ventricle, ventricular pressure falls below aortic pressure, so the aortic valve closes
-When ventricular pressure drops below atrial pressure, the AV valve opens and cycle begins again
[a] Causes: Atherosclerosis can be caused by age, hypertension, obesity, diseases (ex: diabetes), smoking, genetics, diet, and lack of exercise
Consequences: coronary heart disease occurs when coronary arteries become narrower. Coronary arteries oxygenate heart tissue so their occlusion results in myocardial infarctions (heart attack)
[a] -Antibiotics are compounds that inhibit or kill bacteria by targeting the structures or metabolic pathways of prokaryotes (not eukaryotes)
-Viruses don’t have metabolism and are therefore not affected1
[a] -Neutrophils: rapid response to microbial infections
-lymphocytes: specific (adaptive) immune response
-monocytes / macrophages: longer lasting response to microbial infections
-eosinophils: target multicellular parasites (too big for phagocytes)
-basophils: involved in inflammation (similar to most cells)
Acronym: Never Let Monkeys Eat Bananas
[a] -Lymphatic system is a transport system that protects the body by producing and filtering lymph
-Lymph contains white blood cells and arises from the drainage of fluid from blood and tissues
-Lymph is filtered at lymph nodes, where pathogens are removed before fluid is returned to venous circulation
-Major lymphatic organs include the spleen, tonsils, thymus and adenoids
[a] -Sin protects external structures and is a thick and dry region composed predominantly of dead cells
-Mucous membranes protect internal cavities and is a thin region composed of living cells that secrete mucus
-Sebaceous glands secrete biochemical agents / acids to inhibit bacterial growth
-Commensals (gut bacteria) prevent the colonization of harmful pathogens in the digestive tract
[a] -Injured cells and platelets release clotting factors
-Factors convert prothrombin (inactive) into thrombin (active)
-Thrombin converts fibrinogen (soluble) into fibrin *insoluble)
-fibrin forms a mesh of insoluble fibers that trap blood cells
-Clotting factors also cause platelets to become sticky and form a solid plug (clot)
[a] -Blood clots form in the coronary arteries when the vessels are damaged by cholesterol build-up (antherosclerosis)
-The restricted blood flow increases pressure in the artery, leading to damage to the arterial wall (plaques)
-If the plaque ruptures, blood clotting is triggered, forming a thrombus that restricts blood flow
-clot formation in coronary arteries leads to coronary thrombosis and heart attacks
[a] -Phagocytosis: pathogens are engulfed and destroyed by phagocytic leukocytes
-Inflammation: blood flow is increase to site of infection to increase leukocyte access
-Complement proteins: active a cascade that promotes pathogen detection and destruction
-Fever: increase body temp. to assist in pathogenic destruction
-Natural killer cells: non-specifically target viral-infected cells
[a] -Phagocyte (macrophages) circulate in blood but move to tissue upon infection
-Pathogens are engulfed by the phagocyte and internalized in a vesicle
-The vesicle may then fuse with a lysosome to digest the pathogen
-Antigenic fragments from the pathogen are presented on the macrophage
-These fragments are then presented to lymphocytes to help stimulate the production of specific antibodies
[a] Adaptive: it can differentiate between pathogens and target a response that is specific to a given pathogen
Memory: it can respond rapidly upon re-exposure to a specific pathogen, preventing disease symptoms
[a] -The antigenic fragments of pathogens are presented on the macrophages
-lymphocytes are a class of white blood cells that develop in the bone marrow
-macrophages present antigen fragments to helper T lymphocytes (TH cells)
-TH cells release cytokines to activate an antigen-specific B lymphocyte (B cell)
-The B cell divides and differentiates into plasma cells that produce antibodies
-A small portion of clones develop into memory cells (for long-term immunity)
[a] -hypersensitivity disorders (allergies)
-autoimmune disorders (multiple sclerosis, lupus)
-Immunodeficiency disorders (HIV/AIDS)
[a] -The Human immunodeficiency virus (HIV) is a retrovirus that infects helper T cells
-HIV is integrated into the genome of T cells and after years of inactivity the virus spreads
-Infected TH cells are lysed (destroyed) to release the virus from the cells
-This results in reduced immunity (AIDS) as antibody production is compromised
[a] -when a B cell encounters the allergen, it differentiates into plasma cells and makes specific antibodies (IgE)
-The IgE antibodies attach to mast cells, effectively ‘priming’ them towards the allergen
-upon re-exposure, the IgE-primed mast cells release large amounts of histomine which causes inflammation
[a] -Because gas exchange is a passive process, a ventilations system is needed to maintain a concentration gradient
-the lungs continually cycle fresh air into the alveoli from the atmosphere
-the lungs also have a very large surface area, so as to increase the overall rate of gas exchange
[a] -mediate gas exchange with capillaries
-are long and thin (lower diffusion distance)
-compromise most of the alveolar surface
[a] -Secrete pulmonary surfactant
-Reduces surface tension within alveoli (easier to inflate alveoli, preventing collapse)
[a] -Type II Pneumocytes secrete pulmonary surfactant which reduces the surface tension in alveoli
-As alveoli expand with gas intake, the surfactant becomes more spread out across the moist alveolar lining
-this increases surface tension and slows the rate of expansion, ensuring all alveoli inflate at the same time
[a] -Boyle’s Law: pressure is inversely proportional to volume (ie more volume = less pressure)
-Breathing utilizes antagonistic sets of reparatory muscles to facilitate the passage of air
-The muscles change lung volume to create a negative pressure vacuum
-when pressure in the lung is less than atmospheric pressure, air flows in to equalize (and vice versa)
[a] -Cellular respiration produces CO2 as a waste product
-rising levels of CO2 in the bloodstream alters the blood pH (lower)
-This triggers an increase in ventilation rates
[a] measures the speed (flow) or amount (volume) of inhalation or exhalation
-This data can be recorded with a spirometer
[a] -Cancer is the uncontrolled proliferation of cells, leading to abnormal growth (tumors)
-factors that can contribute to the development of lung cancer include genetics, age, some diseases, smoking asbestos, and radiation
[a] -lungs are vital to normal body function and thus the abrogation of their function is detrimental to health
-abnormal growth can impact normal tissue function, with symptoms varying according to size and location
-Lungs possess a rich blood supply, increasing the likelihood of the cancer spreading (metatosis)
[a] emphysema is the abnormal enlargement of alveoli (forms huge air spaces–‘bullae’)
-Emphysema is often caused by smoking, as chemicals in cigs damage alveoli
-The recruited phagocytes release elastase and the elastase destroys fibers in alveolar walls
[a] -the charge difference across a membrane when the neuron is not firing (~70 mV)
-Maintained by the sodium-potassium pump
[a] -the charge difference across a membrane when the neuron is firing (~30 mV)
-involves depolarization and repolarization
[a] -A sudden change in membrane potential–usually from a (relatively) negative to positive internal charge
-involves Na+ opening
[a] -The restoration of a membrane potential following depolarization (i.e. restoring a negative internal charge)
-involves K+ channels opening
[a] 1. Sodium-potassium pump maintains a resting potential
-It expels 3 sodium per 2 potassium admitted (active transport)
-This results in a negative membrane potential (roughly ~70mV)
