IB DP Biology HL Flashcards All Topics

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[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)


-R
eplace 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”)

 
[q] How does the solubility of molecules affect their mode of transport within the blood

[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)

 
[q] Outline structural organization of carbs (monomer -> polymer)

[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)

 
[q] Three examples of monosaccharides, disaccharides and polysaccharides

[a] Monosaccharides: Glucose, Glactose, Fructose (good flavor 🙂

Disaccharides: Lactose, sucrose, Maltose (length supports movement)

Polysaccharides: Cellulose, Glycogen, starch (hint: can be stored)

 
[q] Three functions of carbs in cells

[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

 
[q] Cellulose

[a] Monomer: B-glucose

Bonding: 1-4 linkages

-Shape: Linear (sheets)

 

-Function: structural components of plant cell walls

 
[q] Amylose

[a] Monomer: a-glucose

Bonding: 1-4 linkages

Shape: linear (helical)

-short term energy storage in plants (type of starch)

 
[q] Amylopectin

[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)

 
[q] Glycogen

[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

 
[q] Differentiate between the 3 classes of lipids

[a] -Simple lipids: Triglycerides

-Compound lipids: phospholipids, sphingolipids, etc

-Derived lipids: steroids, cholesterol

 
[q] Five different functions of lipids

[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

 
[q] Compare the use of carbs and lipids as an energy source

[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

 
[q] Why are carbs and lipids better than proteins for an energy source

[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)

 
[q] saturated and unsaturated fatty acids

[a] Saturated: lack a double bond (possess maximal amount of H atoms)

 

Unsaturated: fatty acids possess double bonds (may be monounsaturated or polyunsaturated)

 
[q] Cis isomers

[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

 
[q] Trans isomer

[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

 
[q] High density v low density lipoproteins

[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

 
[q] Effects of different types of fatty acids on lipoprotein levels

[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

 
[q] Health implications of high levels of blood cholesterol

[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)

 
[q] Discuss evidence for and against health risks associated with diets rich in lipids

[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

 
[q] Describe the basic structure of a generalized amino acid

[a] -Amine group on the left

 

-Variable (R) group on the bottom

 

-Carboxyl group on the right

 

-hydrogen on top

 

-Carbon in the middle

 
[q] Outline structural organization of a polypeptide chain (monomer -> polymer)

[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

 
[q] Show a basic structure of a generalized dipeptide

[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

 
[q] How many different amino groups are there and how are they different?

[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

 
[q] Different levels of protein folding

[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.

 
[q] seven functions of protein, providing an example for each

[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

 
[q] Denurturation
[a] A loss of protein structure resulting in loss of biological activity
 
[q] two factors in denaturation

[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

 
[q] relationship between genes and polypeptides

[a] -Genes are sequences of DNA that encode polypeptides

 

-Typically, one gene equals one polypeptide–however, exceptions exist (ex: tRNA genes)

 
[q] Proteome
[a] The totality of proteins expressed within a cell, tissue, or organism at a given time
 
[q] enzyme
[a] A globular protein that speeds up the rate of a chemical reaction by lower the activation energy (biological catalyst)
 
[q] Substrate
[a] A compound that binds to an enzyme’s active site and is converted into a product (the substrate is complementary in shape and chemical properties to the active site)
 
[q] Steps in enzymatic binding and catalytic activity

[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)

 
[q] Factors that can affect an enzyme’s molecular motion and collision with a substrate

[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

 
[q] Lock and key model
[a] Substrate and active site are complementary in both shape and chemical properties. Enzymes are specific for reactions they catalyze.
 
[q] induced fit model
[a] Active site is not a perfect fit, but undergoes a confrontational change in shape to accommodate substrate. This stresses bonds in the substrate and gives rise to broad specificity.
 
[q] temperature on enzyme activity

[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

 
[q] pH on enzyme activity

[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.

 
[q] Substrate concentration on Enzyme activity

[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.

 
[q] benefits of immobilized enzymes in industry, with examples

[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

 
[q] production of lactose-free milk and its benefits

[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)

 
[q] Suggest ways of measuring enzyme-catalyzed reactions: conversion of hydrogen peroxide to oxygen gas by catalase:

[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

 
[q] Suggest ways of measuring enzyme-catalyzed reactions: the breakdown of starch into maltose (by diastase)

[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)

 
[q] Suggest ways of measuring enzyme-catalyzed reactions: digestion of pectin in cell walls (by pectinase)

[a] -Measuring volume of liquid produced as a consequence of the breakdown in cell wall

 

-measure the digestion of pectin via percentage weight change

 
[q] nucleotide structure
[a] 5 carbon sugar, phosphate group, nitrogenous base
 
[q] four different types of basis in nucleic acids

[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

 
[q] DNA

[a] Sugar: Deoxyribose

Bases: G, C, A, T

Strands: double stranded

 
[q] RNA

[a] Sugar: ribose

Bases: U, A, C, G

Strands: one (usually)

 
[q] Three types of RNA

[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

 
[q] How are nucleotides linked together to form DNA strands

[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.

