IB MYP Biology Interaction with environment Study Notes

MYP PhysicsMYP MathsMYP ChemistryMYP Biology

IB MYP Biology- All Topics

 BIOLOGY INTRODUCTION

 

  • Biology is the study of living organisms and their interactions with the environment.
  •  Living things:
  • Respire
  •  Have a life cycle
  • Excrete
  • Move
  • Consume Nutritioro
  • Adapt to envirament
  • Sensitivity
  •  Have cells
  •  Grow
  • Reproduce

 Non-living things could do all of the above, except for grow and reproduce.

CELLS

  • Cells are the smallest units of life, but are capable of surviving in mediums free of life.
  • There are 2 main types of cells:
  • Prokaryotic (Before Nucleus): In unicellular organisms. They have no membrane-bound organelles.
  • Eukaryotic (True Nucleus): In multicellular bodies. They have complex organelles and are located in plants, animals

Functions of a cell include:

  •  Containing DNA
  • Sensitivity
  • Nutrition
  •  Making enzymes /proteins
  •  A cell contains organ elles, mini-organs that carry out these functions.

 How a cell compares to a factor:

  • Nucleus – Head office
  •  DNA – Manager
  •  Proteins – Product
  •  Smooth Endoplasmic Reticulum + Ribosomes – Machinery
  • Cytoplasm – Free space
  • Vacuole-Storage Room
  •  Cell membrane – Guards
  •  Mitochondria – Power House
  • The cell membrane is a sheet like protective surface. It is selectively permeable, and lets only some particles pass through. It is made of a phospho-lipid bilayer.
  •  Ribosomes are small globular structures that produce proteins. Ribosomes are made in the Nucleolus. There are two types of Ribosome es free and membrane-bound ribosomes. Free ribosomes roam around freely in the cytoplasm. They synthesize proteins for the use of the cell, while the other type, membrane – bound (attached to Rough Endoplasmic Reticulum) synthesize them for external use.
  •  The Nucleus is the Head office of the cell. It contains the DNA. The Nucleus have 5 components:

  • The Nucleolus makes Ribosomes. The Chromatin contains DNA, and it condenses to form Chromosomes
  • The Cytoplasm is the jelly-like substance inside a cell that counts as free space.
  • The Rough Endoplasmic Reticulum (RER) is right outside the -Nucleus. It is a flattened structure, and is joint to the Nucleus Envelope. It synthesizes and modifies proteins (polypeptides) – It has ribosomes attached to it, giving it a “rough” appearance.
  • The Smooth Endoplasmic Reticulum (SER) synthesizes lipids and removes harmful! substances. This process is known as detoxification. The SER also creates vesicles.
  • The Golgi Apparatus (also called Golgi Body) is a flattened disk-like structure. It has the same membrane as the Cell Membrane. It processes and packages proteins in vesicles. Vesicles are thus mo diffed with in. Then, they (the vesides) merge with the Cell Membrane. The flattened shape of the Golgi Body gives a higher surface Area: volume Ratio.
  • Mitochondria is the “power house of the cell. They carry out cellular Respiration. They have their own ONA. Th of create ATP (Adenine Triphosphate), which helps create and send energy whee ATP is a currency. They have 2 membranes, so enzymes are attached to them?
  • The chloroplast is the other organelle with a double membrane. It contains a pigment called Chlorophyll, which gives the chloroplast its green colour and helps in photosynthesis (which is why chloroplasts are only present in plants and algae).
  • Vacuoles are large fluid filled spaces enclosed by membranes. Plants have any large, central vacuole, while animals have several temporary and small vacuoles. Their membranes are called tonoplasts. It is permeable to water. vacuoles contain salt and glucose.
  • Centrioles are small, round structures that help in coll division. They are only present in animal cells. They  appear in pairs. In any cell, there is only one pair of centrioles. They have a copy of the DNA and are protenin nature.
  • The Cell Wall is an external layer only present in planks. It is made up of cellulose. It has a rigid structure and is completely permeable. It provides support and prevents bursting. It can withstand water pressure.
  • Lysosomes are Digestive Plants for proteins, fats and carbs. They transport undigested material to the cell membrane for its removal. The cell can break down if the Lysosome explodes.
  •  Differences between plant and animal cells:

Organelles figures:

(1). CELL MEMBRANE (Phospho -Lipid Bilayer)