2. Sodium channels open in response to signal at receptor / dendrite.
-There is a passive influx of sodium ions to cause depolarization
3. Potassium channels open in response to depolarization
-There is a passive efflux of potassium ions (repolarization)
4. The neuron needs a length of time needed before it can re-fire again
-During this refractory period, the resting potential is re-established by the NA+/K+ pump
[a] -This myelin sheath functions to improve transmission speed (via saltatory conduction)
-The action potential ‘hops’ between the gaps in the myelin sheath (called nodes of Ranvier)
-This increases transmission speed by ~100x
[a] -Excitatory neurotransmitters will depolarize a post-synaptic neuron (more likely to fire), whereas inhibitory neurotransmitters will hyperpolarize a post-synaptic neuron (less likely to fire)
-The sum of excitatory and inhibitory signals determines where the threshold for an action potential is reached
-Hence, the composition of neurotransmitters released determines the differential pathways of nerve signals
[a] -acetylcholine is a neurotransmitter that serves excitatory and inhibitory function–it is used to stimulate
-muscular contractions and it also promotes parasympathetic responses
-Acetylcholine is broken down in synapses by acetylcholinesterase (AChE) to prevent overstimulation of receptors
[a] Neonicotinoid pesticides bind irreversibly to acetylcholine receptors in insects
-AChE cannot break down neonicotinoids–this causes fatal overstimulation of receptors
[a] -Feedback mechanisms involve a change being detected by a receptor and a response initiated by an effector
-In negative feedback, the effect is antagonistic (opposite) to the stimulus
-This means the detected change is reversed
[a] 1. Body temp. (thermoregulation)
2. Blood glucose concentration
3. CO2 levels and blood pH
4. Water balance (osmoregulation)
[a] -Thermoreceptors (in skin) send signals to the hypothalamus and thyroxin is released from the thyroid gland
-Thyroxin increases the basal metabolic rate (which generates heat)
-When body temp. is low, thyroxin is released, and when temp. is high, thyroxin is not released
[a] -Photoreceptors detect light and send signals to the hypothalamus
-Light exposure inhibits the melatonin secretion from the pineal gland (hence, increased melatonin rates at night)
-High levels of melatonin promote sleep in diurnal animals (ex: humans)
[a] -appetite suppression is regulated by the hormone leptin (secreted by adipose tissue)
-leptin binds to receptors in the hypothalamus to inhibit/suppress appetite (lower food intake = lower weight gain)
-Over-eating causes more adipose cells to be produced, so more leptin is released, leading to desensitization
[a] -Blood glucose levels are regulated by pancreatic hormones insulin (from Beta cells) and glucagon) (from a cell)
-Insulin lowers blood sugar levels by stimulating glycogen synthesis and increasing rate of glucose breakdown
-glucagon raises blood sugar levels by stimulating glycogen breakdown and decreasing glucose breakdown
[a] Onset: childhood (early onset)
effects: body doesn’t produce insulin
Cause: Beta cells destroyed (maybe autoimmune)
Treatment: insulin injection
[a] onset: late onset (adulthood)
effects: body does not respond to inulin
Cause: insulin receptors down-regulated
Treatment: dietary management
[a] -The sex chromosomes will determine sex: Females have XX, males have XY
-Y chromosome contains SRY gene that causes gonads to develop into testes (in its absence, ovaries develop)
[a] -FSH acts on ovaries to stimulate follicular growth and stimulates estrogen secretion (from follicles)
-LH acts on ovaries to trigger ovulation, which results in a corpus luteum that produces progesterone
[a] -Estrogen and progesterone promote development and thickening of the endometrium
-They stimulate FSH/LH secretion in the follicular phase and inhibit FSH/LH secretion in the luteal phase
[a] 1. follicular phase:
-FSH stimulates growth of several follicles, the dominant follicle secretes estrogen which stops the growth of other follicles (lower FSH) and also stimulates endometrial development
2. Ovulation
-A surge in LH causes ovulation (egg release) and the rupturing of the follicle creates a corpus luteum
3. Luteal phase
-Corpus luteum makes estrogen / progesterone, which stimulates endometrial growth and inhibits FSH / LH
-Corpus luteum degrades over time, so estrogen / progesterone levels drop and endometrium is sloughed away
[a] -In the follicular and luteal phase, estrogen / progesterone inhibits FSH / LH production
-This is an example of this type of feedback as the response (estrogen production) is antagonistic to the stimulus (FSH/LH production
[a] -during ovulation, estrogen stimulates LH / FSH production (leading to a surge)
-this is an example of this type of feedback as the response (estrogen production) promotes the stimulus (FSH / LH production)–this feedback will cease when the follicle ruptures (ovulation)
[a] Stop menstrual cycle with drugs
Hormone treatments (FSH triggers superovulation)
Extract multiple eggs
Sperm selection
Fertilization (in vitro)
Implantation of embryos
Test for pregnancy
Acronym: SHE’S FIT
[a] -Chance for infertile couples to have children
-screening of embryos could decrease suffering from genetic disease
-Spare embryos can be stored for future pregnancies or used for research
[a] -IVF is expensive (access issues) and success rate is low (stressful)
-Could lead to eugenics
-Often leads to multiple pregnancies (extra risks)
-Issues concerning disposal of unused embryos (right to life concern)
-Inherited forms of infertility may be passed on to children
[a] -DNA was crystallized and then targeted with an X-ray (whose beam became diffracted by DNA crystals)
-The scattering pattern created by the diffracted x-ray was recorded on film
-This pattern was then analyzed to elucidate the structure of DNA
[a] -DNA is wrapped around histone proteins to form nucleosomes
-Nucleosomes are grouped together (chromatosomes) and then arranged into fibers (chromatin)
-DNA is usually organized as chromatin within the nucleus, except during cell division (when chromatin condenses to form chromosomes)
[a] euchromatin: more loosely packed and corresponds to active segments of DNA (active genes)
Heterochromatin: more densely packaged and corresponds to inactive segments of DNA
-Different cells have different segments of DNA packaged a euchromatin and heterochromatin
[a] nucleosome consists of DNA and histosone proteins
-DNA is wrapped around an octamer of histone proteins
-Nucleosomes are linked by an interconnecting H1 histone
-Nucleosomes serve two key functions
-Help supercoil DNA (improved packaging)
-Help to regulate transcription
[a] Satellite DNA (ex: short tandem repeats)
Telomeres (the terminal sections of chromosomes)
Introns (non-coding sequences within DNA
Non-coding genes (ex genes for tRNA or rRNA)
Gene regulatory sequences (ex promoters, enhancers, silencers)
Acronym: STING
[a] -Short tandem repeats (STRs) are short repeating segments within satellite DNA