 
[q] Scientists that contributed to the elucidation of DNA structure

[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

 
[q] How did Watson and Crick propose the structure of DNA via model making

[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

 
[q] How is DNA replication semi-conservative?

[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)

 
[q] How do the results of Meselson-Stahl’s experiment support semi-conservative DNA replication

[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

 
[q] Helicase in DNA replication

[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

 
[q] DNA polymerase

[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

 
[q] Significance of complementary base pairing in conservation of base sequences

[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

 
[q] Where does DNA replication happen
[a] In the nucleus during S phase
 
[q] Purpose and process of the polymerase chain reaction (PCR)

[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.

 
 
[q] Transcription
[a] The process which RNA sequences are produced from DNA templates (gene)
 
[q] Sense v antisense strands

[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)

 
[q] Role of RNA polymerase in the process of transcription

[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

 
[q] translation
[a] process of protein synthesis, whereby genetic information encoded in the mRNA is translated into an amino acid sequence at the ribosome
 
[q] function of the genetic code

[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)

 
[q] Key components of translation

[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

 
[q] Process of translation

[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

 
[q] different mutations

[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

 
[q] Frameshift mutation
[a] This mutation changes the reading of a frame, causing the codons to all be changed, resulting in a completely different protein than the one coded
 
[q] This mutation changes the reading of a frame, causing the codons to all be changed, resulting in a completely different protein than the one coded

[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

 
[q] cell respiration
[a] controlled release of energy from organic compounds to produce ATP
 
[q] How is ATP acting as the energy currency for cells

[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

 
[q] anaerobic respiration

[a] -Oxygen not required

 

-Only 2 ATP yield

 

-products:

 

-Animals: Lactic acid

Plants: ethanol and CO2

Location: Cytosol

 
[q] Aerobic respiration

[a] -Oxygen required

 

-High yields (36-38 ATP)

 

-Products: CO2 and H2O

 

-Happens in the Cytosol and mitochondria

 
[q] Purpose and products of fermentation

[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+)

 
[q] Use of respirometry in measuring respiration rates

[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)

 
[q] Photosynthesis
[a] process by which cells use light energy to synthesize organic compounds from inorganic molecules
 
[q] what is the range of wavelengths absorbed via photosynthesis
[a] photosynthesis uses the visible spectrum (white light), which ranges from 400nm to 700nm
 
[q] Main photosynthetic pigment in plants and where it is found
[a] Chlorophyll is the main pigment, and is found in chloroplast in plants
 
[q] Difference in absorbed red, green, and blue light by plants
[a] plants predominantly absorb red and blue light, but reflects green light
 
[q] Action spectrum and absorption spectrum

[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.

 
[q] light-dependent reaction

[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

 
[q] Light-independent reaction

[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)

 
[q] How can photosynthetic pigments be separated through chromatography

[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

 
[q] Law of limiting factors
[a] A reaction will only proceed as fast as the component nearest its minimum value (rate-limiting factor)
 
[q] A reaction will only proceed as fast as the component nearest its minimum value (rate-limiting factor)
[a] Measure by pressure change (data logger) or displacement of syringe cap
 
[q] Conditions which photosynthesis can be detected and how they can be measured: CO2 production
[a] Measure by a change in pH if plant is in solution (CO2 dissolves in water to form carbonic acid–that decreases pH)
 
[q] Conditions which photosynthesis can be detected and how they can be measured: change in biomass
[a] Measure by a change in weight (plant sample must first be desiccated to account for change in mass because of water)
 
[q] Effects of different factors on the rate of photosynthesis: temperature

[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

 
[q] Effects of different factors on the rate of photosynthesis: light intensity

[a] -Increasing light levels result in more photoactivation of chlorophyll (= increased activity)

 

-At a certain intensity, all chlorophyll are photoactivated and so activity plateaus

 
[q] Effects of different factors on the rate of photosynthesis: CO2 concentration

[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

 
[q] Gene
[a] A section of DNA that codes for a particular characteristic (via production of specific proteins)
 