(2) CELL WALL

(3) NUCLEUS

(4) ENDOPLASMIC RETICULUM

(5) RIBOSOMES

(6) MITOCHONDRIA

(7)GOLGI APPARATUS

(8) LYSOSOMES

(a) CHLOROPLASTS

  •  Some cells are specialized. They are modified and have particular structures and functions. They are formed through a process called “Cell Differentiation”.
  • Classic examples of specialized cells are Red Blood cells (RBCS). They transport oxygen throughout the body and remove Carbon Dioxide. It needs storage, which is why they have no nucleus. It needs to store haemoglobin (a metalloprotein). They are created in the bone marrow. At the time of creation, they have a nucleus, but they remove it for Increased storage. They have a biconcave shape to increase the surface Area to volume patio.
  •  Stem cells are cells that have not yet differentiated. They are raw cells, and can order for the growth of the Liver, Heat, Kidney etc. Although the Heart, Liver etc. are organs, stem cell’s can order for their growth because:

(1) CELLS

(2) TISSUES

(3) ORGANS

(4)  ORGAN SYSTEMS

(5)  ORGANISMS

  •  Histology is the study of tissues. There are 4 types of tissues:

(1) Ephithelial-Coversurfaces
(2) connective -support, Transport, Storage
(3) Muscles – contract
(4) Nevral-Cary Signals

  • Antagonistic muscles are pairs of muscles working in opposite directions.

TRANSPORT

  • There are 2 types of transport:

  • Diffusion is the movement of particles from an area of higher concentration to lower concentration. Active transport is the opposite, but it requires energy.
  • Osmos is is the movement of water partic les from an area of higher water potential to lower water potential across a partially permeable membrane.
  •  There ore 3 types of solutions:
  •  Hypotonic: Solvent > Solute
  •  Isotonic: Solvent = Solute
  • Hypertonic: Solvent< Solute
  •  Brown mean motion is the random type of motion of gas particles.
  •  Temperature affects particle movement. More temperature causes more kinetic energy, resulting in so. Mass affects particle movement. More mass causes more inertia. So a smaller mass allows formore speed of the particles. This goes for all types of transport.
  •  In Osmosis, equilibrium is equal concentration on both sides of a membrane. Even then, the particles keep moving, but the overall rate of diffusion does not change much

 How Osmosis works:

  •  Water molecules are polar too. However, they are so small that they can diffuse across a membrane,
  • when a cell is placed in water, the cell will give out water, because the concentration outside the cell is greater. Hence, the cell shrinks. This process is called plasmolysis. In hypotonic solutions, the cell will take in water, causing it to burst. This process is called Lysis. plant cells plasmolyse, but do not burst. This is because of its cell wall. The pressure on the Cell wall (given by the expanding cell Membrane) is called turgor pressure – the phenomenon is called turgidity. the plant becomes turgid.

  • Cells are deliberately very small. If they were bigger, nutrients would not enter the cell fast enough, and heat and waste would not be released so quickly. A smaller cell size increases its “Surface Area :Volume Ratio”
  • Here, the Surface Area has to do with the amount of nutrients/resources that can enter the cell at one time.
  • The volume has to do with the amount of nutrients needed to run the cell.
  • However, the SA:V Ratio should not be too high, else the excretion of waste becomes harder. If this happens, cells typically divide.

  •  Here, the shape of cells is taken as cubes for ease.
  • Size 1 is ideal, while 6 is the maximum, after which a cell starts showing inefficiency

ORGAN SYSTEMS

  • A group of organs working together is called an org an system. There are 11 organ systems in the human body:
  • Digestive
  •  Excretory
  •  Circulatory
  •  Respiratory
  • Nervous
  • Immune
  • Reproductive
  •  Endocrine
  •  Etc.

Before we get to digestive system, it is important to understand 1 what food we should consume, all the nutrients etc. Nutrients are substances that provide you energy. In a balanced diet, one needS B BALANCE, VARIE’TY and MODERATION.

 Categories of food.

Macronutrients (high quanties) (carbohydrates) (Proteins)( Fibers)( water) (Fats)

Micro nutrients (small quantities) (vitamins minerals)

  •  Water is a Universal Solvent. It carries Nutrients and Waste Regulates body Temperature, Dissolves Nutrients and Lubricates joints. Up to $70 \%$ of the human body is water.
  •  Fiber is not really a nutrient. It just helps in digestion (which is why faeces is often the quick result of consuming an apple). Fibereduces the chance of obesity, and is not broken down during digestion.