-the number of repeats for a particular loci will differ between individuals
-the STRs can be excised and separated on a gel to create a distinct DNA profile of a given individual (the more STR loci included in the profile, the more unique the DNA profile will be for the individual)
[a] -Hershey and Chase demonstrated that DNA was the genetic material by using radioactively-labeled viruses
-Viruses were prepared with radioactive phosphorus (labeled DNA) or radioactive sulphur (labels protein)
-Viruses then infected bacteria, before the bacteria and virus were separated via centrifugation (bacteria is heavier and forms a pellet, while the smaller virus remains in the supernatant)
-When radioactive sulphur was used, radioactivity was detected in supernatant (not transferred to bacteria)
-When radioactive phosphorus was used, radioactivity was detected in pellets (WAS transferred to bacteria)
[a] Helicase: unwinds and separates double stranded DNA (breaks H bonds between the base pairs)
DNA Gyrase: Relieves torsional strain created by helicase action (i.e. prevents supercoiling)
SSB Protein: Prevents DNA strands from re-annealing (SSB proteins will be displaced by DNA pol III)
DNA primase: Lays down a short RNA primer to provide an initiation point for polymerization (DNA Pol III can only add nucleotides to the 3′-end of an existing nucleotide chain)
DNA Pol III: Extends the nucleotide chain from the primer (dNTP’s align opposite complementary bases and DNA pol III covalently joins them together)
DNA Pol I: Removes and replaces RNA primers with DNA nucleotides
DNA Ligase: covalently joins Okazaki fragments together (on lagging strand)
[a] -DNA strands are antiparallel, so DNA pol III moves in opposite direction on the two strands of DNA
-On the leading strand, DNA pol III moves in the same direction as the helicase, so synthesis can continue
-On the lagging strand, DNA pol III moves in the opposite direction to helicase, so synthesis is discontinuous
-The fragments generated on the lagging strand are called Okazaki fragments
[a] -Deoxynucleoside triphosphates align opposite their complementary base partner
-DNA pol III cleaves two of the phosphates and uses energy to form a covalent phosphodiester bond
-In this way, DNA pol III synthesizes a new DNA strand
[a] -Dideoxynucleotides (ddNTP’s) lack the 3′-hydroxyl group needed to form a phosphodiester bond
-this means the inclusion of the ddNTP will terminate the extension of a DNA sequence at that point
-Four PCR cycles are set up, each with a differetn ddNTP (ddA, ddT, ddG, or ddC) and a stock of normal bases
-Each time the ddNTP is incorporated the sequence stops, generating fragments
-When these fragments are separated and then ordered according to their length, the DNA sequence is discerned
-This process can be automated by using flourescently labelled ddNTPs that can be detected by machines
[a] promoter – initiation point (where RNA polymerase binds)
Coding region – Sequence that is transcribed
-Terminator – termination point
[a] -RNA polymerase attaches to the promoter (requires the presence of transcription factors)
-RNA polymerase unwinds the DNA and separates the strands
-Nucleoside triphosphates (NTPs) align opposite complementary bases and are joined by RNA polymerase
This continues until the terminator at which point the enzymes and transcript dissociate from the DNA
[a] 1. Methyl cap added to the 5′-end (protects against degradation and allows recognition by ribosome)
2. polyadenylation occurs at the 3′-end (improves stability and facilitates nuclear exports)
3. Splicing occurs (introns are removed)
[a] -Transcriptional activity is regulated by transcription factors which mediate binding of RNA polymerase to the promoter (the initiation point for transcription of a gene sequence)
-the presence of certain transcription factors may be tissue-specific (explaining why different genes are activated in different tissues) and environmentally sensitive (explaining why expression patterns can change)
[a] -Environmental factors can trigger the production (or change in levels) or transcription factors
-Example: hydrangea flowers change color according to the pH of the soil
[a] -the binding of RNA polymerase to the promoter can be controlled by regulatory proteins
-activators bind to enhancer sequences and make it easier for the enzyme to bind (increasing expression)
-Receptors bind to silencer sequences and make it harder for the enzyme to bind (decreases expression)
[a] -Nucleosomes are involved in the supercoiling of DNA (supercoiled DNA is inaccessible for transcription)
-Acetylation of the histones make the DNA less tightly coiled (increases gene expression)
-Methylation of the histones makes the DNA more tightly coiled (decreases gene expression)
[a] -Direct methylation of DNA also decreases gene expression (preventing binding of transcription factors)
-Hence, genes that are methylated are not expressed, while genes that are not methylated are expressed
-Because DNA methylation is influenced by environmental factors, identical twins develop different methylation patterns over time–this explains why twins may look different despite having identical genomes
[a] Acceptor stem – Carries the amino acid
T arm – associated with the ribosome (via E, P, A sites)
Anticodon – associates with mRNA (via complementary codon)
D arm – associates with tRNA–activating enzyme
[a] -Each tRNA molecule carries a specific amino acid (designated by the codon / anticodon)
-Hence, different tRNA molecules associate with specific tRNA-activating enzymes
-Enzyme binds ATP to an amino acid (forming a ‘charged’ amino acid-AMP complex)
-the charged complex is then transferred to the tRNA acceptor stem (and AMP is released)
-The purpose of ‘charging’ the molecule is to provide the energy needed in translation for peptide bond
[a] -ribosomes are composed of a large and a small subunit (made of protein and rRNA)
-The small subunit binds to mRNA
-the large subunit contains three tRNA binding sites (E, P, and A)
[a] Smaller than eukaryotic ribosomes
Prokaryote = 70S ribosomes
Eukaryotes – 80S ribosomes
[a] -Proteins synthesized by bound ribosomes have different destinations to those synthesized by free ribosomes
-ER-bound ribosomes = secretory proteins (or lysosome)
-Free ribosomes = intracellular proteins
[a] initiation: small ribosomal subunit binds to mRNA and moves along it in a 5′ -> 3′ direction until the START codon (AUG). Specific tRNA (carrying Met) binds to the START codon (via complementary anticodon). Large ribosomal subunit binds to the tRNA molecule (via the P-site), completing the ribosome
Elongation: another tRNA molecule binds to the next codon in the mRNA sequence (via the ribosomal A-site). The ribosome transfers the amino acid in the P-site to the amino acid in the A-site (via a peptide bond)
Translocation: Ribosome moves one codon position along the mRNA sequence (in a 5′ -> 3′ direction). Deacylated tRNA molecule moves to E-site and is released, while tRNA in the A-site moves to the P-site. A new tRNA enters the empty A-site and the elongation and translocation stages are continually repeated.