[q] Locus
[a] The specific location of a gene on a particular chromosome
 
[q] Allele
[a] An alternate form of a gene
 
[q] An alternate form of a gene
[a] see Bioninja’s website on topic 3.1’s note packet for this activity
 
[q] genome
[a] totality of genes in a cell, organism, or organelle
 
[q] three potential applications of the completed Human Genome Project

[a] -Screening for known genetic conditions

 

-Discovering new drug treatments and medications (ex: phamacogenomics)

 

-Establishing ancestral lineage

 
[q] Three types of mutagens

[a] 1. Physical (ex: radiation)

 

2. Chemical (ex: tobacco and other carcinogens)

 

3. Biological (certain viruses)

 
[q] Somatic versus germline mutation

[a] Stomatic: affects body cells and cannot be inherited by offspring

 

Germline: Affects sex cells and will be passed onto offspring

 
[q] Consequences of base substitution mutation and the development of sickle cell anemia

[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)

 
[q] Prokaryotic chromosome structure

[a] -DNA is circular

 

-DNA is naked (not bounded to proteins)

 

-Single chromosome (called the genophore)

 

-found in the nucleoid region of the cytosol

 
[q] Eukaryotic structure of a chromosome

[a] -DNA is linear

 

-DNA is bound to histone proteins

 

-Chromosome may exist in pairs (diploid)

 

-Found in the nucleus

 
[q] Role of plasmids in bacterial cells

[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

 
[q] How did John Cairns elucidate the length of chromosomes via autoradiography

[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

 
[q] Homologous chromosomes

[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

 
[q] Autosome
[a] Represent non-sex-related chromosomes
 
[q] Sex chromosome
[a] chromosomes that determine sex
 
[q] Diploids
[a] Nuclei passes pairs of homologous chromosomes (ex: body cells = 2n)
 
[q] Haploid cells
[a] This nuclei possesses only one copy of each chromosome (ex: gametes = n)
 
[q] Importance of chromosome number to the reproduction of a species

[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)

 
[q] Meiosis
[a] Reduction division of a diploid cell to produce four haploid daughter cells
 
[q] Meiosis I

[a] -Involves the separation of homologous chromosomes (bivalent / tretrads)

 

-Reduction division (diploid to haploid)

 

-Promotes genetic variation (crossing over and random assortment)

 
[q] Meiosis II

[a] -Involves separation of sister chromatids

 

-Is a mitotic division (haploid to haploid)

 

-Does not promote genetic variation

 
[q] Homologous chromosomes versus sister chromosomes

[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)

 
[q] Meiosis v mitosis

[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

 
[q] How does crossing over give rise to infinite genetic variety?

[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

 
[q] How does Independent Assortment give rise to infinite genetic variety

[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)

 
[q] how does random gamete fusion promote variation within a species

[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)

 
[q] how can non-disjunctions give rise to aneuploidy

[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

 
[q] genetic conditions that cause Down Syndrome and identify contributing factors

[a] -Trisomy 21 causes it

 

-increased maternal age increases risk of non-disjunction

 
[q] The method which cells are obtained for karyotyping

[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

 
[q] benefits and risks with amniocentesis

[a] -Cells are extracted from the amniotic fluid

 

-Occurs later in the pregnancy (~15 weeks) but has a slightly lower risk of miscarriage (~.5%)

 
[q] Benefits and risks of chorionic Villi sampling

[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%)

 
[q] Methodology and conclusions drawn from Mendel’s pea plant experiment

[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)

 
[q] Sexual reproduction results in diploid zygotes with two alleles for each characteristic

[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

 
[q] Homozygous
[a] Alleles are the same for a given characteristic
 
[q] Heterozygous
[a] Alleles are different for a given characteristic
 
[q] Hemizygous
[a] There is only one allele (occurs in males for sex chromosome ( ͡° ͜ʖ ͡°) traits)
 
[q] Complete dominance
[a] One allele (dominant) masks expression of other allele (recessive) in heterozygotes
 
[q] codominance
[a] both alleles are expressed within a heterozygous phenotype
 
[q] genotypes of blood
[a] here’s that map
 
[q] Which blood group is the universal donor and acceptor

[a] -O is the universal donor

 

-AB is the universal acceptor

 
[q] sex linkage ( ͡° ͜ʖ ͡°) and two examples

[a] -any gene/trait that is located on the sex chromosome ( ͡° ͜ʖ ͡°)

 

-Example 1: Hemophilia

 

example two: red-green color blindness

 
[q] Why are X-linked disorders more common in males?
[a] Males only have one X chromosome and so cannot be carriers for recessive conditions
 