 Carbohydrates are the body’s main source of energy. There are different types of carbs:

Carbohydrates

  • Polysaccharides have vitamins, minerals and fiber.
  • Proteins, or Polypeptides, provide energy on the last resort. They help repair body His sues. They are made up of ch epical compounds called amino acids. There are 20 types of amino acids (building blocks of proteins) 11 of these can be produced by the human body a of these come from the food we consume. Complete proteins provide these a essential nutrients.
  • Fats/Lipids have the most amount of storage. They are hydrocarbons. Its functions are:
  • Providing substances
  • Providing energy
  • Enhancing taste/texture of food.

Fats

  • Cholesterol is a fat-like substance part of every cell of the body. It helps the body make necessary cells and aids in digestion. It is found in animal meat and created in the human body.
  •  Vitamins are nutrients that do not provide energy. They help regulate chemical processes.

Two types:

(1) Water Soluble C, B (large quantities)

(2) Fat Soluble $A D, E, K$ (small quantities)

  •  Minerals are inorganic micro-nutrient’s that do not provide energy.

Vitamins.

 Vitamin A (Fat Soluble):

  • Sources: Green vegetables, liver
  •  Deficient: Nyctalopia
  •  Function 1: Keeps skin thar healthy
  • Function 2: Aids in night vision

 vitamin B-Complex (water Soluble):

  • Sources: Peas, wheat
  •  Deficiency -Vitamin B-12 Deficiency
  • Function 1:Utilises body energy
  • Function 2: Helps brain / nerves be strong

 vitamin C (water Soluble):

  •  Sources: Citrus fruits, Kiwi
  •  Deficiency: Scurvy
  • Function 1. Heal Wounds
  • Function 2: Fight Infections

vitamin D (Fat Soluble):

  •  Sources Yolk, Salmon
  •  Deficiency: Rickets
  •  Function 1: Utilise cal cium/p hos phons
  • Function 2: Build strong bones/teerh

 vitamin E(fat Soluble):

  • Sourcesivegetable oils, Nuts
  •  Deficiency: Abetallipoproteinemia
  • Function 1: Antioxidant
  • Function z: Enzymatic Regulation

vitamin K (Fat Soluble):

  • Sources : Kale, Spinach
  •  Deficiency. vitamin K Deficiency
  • Function 1: Regulation of blood clotting
  • Function 2 : Response to injury

Minerals:

  • Calcium:
  •  Sources: Milk, Cheese
  • Deficiency: Osteoporosis
  • Function 1: Helps heart be strong
  • Function 2: Helps bones be strong

P0tassium:

  •  Sources Squash, Potatoes Deficiency: Hypokalemia
  • funtion 1 Balance of food/etectolyte
  • Function 2 function of living cells.

Sodium:

  •  Sources: Celery, Beetroot
  • Deficiency: Hyp ponatrema
  • Function 1: Balance of fluids
  •  Function 2: Transmit nerve signals

Magnesiums

  •  Sores Spinach, Almonds
  • Deficiency: Magnesium Deficiency
  • Function 1: For biochernical reactions
  •  Function 2: Heartbeat Steadiness

Phosphorus:

  • Sources: Milk, Beans
  • Deficiency: Rickets
  • Function I: Growth of tissues
  •  Function 2 : Bone structure/strengh

Chloride:

  •  Sources. Table Salt, Tomatoes
  •  Deficiency :Fluid loss (Dehydration, vomitetr)
  • Function 1: Osmotic pressure offluids
  • Function 2: Aad-base balance

Iron:

  •  Sources: Liver, Fish
  • Deficiency: Anemia
  • Function 1: Making Hemoglobin
  •  Function 2: Use of Oxygen

 Manganese:

  •  Sources: Beans, Seeds.
  •  Deficiency: Manganese Deficiency
  • Function 1: Fat/Carbs Metabolism
  • Function 2: Blood Sugar Regulation

Iodine:

  • Sources: Cranbernes, Kelp
  • Deficiency: Goiter
  • Function 1: Thy rood functioning
  • Function 2 : Conversion of food beregy

Chromium:

  • Sources: Bre ad, Brocolis
  • Deficiency: Diabetes
  •  Function 1: Fatkcarbs Metabolism
  • function 2: Insulin action

 Fluoride:

  • Sources: Walnuts, Cocoa Powder
  • Deficiency: Tooth Decay
  •  Function 2: Mineralization of teeth
  •  Function 2 : Mineralization of bones

 Copper:

  •  Sources: Potatoes, offal
  • Deficiency: Wilson Disease
  • Function 1: Proper Growth
  • Function 2: Maintenance of organs

Selenium:

  • Sources: Sardines, Beet
  • Deficieng: Hypothyroidism
  •  Function 1: Making antioxidantenzmes
  • Function 2: Preventing cell damage

 Mglgbdenum:

  • Sources: Beans, Lentils
  • Deficiency: Molybdenum deficiency
  • Fundion 1: Catalyst for enzymes
  •  Function 2: Catalyze amino acids nh who

Zinc:

  •  Sources: Oysters, Red meat
  •  Deficiency: Diarrhea
  •  Function 1: For immune system b work
  •  Function 2: Senses of smell and tate

 Having looked at the types of food, the digestive system is not hard to undestand.

  • The digestive system has to do with the process of consumption and breaking down of food and nutrition in our bodies. Digestion is both chemical and mechanical. Its phases include:
  • Ingestion (swallowing 3 food)
  • Movement
  • Mechanicalchemical Digestion
  •  Absorption (nutrients moving into cells)
  •  Elimination (excretion – continued in excretory system).
  •  The GI tract (Gastrointestinal Tract) is the main pathway in the digestive system. It comprises of:
  •  Mouth
  • Teeth
  • Epiglottis (flap-like structure that prevent food from going down the windpipe).
  • Esophagus
  • stomach
  • Intestines
  • Small
  • Large
  •  Rectum
  • The Esophagus is a $10^{\text {” long }}$ tube that secretes mucus, moves food from the throat using wave-like motion (peristalsis):

                      (wave-like motion due to contraction of tube muscles)

  • In the mouth, teeth mechanically break down food into smaller pieces. The tongue mixes saliver with the food. The amylase in the saliva helps break down starch. The epiglottis prevents food from going down the windpipe, after that, it goes to the stomach.
  • The stomach is a J-shaped – muscular sac that has digestive juices (such as Hydrochloric Avid) with enzymes that help break down frotens/Polypeptides. The stomach has a pH of 1.5 . The enzymes that break down proteins a re called proteases. the food stays in the stomach for 4 hours. Fast food stays longer. The pyloric sphincter covers the mouth of the stomach, and the churning food does not come out.
  •  In the mouth, teeth mechanically break down food into smaller pieces. The tongue mixes saliva with the food. The amylase in the saliva helps break down starch. The epiglottis prevents food from going down the windpipe after that, it goes to the stomach.
  • The stomach is a J-shaped muscular sac that has digestive juices (such as Hydrochloric Avid) with enzymes that help break down Proteins/Polypeptides. The stomach has a pH of 1.5 . The enzymes that break down proteins a re called proteases. the food stays in the stomach for 4 hours. Fast food stays longer. The pyloric sphincter covers the mouth of the stomach, and the churning food does not come out.
  • After 4 hours in the stomach, the food (which most of has been digested anyway), the food moves to the small intestine. This is the longest single organ of the body. The food is digested using pancreatic amylase. It has small, finger like projections (villi), which themselves have smaller versions of themselves (microvili:). They aid in increasing the surface Area to volume Ratio. Within the small intestine, lacteal (lymphatic vessels) absorb fats. The small intestine absorbs:
    $.80 \%$ ingested water
  •  Carbohydrates
  •  Proteins Polypeptides
  •  Fats/Lipids
  •  Vitams
  • Minerals
  • The large intestine accepts what the small does not. The bacteria in the large intestine foment carbohydrates and break down proteins. The large intestine continues to the rectum, where food is excreted in the form of faeces.
  •  Accessory organs are organs which play indirect roles in an organ system.
  • The Liver affects digestion in the following wags.
  • Emulsifies fats. The liver breaks down the fats into many smaller pieces. This increased surface area allows for sped up digestion.
  • Filters toxins, that leave the body as urea (partides that make urine yellow)
  • secretes bile (made of worm out Red Blood Cells) that helps in. digestion of fats.
  • The Gall Bladder stores this bile, and releases it into the small intestine when necessary.
  •  Too many fatty diets can cause gallstones.
  •  The pancreas produces digestive enzymes (biological catalysts) that help break down proteins and lipids. It also produces insulin, which regulates blood sugar levels.
  • The Digestive System is closely tied with the excretory System. This has to do with releasing waste, from the body.