Termination: The ribosome reaches a STOP codon and a releasing factor is recruited. This causes the completed polypeptide chain to dissociate the ribosome to disassemble.
[a] -The order / sequence of amino acids within a polypeptide chain
-formed via peptide bonds between the amine and carboxyl groups of adjacent amino acids
-Primary structure determines all subsequent levels of protein structure
[a] -Folding of a polypeptide chain into repeating arrangements (alpha helices or beta-pleated sheets)
-Formed via hydrogen bonds between the amine and carboxyl groups of non-adjacent amino acids
[a] -The overall three-dimensional shape of the polypeptide chain
-Formed via a variety of bonds / interactions between the variable side chains (R groups)
-These interactions may include hydrogen bonds, ionic bonds, disulphide bridges or hydrophobic interactions
[a] -The presence of multiple polypeptides or prosthetic groups to form a biologically active protein
-Not all proteins have this structure
[a] -Competitive inhibitors are similar in structure and chemical properties to the substrate
-It can bind to the active site and block the substrate binding
increasing substrate concentration will reduce the effect of a competitive inhibitor
[a] -Relenza is a drug designed to treat infection with the influenza virus
-Influenza virions tether to infected cells via hemagglutinin and are released by the enzyme neuraminidase
-Relenza competitively inhibits the neuraminidase active site, preventing cleavage from hemagglutinin
-Thus virus cannot be released and the spread of infection is diminished
[a] -Non-competitive inhibitors bind to a site other than the active site (called an allosteric site)
-These inhibitors cause a conformational change in the enzyme, which alters the shape of the active site
-Thus the substrate can no longer bind (increasing substrate concentration will have no effect on inhibition)
[a] -Cyanide binds to a carrier protein in the electron transport chain and causes a conformational change
-The carrier can no longer shuttle electrons, so oxidative phosphorylation (aerobic respiration) is shut down
-Without energy (ATP) the cells die, making cyanide a very potent poison
[a] -reactions are slowed
-Maximal rate sill achievable (but needs higher substrate concentration)
[a] -Rate of reaction is slowed
-Maximal rate of reaction is less
-Increasing substrate concentration will NOT increase maximum reaction rate
[a] -End-product inhibition (or feedback inhibition) is when a product of metabolic pathway inhibits one of the enzymes involved in its production
-This allows reaction rates to be tightly regulated
[a] -In plants and bacteria, isoleucine can be synthesized from threonine
-this multi-step reaction involves the enzyme threonine deaminase
-Isoleucine can bind to an allosteric site on threonine deaminase and non-competitively inhibit it
-Thus when isoleucine levels are high its production is reduced, but when levels are low, production proceeds
[a] -Malaria is caused by the protozoan Plasmodia (whose metabolism is controlled by specific enzymes)
-Bioinformatic databases can be searched to identify molecules that structurally resemble specific substrates
-Combinatorial chemistry can then be used to modify these molecules to form effective inhibitors
-This modelling of desired chemicals is called rational drug design
[a] 1. ATP: an immediate energy source used by cells to fuel biological processes
2. hydrogen / electron carriers (e.g. NADH): an intermediate / transitional energy form
3. Organic molecules: stored energy (e.g. carbohydrates and triglycerides)
[a] Oxidation: loss
Reduction: Gain
[a] oxidation: loss
Reduction: gain
[a] oxidation: gain
Reduction: loss
[a] -Electron tomography involves repeated imaging of a mitochondria with a transmission electron microscope
-These cross-sections are taken at different angles along distinct planes
-The images are then compiled by computer to generate 3D representations of the organelle
[a] Inner membrane: highly folded (increases SA:Vol ratio so more oxidative phosphorylation occurs)
Matrix: Has appropriate enzymes and suitable pH for the Kreb cycle to occur
Outer membrane: Has appropriate carrier proteins for shuttling pyruvate into mitochondria
Intermembrane space: small volumes (maximizes proton gradient with the accumulation of hydrogen ions)
[a] 1. glycolysis (cytosol)
2. link reaction (from cytosol to matrix)
3. Kreb cycle (matrix)
4. electron transport chain (inner mitochondrial membrane)
[a] -Glucose is phosphorylated with 2 ATP (destabilizing the molecule)
-Molecule is then split in two (lysis) to form two 3C compounds
-These compounds are oxidized (NADH is formed)
-Four ATP molecules are produced (for a net gain of TWO ATP)
-the final product is two molecules of pyruvate (3C)
[a] -pyruvate is transported from the cytosol into the mitochondrial matrix
-Pyruvate is decarboxylated and oxidized (CO3 and NADH is produced)
-It is then converted to an acetyl compound and attached to coenzyme A to form acetyl CoA (2C)
[a] -Acetyl CoA combines with a 4C compound (oxaloacetate)
-The resulting 6C compound (citrate) is then broken back down into the original 4C compound (oxaloacetate)
-This series of reactions involves decarboxylation (CO2 is released) and oxidation (large amounts of hydrogen carriers are produced)
-These reactions also produce one molecule of ATP per cycle
[a] -Hydrogen carriers (e.g. NADH) donate high energy electrons to the electron transport chain
-As electrons move through the chain they lose energy, which is used to translocate protons to the intermembrane space–this creates an electrochemical gradient (or proton motive force)
-The proton gradient will cause the hydrogen ions to diffuse back into the matrix (chemiosmosis)
[a] -protons build up in the intermembrane space, creating a gradient
-the protons can only return to the matrix via a transmembrane enzyme called ATP synthase
-The movement of protons through this enzyme triggers the formation of ATP (from ADP and Pi)
-Because the proton gradient was created by the oxidation of NADH, this form of ATP production is called oxidative phosphorylation
[a] -De-energized electrons must be removed from the electron transport chain for it to continue to function (otherwise the chain would become blocked)
-O2 is the final electron acceptor–it takes the electrons (along with the protons from the matrix) to form water (the removal of protons also helps to maintain the gradient needed for chemiosmosis)
[a] Glycolysis:
-oxidation = 2 NADH
-ATP formation = NET 2 ATP (substrate level, 2 lost to start it)
Link reaction:
-Decarboxylation = 2 x CO2
-Oxidation = 2 NADH
Krebs cycle:
-Decarboxylation = 4 x CO2
-Oxidation = 6 NADH AND 2 FADH2
-ATP formation = 2 ATP (substrate level)
Electron transport chain:
-ATP formation = 32 ATP (oxidative phosphorylation)
Total:
-Decarboxylation = 6 CO2