[q] how is cystic fibrosis linked to inheritance

[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

 
[q] how is huntington’s disease linked to inheritance

[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

 
[q] health consequences of Hiroshima and Chernobyl

[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)

 
[q] purpose and process of the polymerase chain reaction (PCR)

[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

 
[q] Purpose and process of gel electrophoresis

[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)

 
[q] Fragments
[a] Larger fragments move more slowly though gel matrices and hence do not travel as far
 
[q] Two types of vectors for gene transfer

[a] -Plasmids

 

-Viruses

 
[q] ‘blunt’ and ‘sticky end’ restriction endonucleases
[a] sticky ends are overhanging sequences which allow for specificity in ligation (only complementary sequences can ligate together) — blunt ends have no overhang
 
[q] process of gene transfer

[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

 
[q] role short tandem repeats (STRs) play in DNA profiling)

[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

 
[q] Two potential applications of DNA profiling

[a] -Forensic investigations

 

-Paternity testing

 
[q] Benefits and risks associated with the use of genetically modified crops

[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

 
[q] clone
[a] group of genetically identical cell or organism
 
[q] four methods of natural cloning

[a] -Budding (ex: yeast)

 

-Binary fission (hydra)

 

-Fragmentation (starfish)

 

-Parthenogenesis (some fish species)

 
[q] how are stem cuttings used to clone plants

[a] -Plants retains pluripotent cells (called meristem) and can reproduce asexually via vegetative propagation

 

-hence new plant clones can be grown from stem cutting

 
[q] how can organisms be cloned artificially?

[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.

 
[q] Abiotic factors
[a] Non-living chemical and physical factors in an environment (which affects ecosystem)
 
[q] biotic factors
[a] living components of an environment which affect an ecosystem
 
[q] Species
[a] A group of organisms that can potentially interbreed to produce fertile viable offspring
 
[q] population
[a] a group of organisms of the same species that are living in the same area at the same time
 
[q] community
[a] A group of populations living together and interacting with each other within a given area
 
[q] habitat
[a] the environment in which a species normally lives, or the location of a living organism
 
[q] ecosystem
[a] a community AND its abiotic environment (ex: habitat)
 
[q] nutrient

[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

 
[q] autotroph

[a] Synthesize their own organic molecules from simple inorganic substances (ex: CO2, nitrates)

 

-Energy derived from sunlight OR oxidation of molecules

 
[q] heterotrophs
[a] Obtain their organic molecules form other organisms
 
[q] Consumer
[a] Ingest organic molecules from living or recently killed organisms
 
[q] detrivore
[a] ingest organic molecules found in non-living remnants of organisms
 
[q] decomposer
[a] release digestive enzymes and then absorb the external products of digestion
 
[q] fate of energy and nutrients in an ecosystem

[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

 
[q] Role of decomposers in maintaining nutrient supplies

[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)

 
[q] Mesocosm
[a] An enclosed environment that allows a small part of the natural environment to be viewed under controlled conditions
 
[q] two methods of population sampling

[a] -Quadrats

 

-Transects

 
[q] Trophic level

[a] -The position of an organism occupies within a feeding source

 

-Producers always occupy the first level

 
[q] Food chain v food web

[a] Food chain: linear feeding relationship between species in a community

 

Food web: multiple food chains all in one place

 
[q] Arrows in food chains/webs
[a] The direction of energy
 
[q] Herbivore
[a] feeds exclusively on plant matter
 
[q] carnivore
[a] feeds exclusively on animal matter
 
[q] omnivores
[a] feeds on both plant and animal matter
 
[q] initial source of energy for almost all communities
[a] light (from the sun)
 
[q] how efficient are most biological energy transfers
[a] most energy transformations are only ~5-20%
 
[q] List three ways in which energy may be lost from one trophic level to the next

[a] -Heat

 

-Converted into another form of energy

 

-Stored chemical energy remains unconsumed

 
[q] Flow of energy in an ecosystem

[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

 
[q] why are energy pyramids shaped as pyramids?