  • The Excretory System removes harmful and waste products from the body. While a major component of this system is the Urinary system, the excretory system is not solely based on it, and includes:
  • Lungs
  •  Liver
  • Sweat G lands
  •  Kidneys
  • Small Intestine
  •  Large intestine
  • Etc.

  •  The lungs excrete carbon dioxide and water through the respiratory process. Alveoli in the lungs diffuse air and $\mathrm{CO}_2$. When we exhale, we let out $\mathrm{CO}_2$. (continued in respiratory system)
  • The Liver detoxifies blood and converts harmful substances into urea. This is excreted along with urine
    The skin uses sweat glands to help cool down body in the form of sweat/perspiration. It includes:
    $.99 \% \mathrm{H}_2 \mathrm{O}$
  •  Salts
  • Urea
  • Heat

 

  • The kidneys are the most important part of the excretory system. They are fist-sized and beanshaped. They have two million nephrons in total that filter the blood of toxins. At the end of each neuron is a Glomerulus (a clump of capillaries) that diffuse wastes out of the body. Homeostasis (maintorre of on internal environment) must be maintained, else problems like Bladder/kidney infections, Kidney stones, Kidney Disease, out etc. After the kidney, her parts of the urinary system come in to play.
  • The ureters are narrow tubes which connect the kidneys to the bladder, a muscular sac that urine. Through the letha ( atube leading from the rime is excreted out body.
  • Large Intestines/small Intestines play roles in the expulsion of faeces. The small intestine leads to the large intestine, which leads to the rectum and then the anus, from where food is expelled in the form of faeces.
  • The circulatory system is an organ system that is a fluidfiled network of vessels throw which materials. move between the environment of an organism.

 Types of circulatory systems: 

  • Open: Insects, *nthropods – Closed:
  • Fish and small mammals (single)
  • Humans (double)
  • The circulatory system transports Oxygen and Glucose into cells, and removes $\mathrm{CO}_2$ and Urea:

 Components:

  • Heart
  • Blood vessels
  •  Arteries (tubes carrying oxygenated blood away from the heart)
  • veins (tubes carrying deoxygenated blood back to the heart.
  • Capillaries (mesh of single cell thick tubes that are the actual site of diffusion).

Blood

  • Red Blood Cells (transport)
  • White Blood cells (immune Defense)
  • Platelets (clotting)
  • Plasma (medium for transport)

  •  veins have values so that the blood coming back from various parts of the body does not flow back. Arteries do not have valves because the blood flow rate from the heart is already very high.
  •  Important vessels:
  •  Pulmonary Artery (Heart $\rightarrow$ Lungs)
  •  This is deoxygented blood (only exception for artery)
  •  Pulmonary vein (ungs $\rightarrow$ Heart)
  •  This is oxygenated blood (only exception for vein)
  •  Aortic arch and trunk (main arteries from heart)
  • Common carotid artery (blood to brain
  • Renal venlartery – connect to kidneys
  • Mesentric vein -Connect to intestine
  • Hepatic Portal vein -Blood from GI tract to liver

  • Acesony organs
  • Lungs: $\mathrm{O}_2$ taken in, $\mathrm{CO}_2$ releaset
  • kidneys: Whee waste is removed
  • small Intestine: Digestion
  • Large Intsotie: Absorbing water
  •  Blood pressure is the amount of force exerted by the blood on the arteries. There are two types of blood pressure:
  • Systolic (ventricles contraction) – Nornoal: $110-140$
  •  Diastolic (expansion of ventricles) – Normal. $70: 90$
  • The circulatory system is tied to the respiratory system. There are 3 types of respiration:
  • Cellular: Aerobic breakdown of of glucose in mitochondria to make ATP.
  • Respiratory system: Organs in animals that exchange gasses with the environment.
  • Respiration: The everyday word used interchangably with breathing
  • Respiratory systems allow animals to move oxygen into body tissues and remove $\mathrm{CO}_2$.
  •  Structures for res piration:
  •  Aquatic: Gills
  • Insects: Spiracles
  •  Vertebrates: Lungs