– Net ATP formation = 36 ATP (38 total, 2 lost in glycolysis)
[a] light dependent reaction
light independent reaction (Calvin cycle)
[a] -Light photoactivates chlorophyll within photosystem II (P680) and photosystem I (P700)
-Electrons released from PSI are taken up by hydrogen carriers (forms NADPH)
-Electrons released from PSII go through an electron transport chain (causing proton accumulation in thylakoids)
-Protons return to the stroma via chemiosmosis through ATP synthase (producing ATP via photophosphorylation)
-Electrons lost from PSI are replaced by PSII electrons, while PSII electrons are replaced by photolysis of water
[a] Cyclic photophosphorylation:
Photosystems: PSI only
Products: ATP only
Purpose: cannot be used to make organic molecules
—————————————
non-cyclic photophosphorylation:
Photosystems: PSI and PSII
Products: ATP and NADPH
Purpose: Used to make organic molecules via light independent reaction (calvin cycle)
[a] -Carbon fixation: RuBP is carboxylated by CO2 to form two 3C compounds (GP)
-Reduction: GP is reduced by NADPH and reacts with ATP triose phosphate (TP)
-Regeneration: One TP molecule is used to make organic compounds, the rest are reacted with ATP to form RuBP
[a] -Calvin treated algae with radioactive carbon (14C) in a ‘lollipop’ apparatus
-Algae was then subjected to light to promote photosynthesis
-Algae was then killed (with alcohol) at different time periods and the carbon compounds were then extracted (via 2D chromatography) and then visualized (via autoradiography)
-This allowed Calvin to elucidate the order in which carbon compounds occurred (i.e. RuBP to GP to TP to RuBP)
[a] -on the upper surface of the leaf, the cells are packed tight and rich in chloroplasts
-This increases light absorption for photosynthesis
Remember P as top
[a] -on the lower surface of the leaf, the cells are interspersed by space and near stomata
-this increases gas exchange for photosynthesis
Remember S is on bottom
[a] -exists centrally between both layers (allowing equal access)
-contains xylem for water to leaf transport and phloem for food transport from leaf
remember it as the big red blocky circle
[a] monocot: less centered and bigger veins (bigger)
Dicot root: more centered and smaller veins (smaller)
[a] Monocot: less centered, with dots all over the place
Dicot: ringed, and has half circles on them
[a] -inner lining is composed of dead cells that have fused into a continues tube
-these cells lack a membrane, allowing water to enter the xylem freely
-the cell walls have thickened cellulose and are reinforced with lignin (annular or spiral)
-The outer layer is perforated (has pores), enabling water movement out of the xylem
[a] -protons pump expel H+ ions into the soil, displacing the cationic minerals from clay
-Displaced minerals will passively diffuse into the root (along a concentration gradient)
-Anionic minerals may bind to the H+ ions and be reabsorbed with the proton
[a] -Guard cells that flank the stomata can regulate the transpiration ate
-Guard cells occlude the opening when flaccid
-Abscisic acid regulates guard cell turgor
[a] -Some of the light energy the leaves absorb change into heat, converting water to vapor
-the vapor diffuses out and is evaporated, creating a negative pressure gradient in the leaves
-The xylem draws new water from roots (which enter from soil via osmotic uptake)
-Water rises up (against gravity) through xylem vessels via mass flow because of cohesion and adhesion
-The flow of water from the roots to the lead (via xylem) is called the transpiration system
[a] -increasing light intensity to which a plant is exposed increases the rate of transpiration
-increasing light exposure causes more stomata to open to facilitate photosynthetic gas exchange
[a] -Increasing ambient temp causes an increase to the rate of transpiration
-Higher temp leads to an increase in the rate of evaporation within the mesophyll
[a] -increasing the level of wind exposure causes an increase in the rate of transpiration
-Wind/air circulation removes water vapor from near the leaf, effectively reducing proximal humidity
[a] -increasing the humidity is predicted to cause a decrease in the rate of transpiration
-less vapor will diffuse from the leaf if there is more vapor in the air
[a] Conditions: arid/dry and high temps
Issues: increased water loss via evaporation. Reduced water uptake via roots
Adaptation: reduced leaves (lowers evaporation). Thick cuticles (prevent water loss). Stomata in pit (traps water vapor). CAM physiology (open stomata at night)
[a] conditions: saltine (salty soil/water)
Issues: reduced water uptake because of hypertonic. Soil conditions (high levels of salt uptake)
Adaptations: cellular sequestration (salt in vacuoles). tissue partitioning (lead abscission). Salt excretion (active salt removal). Root-level exclusion (avoid salt uptake)
[a] -Capillary tubing
-porous pots
-Filter paper
[a] -potometers estimate transpiration rate by measuring the rate of water loss or uptake by a plant
-they record the distance moved by an air bubble or meniscus to indicate the rate of water uptake
[a] -Phloem tubes are composed primarily of two main types of cells: sieve elements and companion cells
-Sieve elements are long, narrow cells connected by porous sieve, with no nuclei and reduced organelles
– companion cells sustain the sieve elements and possess an infolding plasma membrane to increase SA:Vol ratio
-Plasmodesmata connect the two cell types to mediate symplastic exchange
[a] -Moves materials via the process of transpiration
-Transports water and minerals unidirectionally
-xylem occupy the inner portion of the vascular bundle
-Vessel wall made of fused cells (continuous tube)
-Vessels are hollow with no cell content
[a] -moves materials via active translocation
-transports nutrients bidirectionally
-phloem occupy the outer portion of a vascular bundle
-vessel wall made of cells connected by sieve plates
-vessels are composed of living tissue
[a] -plants transport organic molecules from source (photosynthetic tissue) to sink (storage organs)
-these organic molecules are transported via a tube system called the phloem in a viscous fluid called sap
-organic molecules are are loaded / unloaded via companion cells (either by a symplastic or apoplastic pathway)
-active loading of solutes into phloem creates high concentration that draw water (from xylem) via osmosis
-Incompressibility of water causes the sap volume/pressure to increase resulting in mass flow
-Organic molecules are actively unloaded at the sink which causes water to return to the xylem
[a] -aphids are insects that feed on sap in phloem via a stylet (which can be severed to collect the sap)
-if plants are exposed to radioactive CO2, they will produce radioactively labelled sugars
-translocation rate can be identified by the time taken for radioisotopes to be detected at various points