[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

 
[q] Unit of measurement in pyramids of energy
[a] kJ (kilojules)
 
[q] biomass
[a] the total dry weight of organic matter in organisms or ecosystem
 
[q] carbon cycle
[a] see bioninja topic 4.3 for the diagram
 
[q] Photosynthesis equation
[a] 6CO2 + 6H2O ——> C6H12O6 + 6O2
 
[q] Cell respiration equation
[a] C6H12O6 + 6O2 ——> 6CO2 + H2O + energy
 
[q] How is carbon stored in aquatic ecosystems

[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)

 
[q] production of methane by methanogens and its oxidation in the atmosphere

[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

 
[q] formation of fossil fuel: peat/coal

[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

 
[q] formation of fossil fuels: oil/natural gasses

[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

 
[q] combustion of hydrocarbons

[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)

 
[q] Three human activities that trigger carbon fluxes

[a] Combustion of fossil fuels

 

deforestation

 

agricultural practices (produces methane gases)

 
[q] most common greenhouse gas
[a] water vapor
 
[q] four greenhouse gases
[a] CO2, Methane, nitrogen oxides, fluorinated gases (e.g. CFCs)
 
[q] Two main factors that determine the impact of greenhouse gases

[a] -Ability to absorb long-wave radiation

 

-Concentration within the atmosphere (determined by rate of release and persistence)

 
[q] Changes in atmospheric CO2 levels detected at the Mauna Loa observatory
 

[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

 
[q] relationship between greenhouse gases and the greenhouse effect

[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

 
[q] Three climate conditions that greenhouse gases influence

[a] -Global temps

 

-Weather conditions (more frequent extreme conditions)

 

-Ocean currents (changes can cause longer el niño events)

 
[q] relationship between CO2 levels and temp

[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)

 
[q] How do increasing concentrations of atmospheric CO2 threaten coral reefs

[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

 

 
[q] Two arguments against human-induced climate change and counterpoints to each

[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

 
[q] Evolution

[a] -The cumulative change in the heritable characteristics of a population

 

-A change in the allele frequency of a gene pool across successive generations

 
[q] Lamarck’s theory of evolution

[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

 
[q] Darwin’s theory of evolution

[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

 
[q] Natural selection
[a] Occurs when the environment determines which adaptations are beneficial or detrimental
 
[q] Artificial selection

[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

 
[q] Evidence for evolution provided by the fossil record

[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)

 
[q] process of fossilization

[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

 
[q] evidence for evolution provided by selective breeding

[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

 
[q] How are pentadactyl limbs of vertebrates providing evidence of evolution

[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

 
[q] how does natural selection lead to evolution

[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)

 
[q] Three primary sources of genetic variation

[a] Gene mutations

 

Meiosis (crossing over and independent assortment)

 

Sexual reproduction (random fusion of sperm and egg)

 
[q] three examples of selection pressure

[a] biotic factors (predators/pathogens)

abiotic factors (weather events, nutrient supply, etc)

random phenonena (fires, floods, earthquakes, etc)

 
[q] Structural adaptation
[a] Physical difference (ex: neck length of a giraffe)
 
[q] behavioral adaptation
[a] differences in activity patterns (ex: opossums feigning death when threatened)
 
[q] Psychological adaptation
[a] differences in responses to vital organs (ex: homeothermy, color perception)
 
[q] biochemical adaptation
[a] differences in molecular composition/enzyme functions (ex: blood groups, lactose intolerance)
 
[q] Adaptive radiation

[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

 
[q] Explain how evolution occurred in the peppered moth population of England during the industrial revolution

[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)

 
[q] antibiotic resistance and how they lead to evolution

[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

 
[q] Evolutionary changes of the beaks of Darwin’s finches

[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)

 
[q] bionomial system of nomenclature
[a] globally recognized classification scheme whereby every organism has a two-part scientific name: genus is written first and capitalized (ex: Homo) and species following it in lower case (ex: Homo sapiens)
 
[q] Three domains of life

[a] -eukarya (all eukaryotic organisms)

 

-Archaea (prokaryotic extremophiles)

 

-Eubacteria (common pathogenic bacteria)

 
[q] Seven levels of hierarchy of taxa

[a] Kingdom, phylum, class, order, family, genus, species

 

Acronym: Katy Perry Comes Over For Gay Sex

 
[q] Different methods of biological classification: natural

[a] -Groups organisms based on similarities first and then identify shared characteristics

 

-Shows how closely related organisms are and allows determination of evolutionary links

 
[q] Different methods of biological classification: artificial

[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

 
[q] Different methods of biological classification: phylogenetic

[a] -Differentiates organisms based on sequence similarities (genetics)

 

-Organisms with a greater similarity in DNA or amino acid sequences are more closely related

 
[q] bryophyta

[a] -no ‘true’ leaves, roots, nor stems

 

-no vascularization (no xylem/phloem)

 

-spores in capsule at the end of stalk

think: moss

 
[q] Filincinophyta

[a] -have vascularization

 