[a] -Undifferentiated cells in plants capable of indeterminate growth (analogous to stem cells)
-Meristematic tissues have specific regions of growth in plants (allows regrowth of vegetative propagation)
[a] -Occurs at the tips of roots and shoots
-Responsible for primary growth (adds length)
-develops into primary xylem and phloem
-produces new leaves and flowers
[a] -Occurs at the cambium
-Responsible for secondary growth (width)
-Produces secondary xylem and phloem
-Produces the bark on trees
[a] -Auxin released by the apical meristem in shoots promotes apical growth
-It additionally inhibits growth in lateral buds (a condition called apical dominance)
-As shoots grow further from lateral buds, inhibition is diminished, allowing spread
Grows up, then out
[a] -Auxin efflux pumps set up concentration gradients of auxin in response to stimuli
-These pumps control growth direction by determining areas with high auxin levels
[a] -The turning of an organism in response to a directional external stimulus
Phototropism: growth response to light
Geotropism: growth response to gravity
[a] -Plant tropisms are caused by a differential elongation of cells in response to stimulus
-Auxin controls rates by changing patterns of gene expression in plant cells
-In shoots, auxin promotes cell elongation, while in roots, auxin inhibits cell elongation
-Plant turns away from side with cell elongation, so the shoots grow towards light (positive tropism) and the roots grow away from light (negative tropism)
[a] 1. tissue sample (explant) grown in nutrient agar
2. Development prompted by growth hormones
3. Growing shoots divided (multiplication phase)
4. Cloned plants transferred to new soil
————————————————————–
1. rapid bulking: cloning desirable stock plants
2. virus-free strains: cloning non-infection tissue
3. Propagation of rare species: prevents extinction
[a] -Most flowering plants will use mutualistic relationships with pollinators to reproduce
-The plant plants use a mechanism of pollen transfer, while the animal gains source of nutrition (ex: nector)
[a] -phytochrome exists in two forms: an inactive form (Pr) is predominant at night, while an active form (Pfr) is predominant during day (the active form triggers flowering and requires a critical night length)
-In long-day plants, Pfr activates flowering so flowering is induced when night is short (upped Pfr)
-In short-day plants, Pfr inhibits flowering so flowering is induced when night is long (lower Pfr)
[a] -Horticulturalists can manipulate flowering by controlling the exposure to light
-Short-day plants can be induced to flower by covering with black cloth for ~12 hrs a day
[a] -Germinating seeds require:
-oxygen (for ATP via aerobic respiration)
-water (to metabolically activate cells)
-temp. (for optimal enzyme activity)
-pH (suitable soil conditions for enzyme)
-In addition, particular species may require specialized conditions, such as fire, freezing, washing, and digestion
[a] -The process by which sex cells (gametes) are made in the reproductive organs
-It involves the reduction division o fa diploid germline cell into four genetically distinct haploid cells
[a] -Inheritance of one gene/trait is independent to the inheritance of other gene/trait
-Alleles can divide randomly of each other (with each at an equal chance), leading to more genetic variation
-As humans have a haploid number of 23, there are 2^23 gamete combination (over 8 million combinations)
-For example, if there are 2 blue alleles and 2 red alleles, there is an equal chance that the two blue alleles and two red alleles separate together into Metaphase II as is possible the red and blue pairs split with each other upon getting to Metaphase II
[a] -During Prophase I, homologous pairs of chromosomes connect via chiasmata (between non-sister chromatids) in a process called synapsis–the resulting complex is called a bivalent
-Chiasmata represent the point where genetic information has been exchanged (forming recombinants)
-Recombination through gene exchange produces new combinations of alleles
[a] -Chromosomes condense, nuclear membrane dissolves
-Homologous chromosomes form bivalents
-Crossing over occurs
[a] -group of genes whose loci are on the same chromosome
-Function as a single inheritable unit and do not follow independent assortment (aren’t likely to be inherited together during crossing over; other times they are)
-RIP Mendel 🙁
[a] -He undertook breeding experiments with Drosophila (fruit flies) and found a clear sex ( ͡° ͜ʖ ͡°) bias in the inheritance of certain traits
-Morgan determined that genes located on a shared chromosome would NOT independently assort (+ have non-Mendelian ratios)
[a] Ab/ab
AND
aB/ab
[a] -monogenic traits have a finite pattern of expression (i.e. discrete variation)
-Polygenic traits normally exhibit a bell-shaped distribution (i.e. continuous variations)
[a] 1. Human height
2. Skin color / pigmentation
[a] (the sum of) ((O-E)^2)/E
O = observed (what did you gather)
E = expected (what was expected)
[a] -Genetic drift is a change in composition of a gene pool because of random events; population size impacts it
-Size affects stability of allele frequencies (high drift in small populations / low drift in large populations)
[a] effects: intermediate phenotype is favored at the expense of both phenotypic extremes
Example: human birth weights (too large = birthing compilations; too small = risk of death)
[a] Effect: where one phenotypic extreme is selected at the cost of the other phenotypic extreme
Example: antibiotic resistance in bacteria (presence of antibiotic = resistance up)
[a] Effect: where both phenotypic extremes are favored at the expense of the intermediate phenotypes
Example: pigmentation of peppered moth (dark or light coloration for camouflage)
[a] -Occurs when two populations differ in their periods of activity or reproductive cycle
ex: leopard frogs and wood frogs reach sexual maturity at different times in the spring and hence cannot interbreed
[a] -occurs when two populations exhibit different specific courtship patterns
Ex: certain populations of crickets may be morphologically identical but only respond to specific mating calls
[a] -occurs when two populations occupy different habitats or separate niches within a common region
Ex: lion and tigers occupy different habitats and do not interbreed (usually)
[a] -evolutionary process that results in the formation of new species from pre-existing species
-occurs when reproductive isolating mechanisms prevent two organisms from producing fertile offspring
[a] -Occurs when a geographical barrier physically isolates populations of an ancestral species
-the two populations begin to genetically diverge until they can no longer interbreed (speciation)
[a] -Divergence of species within the same geographical location (no physical barrier)
-reproductive isolation may be a result of genetic abnormalities (ex: chromosomal errors)
[a] -Sympatric speciation is most commonly caused as the result of a meiotic failure during gamete formation
-I meiotic cells fail to undergo cytokinesis, chromosomal number will double in the gamete (diploid not haploid)
-This results in offspring that has an additional set of chromosomes (polyploidy)
-Speciation will result if the polyploid offspring are fertile but cannot interbreed with the parent population
-More common in plants that can self-fertilize and reproduce asexually (vegetative propagation)
[a] -Speciation occurs following continuous change at a constant pace over a long period of time
-Arises via a gradual accumulation of mutations (big changes result from many small changes)
[a] -Speciation occurs rapidly in bursts with long periods of stability in between
-In stable periods, characteristics are maintained, but this is punctuated by periods of environmental change
[a] Ancestral relatedness: species do NOT share a common ancestry
Evolutionary effect: adopt similar phenotypic features because of shared selection pressures
type of adaptation: analogous structures
[a] ancestral relatedness: species share a common ancestry
Evolutionary effects: adopt dissimilar phenotypic features because of different selection pressures
type of adaptation: homologous structures
[a] Direct contact: transfer of pathogens via physical association
Exchange of body fluids: from blood transfusions or sexual intercourse ( ͡° ͜ʖ ͡°)
Contamination: infestations of pathogens growing on, or in, edible food sources
Airborne: certain pathogens can be transferred in the air via coughing and sneezing
Vectors: intermediary organisms that transfer pathogens without developing symptoms themselves
Acronym: Driven Elves construct automated vans
[a] -Disease from animals that can be transmitted to humans are called zoonotic diseases (or zoonoses)
-Ex: rabies (dog), some strains of influenza (bird flu) and bubonic plague (fleas on rats)
[a] Antigen: substance that the body recognizes as foreign and that will elicit an immune response
Antibody: proteins produced by lymphocytes that recognize and neutralize specific antigens
[a] Antigen on blood cell:
Type A: A antigen
Type B: B antigen
Type AB: both A and B antigen
Type O: No antigen
Antibodies in bloodstream:
Type A: anti-B antibody
Type B: anti-A antibody
Type AB: no antibodies
Type O: Anti-A and Anti-B antibodies
Blood donors:
Type A: can take A or O, but not B or AB
Type B: can take B or O, but not A or AB
Type AB: Can take any (universal acceptor)
Type O: Can only take O (universal donor)
[a] MHC I:
where found: all nucleated body cells (not RBCs)
Antigens presented: endogenous antigens
cells presented to: cytotoxin T cells (and TH cells)
MHC II:
Where found: antigen-presenting cells (ex: macrophages, B cells)
Antigens presented: exogenous antigens
Cells presented to: B cells (and TH cells)
[a] -The pathway by which antibodies are produced by plasma cells to target exogenous antigens
-Antigens are presented on the MHC class II markers of macrophages to helper T cells
-The helper T cells then secrete cytokines to activate the appropriate B lymphocytes
-The specific B cells divide and differentiate (clonal selection) to form antibody producing plasma cells
[a] -The pathway that does not result in antigen production but instead targets endogenous antigens
-Cancerous and virus-infected cells involve the body’s own cell and thus are not recognized as foreign
-These cells present antigenic fragments as a complex with their own self markers (MHC class I)
-When helper T cells identify these cells, they stimulate cytotoxic T cells that lyse the compromised cells
[a] Precipitation: soluble pathogens become insoluble and precipitate
Agglutination: Cellular pathogens become clumped for easier removal
Neutralization: antibodies may occlude pathogenic regions
Complement activation: complement proteins perforate membranes
Acronym: PANIC
-Collectively, the actions of antibodies enhance the immune system by aiding the detection (opsonization) and removal of pathogens by the phagocytic leukocytes of the innate immune system (macrophages)
[a] -When a B lymphocyte divides to form plasma cells, a small portion will differentiate into memory cells
-Memory cells are long living and survive many years, producing low levels of circulating antibodies
-If re-infection occurs, memory cells produce antibodies faster so disease does not develop (immunity)
[a] -contain attenuated forms of a pathogen that cannot cause disease
-vaccinations induse active immunity by stimulating production of memory cells
-When exposed to actual pathogen. the memory cell is triggered faster/stronger secondary immune resources
[a] 1. Easily identifiable
2. Infection period short and virus was stable (not mutating)
3. Transmission required direct contact and there were no animal vectors or reservoirs to sustain the virus
[a] -An animal (ex: mouse) is injected with antigen to produce specific plasma cells
-Plasma cells are removed and fused with tumor cells capable of endless divisions
-The resulting hybridoma will synthesize large quantities of the specific antibody (monoclonal)
[a] diagnostic: detection of pregnancy (anti-hCG antibody)
Therapeutic: treatment of cancer or rapid infection (ex: rabies)
[a] muscles can only cause movement by contracting (i.e. muscles cause movement in one direction)
-To enable opposing movements, muscles must work in antagonistic pairs (resets bone back to its original position)
[a] -Skeletal muscles consist of bundles of muscle fibers (formed of fused cells) that have key characteristics
-Multinucleated: muscle fibers are formed from multiple individual muscle cells fusing together
-Large number of mitochondria: contractions requires a lot of mitochondria
-Tubular myofibrils: Tubular myofibrils run the length of the fiber and are responsible for contraction
-Sarcolemma: The sarcolemma is the continuous membrane surrounding a muscle fiber
-Sarcoplasmic reticulum: internal membrane network that is specialized for muscle contractions (high calcium)
[a] -Action potential in a motor neuron triggers the release of Ca2+ ions from the sarcoplasmic reticulum
-Calcium molecules bind to troponin (on actin) and cause tropomyosin to move, exposing binding sites for myosin heads
-The actin filaments and myosin heads form a cross-bridge that is broken by ATP
-ATP hydrolysis causes the myosin heads to swivel and change orientation
-Swiveled myosin heads bind to actin filament before returning to their original conformation (releasing ADP)
-Repositioning of the myosin heads move the actin filaments towards the center of the sarcomere
-The sliding of actin along myosin therefore shortens the sarcomere, causing muscle contractions
[a] -Relaxed if there is a visible H band and wide I band
-Contracted if there is a narrow I band and no H zone
[a] Mammals possess autonomous kidneys
insects possess Malpighian tubules that are connected to the insect’s digestive system