-spores in sporandia on underside of leaf

 

-have large fronds divided into leaves

 

Think: filin sounds kinda like fern

 
[q] coniferophyta

[a] -have vascularization

 

-have seeds (found in cones)

 

-leaves narrow with a thick, waxy cuticle

 

Think: literally has ‘cone’ in it

 
[q] angiospermophyta

[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

 
[q] Four plant phyla easy identification
[a] big fillups cost a-lot
 
[q] porifera (invertebrate)

[a] -possess an asymmetrical body plan

 

-having no mouth or anus (have pores)

 

-May have structural support

ex: sea sponge

 
[q] cnidaria (invertebrate)

[a] -Possess radial symmetry

 

-Have mouth but no anus (single opening)

 

-Has tentacle and stinging cells (cnidocytes)

Ex: cool-looking jelly

 
[q] platyhelmintha (invertebrate)

[a] -possess bilateral symmetry

 

-Have mouth but no anus (single opening)

 

-Flattened body increass SA:Vol ratio

Ex: flatworm

 
[q] annelida (invertebrate)

[a] -possess bilateral symmetry

 

-have separate mouth and anus

 

-body composed of rings segments

Ex: worms

 
[q] Mollusca (invertebrate)

[a] -possess bilateral symmetry

 

-have a separate mouth and anus

 

-may have shell

ex: octopus

 
[q] Anthropoda (invertebrate)

[a] -possess bilateral symmetry

 

-have a separate mouth and anus

 

-have jointed appendages and exoskeleton

ex: scorpions

 
[q] Fish (vertebrate)

[a] -covered in scales (bony plate of skin)

 

-Reproduce via external fertilization

 

-breathe through gills

-Are ectothermic

 
[q] amphibian (vertebrate)

[a] -have moist skin, permeable to gases

 

-reproduce via external fertilization

 

-breathe via skin (may have simple lungs)

-are ectothermic

 
[q] reptiles

[a] -covered in scales (made of keratin)

 

-have internal fertilization (lay soft eggs)

 

-breathe via lungs (with extensive folding)

 

-are ectothermic

 
 
[q] birds (vertebrate)

[a] -covered in feathers (made of keratin)

 

-have internal fertilization (lay hard eggs)

 

-Breathe via lungs (with parabronchial tubes)

 

-are endothermic

 
[q] mammals (vertebrate)

[a] -covered in skin (with keratin hair follicles)

 

-internal fertilization (and mammary glands)

 

-breathe via lungs (with alveoli)

 

-Are endothermic

 
[q] simple dichotomous key to identify five vertebrate classes

[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)

 
[q] Clade
[a] Consists of a single common ancestor and all the descendants of that ancestor
 
[q] Cladogram
[a] Tree diagram where branch points show splitting of two new groups from a common ancestor
 
[q] how is biochemical evidence used to demonstrate evolutionary relationships

[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.

 
[q] advantages of mitochondrial DNA as a phylogenetic tool

[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

 
[q] Concept of the ‘molecular clock’ as a means of dating evolutionary relationships

[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)

 
[q] examples of when molecular evidence was used to reclassify existing schemes

[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

 
[q] Homologous structures

[a] -look different

 

-because of selective pressures

 

-organisms share common ancestry

 

-arise via divergent evolution

 

example: pentadactyl limb in vertebrates

 
[q] analogous structures

[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

 
[q] Label the parts of the digestive system

[a] -Salivary glands

 

-(O)esophagus

 

-Liver

 

-Stomach

 

-Gall bladder

 

-Pancreas

 

-Small intestine

 

-Large intestine

 
[q] Stomach

[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

 
[q] Pancreas

[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

 
[q] small intestine

[a] -A long, highly folded tube where usable food substances (nutrients) are absorbed

 

-Consists of three sections: duodenum, jejunum, and ileum

 
[q] large intestine

[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

 
[q] Liver

[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

 
[q] mechanical digestion
[a] The breakdown of food by physical actions (chewing, churning, segmentations, etc)
 
[q] Chemical digestion
[a] the breakdown of food by chemical agents (stomach acids, bile, enzymes)
 
[q] (salivary) amylase

[a] Source: salivary gland

Substrate: starch

Product: Maltose

Optimal pH: ~7

 
[q] pepsin (protease)

[a] Source: gastric pit (stomach)

substrate: proteins

Product: Short polypeptides

optimal pH: ~2

 
[q] (Pancreatic) lipase

[a] Source: pancreas

substrate: Triglycerides

product: glycerol + fatty acids

optimal pH: ~8

 
[q] Peristalsis

[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)