[a] match their internal osmolarity to that of their environment
Ex: fish
[a] maintain a constant osmolarity, independent of environment
ex: people
[a] -occurs in glomerulus / bowman’s capsule
-Non-specific filtration of blood under high pressure (separates blood cells and proteins)
-Glomerular capillaries are fenestrated and the capsule is lined with podocytes that have extensions
-Blood freely enters the capsule by passing between the extensions, so the only barrier is a basement membrane
-Blood enters the glomerulus via a wide afferent arteriole and exits via a narrow efferent arteriole
-This makes it difficult for blood to exit the glomerulus, increasing the hydrostatic pressure in the glomerulus
[a] -located in the convoluted tubules (mainly proximal but sometimes distal)
-involves the reuptake of usable substances from filtrate
-substances are actively transported across apical membrane before diffusing across basolateral membrane
-Tubules are lined by microvilli (increased SA) and reabsorb the following materials: glucose and amino acids (symport with Na+), ions and vitamins (via protein pumps), water (follows via osmosis)
[a] -Loop of Henle creates a salt gradient within the medulla
-Descending limb is permeable to water but not salt
-Ascending is inverse
-Means as the loop descends into the medulla, the interstitial fluid becomes salty (hypertonic)
-Additionally, blood in the vasa recta runs countercurrent to the filtrate, so salts in blood move towards the medulla (and water away)
-as the collecting duct passes through the medulla, the salt gradient will draw water from the ducts (osmoregulation)
[a] -Level of water drawn from collecting duct is controlled by the hormone antidiuretic hormone (ADH)
-ADH is released from the pituitary gland (posterior lobe) in response to dehydration
-ADH produces water channels (aquaporins) to facilitate water reabsorption via osmosis
-This means less water remains in the filtrate and the urine becomes more concentrated
-when an individual is suitably rehydrated, ADH levels decrease and less water is reabsorbed
[a] blood: present
Filtrate: absent
urine: absent
Remains in blood because of ultrafiltration
[a] blood: present
filtrate: present
urine: absent
reason: it’s selectively reabsorbed in tubules
[a] blood: present
filtrate: present
Urine: present
Reason: eliminated as a nitrogen waste product
[a] blood: present
filtrate: present
Urine: present
reason: variable excretion to regulate water levels in body (osmoregulation)
[a] glucose: indicates diabetes
Protein: certain diseases / hormonal conditions
[a] -Kidney dialysis involves the external filtering of blood to remove metabolic waste
-Blood is pumped through a dialyzer, which restricts passage of certain materials and introduces fresh fluid
-The best long-term treatment for kidney failure is a kidney transplant
-A transplanted kidney is grafted into the abdomen, but donors must be a close genetic match to minimize rejection
[a] -involves mitosis followed by cell growth followed by meiosis (two divisions) and differentiation
-Occurs in seminiferous tubules (testes) and produces four gametes per germ cell
-Gametes differentiate into spermatozoa via a process that occurs continuously from puberty
[a] 1. Primordial follicle
2. Primary follicle
3. secondary follicle
4. Graafian follicle (mature)
5. oocyte
6. corpus luteum
7. corpus albicans
[a] -occurs in ovaries (completed in oviduct), with only one gamete produced per germ cell
-There is unequal division of cytoplasm (forms one egg and up to three polar bodies)
-Occurs in staggered stages (fetal development -> puberty -> fertilization)
[a] -Process begins during fetal development, when a large number of primordial cells are formed by mitosis
-Primary oocytes remain arrested in prophase I until puberty, when a girl begins her menstrual cycle
-Each month, hormones unlock some oocytes to begin the second meiotic division (but are arrested in metaphase II)
-If the oocyte is fertilized by a sperm, meiosis II is completed and the mature egg form an ovum
[a] Spermatogenesis:
number of gametes produced: 4
Cytoplasmic division: equal
Duration of process: continuous
Timing of gamete release: lifelong (from puberty)
Oogenesis:
Number of gametes produced: 1 (+ polar bodies)
Cytoplasmic divisions: unequal
Duration of process: in staggered stages
Timing of gamete release: finite (menarche to menopause)
[a] -biochemical changes occur when sperm enters the female reproductive tract
-Uterine chemicals dissolve the sperm’s cholesterol coat, improving its motility
[a] -to enter the egg, sperm must penetrate the protective jelly coat (zona pellucida)
-Acrosome vesicles release enzymes which soften the glycoprotein matrix
-Egg and sperm membranes fuse and the sperm nucleus (+ centriole) enter the egg
[a] -cortical granules release enzyme that destroy sperm-binding proteins on the jelly coat (after fertilization)
-Prevents other sperm from penetrating the fertilized egg (polyspermy)
[a] -when a blastocyst is implanted into the endometrium it begins to secrete hCG (human chorionic ganadotropin)
-hCG sustains the corpus luteum and prevents its degeneration (continues to make estrogen and progesterone)
-Estrogen inhibits FSH and LH, preventing further egg release, while progesterone maintains the endometrium
-When a placenta develops and begins to produce progesterone, hCG levels drop and he corpus luteum degenerates
[a] -Zygote undergoes several divisions to form a morula and subsequent unequal divisions results in a blastocyst
-Blastocyst contains an inner cell mass (forms embryo), outer layer (trophoblast: forms placenta) and a cavity
-Occurs in the oviduct and when the blastocyst reaches the uterus, it embeds into the endometrium
[a] -The placenta is a disc-shaped structure that nourishes the developing embryo
-It is formed from the trophoblast of a developing embryo (outer layer)
-An umbilical cord connects a fetus to the placenta and maternal blood pools via open-ended arterioles into lacunae
-Fetal chorionic villi extends into these lacunae and facilitate maternal exchange
[a] maternal -> fetal: nutrients, O2, and maternal antibodies will be taken up by fetus
Fetal -> maternal: CO2 and toxic waste (ex: urea) will be removed by mother
[a] -Placenta takes over hormonal role as corpus luteum degenerates
-Estrogen stimulates growth of the uterine myometrium and mammary glands
-progesterone maintains the endometrial lining and reduces uterine contractions
[a] -The fetus begins to stretch the uterine walls, which trigger the release of two hormones: oxytocin and estrogen
-Estrogen inhibits progesterone (which was preventing contractions) and oxytocin stimulates uterine contractions
-As the uterus contracts, stretch receptors are further stimulated (positive feeback)
-Contractions will stop when the baby is birthed (no more stretching of the uterus)
[x] Exit text
[/qdeck]