 
[q] Segmentation

[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

 
[q] label a tissue layer of the small intestine
[a] also know a top-down view
 
[q] Absorption
[a] The movement of fluids or dissolved substances across a membrane
 
[q] Assimilation
[a] The conversion of nutrients into fluid / solid parts of the organism
 
[q] How is the structure of the intestinal villus related to its role

[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

 
[q] active transport in the digestive system
[a] Glucose and amino acids are co-transported with Na+ ions
 
[q] Facilitated diffusion in the digestive system
[a] monosaccharides, vitamins, and some minerals are transported by channel proteins
 
[q] simple diffusion in the digestive system
[a] hydrophobic materials (ex: lipids) may diffuse freely across the epithelial membrane
 
[q] endocytosis in the digestive system
[a] dissolved materials are absorbed en masse by the process of pino cytosis (cell drinking)
 
[q] Digestion of starch (and subsequent transport of products)

[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

 
[q] Four main components of blood

[a] 1. Plasma

 

2. Red blood cells (erythrocytes)

 

3. White blood cells (leukocytes)

 

4. Platelets (thrombocytes)

 
[q] things the blood plasma transports

[a] -nutrients

 

-antibodies

 

-CO2

 

-hormones

 

-O2

 

-Urea

 

-Heat

 
[q] William Harvery’s findings on the circulation of blood

[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)

 
[q] Pulmonary circulation

[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

 
[q] Systematic circulation

[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

 
[q] Arteries

[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

 
[q] Capillaries

[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

 
[q] Veins

[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

 
[q] How is the structure of the arteries related to its function

[a] -have thick walls and narrow lumens because they transport blood at high pressure

 

-Have muscular/elastic walls to stretch with pulse flow

 
[q] How is the structure of the capillaries related to its function
[a] have walls that are a single cell thick because they exchange materials between blood and tissue
 
[q] How is the structure of the veins related to its function

[a] -Have thin walls with wide lumens and valves because they transport blood at low pressure

 

-Have valves to prevent backflow

 
[q] the role and location of valves in the circulation of blood

[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)

 
[q] which blood vessels supply the heart tissue with oxygen and nutrients
[a] coronary arteries
 
[q] label the parts of the heart
[a] memorize this baka
 
[q] the electrical events that trigger the contraction of the heart muscle fibers

[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

 
[q] Role of the medulla and epinephrine (adrenaline) in regulating heart beat

[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

 
[q] Systole and diastole

[a] -Systole described the period of heart contraction

 

-Diastole describes the period of heart relaxation

 
[q] pressure changes in the heart during the cardiac cycle

[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

 
[q] Occlusions to the coronary arteries

[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)

 
[q] Pathogens
[a] disease-causing agents (ex: microorganisms, viruses, and prions)
 
[q] Bactericidal
[a] kills the invading bacteria
 
[q] bacteriostatic
[a] suppresses its potential to reproduce
 
[q] How did florey and chain demonstrate the antibiotic properties of penicillin
[a] -The use of penicillin as a viable antibiotic was shown by florey and chain (1940)
 
[q] why are antibiotics effective against bacteria but not viruses

[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

 
[q] Five types of white blood cells

[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

 
[q] Functions and organization of the lymphatic system

[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

 
[q] role of surface barriers in the physical protection against infection

[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

 
[q] process of clotting

[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)

 
[q] causes and consequences of clotting in the coronary arteries

[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

 
[q] five non-specific defense mechanisms the body uses to combat infection

[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

 
[q] purpose of inflammation
[a] When tissue damage occurs, most cells and basophils release histamine which causes local vasodilation and increases capillary permeability to improve the recruitment of leukocytes to the region
 
[q] how do phagocytic leukocytes ingest and present pathogens in the blood and body tissue

[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

 
[q] two key properties of the adaptive immune system

[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

 
[q] antigen
[a] molecules that are capable of inducing an immune response
 
[q] antibody
[a] proteins produced by lymphocytes that recognize and neutralize specific antigens
 
[q] label an antibody
[a]
 
[q] alternative name for an antibody
[a] immunoglobulin
 
[q] antibody production

[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)

 
[q] three types of immune-system disorders

[a] -hypersensitivity disorders (allergies)

 

-autoimmune disorders (multiple sclerosis, lupus)

 

-Immunodeficiency disorders (HIV/AIDS)

 
[q] effects of HIV on the immune system

[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

 
[q] allergen
[a] environmental substance that triggers an immune response despite not being intrinsically harmful
 
[q] role of histamine in the allergic response

[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

 
[q] ventilation
[a] the exchange of air between atmosphere and lungs–achieved by the physical act of breathing
 
[q] gas exchange
[a] the exchange of O2 and CO2 between the alveoli and bloodstream (via diffusion)
 
[q] why is the ventilation system needed to maintain a concentration gradient within the alveoli

[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

 
[q] diagram the human lungs
[a] check bioninja topic 6.4 for the actual image
 
[q] purpose of the alveoli
[a] alveoli are the small air-filled sacs within lungs that greatly increase surface area and are responsible for GAS EXCHANGE
 
[q] Type I pneumocyte

[a] -mediate gas exchange with capillaries

 

-are long and thin (lower diffusion distance)

 

-compromise most of the alveolar surface

 
[q] Type II pneumocyte

[a] -Secrete pulmonary surfactant

 

-Reduces surface tension within alveoli (easier to inflate alveoli, preventing collapse)

 
[q] function of the pulmonary surfactant

[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

 
[q] How does Boyle’s Law relate to the mechanism of breathing

[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)

 
[q] Inhilation
[a] diaphragm and external intercostal muscles, increasing volume of thorax pressure in the lungs is decreases, so air flows in
 
[q] exhalation
[a] diaphragm relaxes and internal intercostals contract, decreasing thoracic volume. Pressure in the lungs is increased, so air flows out
 
[q] how do ventilation rates change with exercise

[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

 
[q] Spirometry

[a] measures the speed (flow) or amount (volume) of inhalation or exhalation

-This data can be recorded with a spirometer

 
[q] Causes of lung cancer

[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

 
[q] consequences of lung cancer

[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)

 
[q] causes of emphysema

[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

 
[q] consequences of emphysema
[a] common symptoms of emphysema include shortness of breath, phlegm, production, expansion of the ribcage, cyanosis and an increased susceptibility of chest infections
 
[q] role of sensory neurons
[a] sends signals from receptors to the central nervous system
 
[q] role of motor neurons
[a] sends signals from the central nervous system to effectors
 
[q] role of relay neurons
[a] sends signals within the central nervous system
 
[q] label a typical motor neuron
[a]
 
[q] resting potential

[a] -the charge difference across a membrane when the neuron is not firing (~70 mV)

 

-Maintained by the sodium-potassium pump

 
[q] action potential

[a] -the charge difference across a membrane when the neuron is firing (~30 mV)

 

-involves depolarization and repolarization

 
[q] depolarization

[a] -A sudden change in membrane potential–usually from a (relatively) negative to positive internal charge

 

-involves Na+ opening

 
[q] repolarization

[a] -The restoration of a membrane potential following depolarization (i.e. restoring a negative internal charge)

 

-involves K+ channels opening

 
[q] How does a nerve impulse pass along a non-myelinated neuron

[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

 
[q] What is the threshold potential represent
[a] the minimum level of depolarization required for an action potential to occur (all or nothing rule)
 
[q] how does the myelin sheath enable salutatory conduction

[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

 
[q] process of synaptic transmission
[a]
 
[q] how does synaptic transfer enable complex decision making in the CNS

[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

 
[q] the secretion and reabsorption of acetylcholine

[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

 
[q] how do neonicotinoid pesticides affect acetylcholine transmission

[a] Neonicotinoid pesticides bind irreversibly to acetylcholine receptors in insects

-AChE cannot break down neonicotinoids–this causes fatal overstimulation of receptors

 
[q] Homeostasis
[a] The maintenance of a constant interval environment within physiological tolerance limits
 
[q] role of negative feedback in homeostatic regulation

[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

 
[q] four conditions under homeostatic regulation

[a] 1. Body temp. (thermoregulation)

 

2. Blood glucose concentration

 

3. CO2 levels and blood pH

 

4. Water balance (osmoregulation)

 
[q] Horomone
[a] chemical messengers released from endocrine glands into the bloodstream to act on specific target cells
 
[q] role of thyroxin in body temp. regulation

[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

 
[q] melatonin in controlling circadian rhythms

[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)

 
[q] role of leptin in the control of appetite

[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

 
[q] role of insulin and glucagon in the regulation of blood sugar levels

[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

 
[q] Type I diabetes

[a] Onset: childhood (early onset)

effects: body doesn’t produce insulin

Cause: Beta cells destroyed (maybe autoimmune)

Treatment: insulin injection

 
[q] Type II diabetes

[a] onset: late onset (adulthood)

effects: body does not respond to inulin

Cause: insulin receptors down-regulated

Treatment: dietary management