Type of exchange: Counter current

  • Equilibrium is not reached, So more $\mathrm{CO}_2$ can be excreted.
  •  Components:
  • Trachea
  •  Bronchi
  • Bronchioles
  • Alveoli
  • Diaphragm
  •  Lungs
  • Nasal and Buccal Cavity -where air enters the body via the nose and mouth.
  • Move to pharynx and Larynx (throat cavity and voice box respectively) through epiglottis (fiap-like structure that stops food from going down the respiratory tract.
  •  Trachea is a large tube reinforced by rings of cartilage. Mucus in the trachea constantly traps inhaled particles. Cilia, small, hair-like structures inside the track ea, sweep moas and inhaled particles to the pharynx – it’s what we spit on.
  • Trachea are lined with smaller tubes called bronchi – these shuttle air to and from the lungs They are lined with bronchioles which ensure air is provided to alvedi (moist, thin-walled pockets that are the site of gas exchange. An oily surfactant keeps them from sticking together.
  • Air comes in through the Diaphragm. These are muscles in rib cages. When they and intercostal muscles contract and expand, air is inhaled and exhaled. Gas exchange of $\mathrm{CO}_2$ and $\mathrm{O}_2$ take place of both longs and body cells.
  •  Respiratory problems:
  • Smoking – Increased tar, nicotine and $\mathrm{CO}_2$ inside, cause cancer and em physema (avedid dry up)
  •  Bronchitis -swelling of bro nodi due to infection
  • Asthma – Bronchial swelling and blockage.

 

  • Steps:
  • Contraction of Diaphragm
  • Air inhaled through nose/mouth
  •  Trachea cilia clean air
  •  Diffusion takes place.
  • Diaphragm expands
  •  Air exhaled
  •  The nervous system has to do with the transferral of signals to the brain and its functions. The neuron cell is what does most of this.

  • Functions:
  •  Dendrites receive signals from other cells.
  •  Cell body integrates signals.
  • Axon transmits action potential
  • Mydin sheath speeds up transmission
  • Synaptic terminals transmit signals to elsewhere.
  • Nevers do not usually directly – they have gaps called synaptic terminals that transmit the signal.
  • Intensity of stimulus = frequency of action potentials.

  • Neural pathways consist of:
  •  Sensory Neurons
  •  Association Neurons
  • Motor neutrons
  • Effectors

The simplest neural pathway is the reflex arc. They carry out the reflex in association with the spine before the brain wen knows about it.

  • Sections of mind:
  • Hindbrain: Basic functions
  •  Pons: Sleep
  •  Cerebellum. Movement
  • Medulla: Autonomic functions
  • Midbrain: Filters sensory input, allowing concentration
  • Forebrain: Stores memories and complex though ts.
  •  Cortex:Highe thought
  •  Thalamus: (Cane) sensory info
  •  Limbic system: Basicfeelng
  •  Human senses:
  •  Thermoreception: Changes in temperature felt
  • Mechonoreception: Hearing
  •  Photoreception : Sight
  • Chemoreception: Taste,smell, seise of pain.

Synthesia is the development of cross-sensony perceptions.

Spinal cord is protected by vertebrae

PNS extend outside vertebrae

 The immune system has to do with fighting bacteria, viruses and other microorganisms from harming the human body.

  • Functions
  • Communication
  •  Killing enemies
  •  Standby mode
  • Fighting worms
  •  Causing inflammation
  •  Activating other cells
  •  Producing antibodies
  • Killing infected cells
  • Making strategic decisions
  • Remembering enemies
  • Marking disabling enemies

 Cells involved/Protein forces:

$\left.\begin{array}{l}\text { – Macrophages } \\ \text { – Eosinophils } \\ \text { – Neutrophils }\end{array}\right\} \begin{aligned} & \text { white } \\ & \text { Blood } \\ & \text { cells }\end{aligned}$

  • Natural killer cells
  •  Complements
  • Mast Cells
  • Monocytes
  • Follicvlar Dendritic Cells
  •  Dendritic cells
  •  Memory helper T cell
  • Virgin helper $T$ cells
  • Helper T cells
  •  Memory Helper T Stem cells
  • Virgin killer T cells
  • Antibodies
  • killer T cells
  • Memory killer T cells
  •  Virgin B cells
  •  B cells
  •  Memory B stan cells
  • Memory killer T stem cells

How the immune system works:

  • Through a wound (such as by a nail), bacteria, viruses etc. enter the body, the skin is breached. They start using the body’s resources, and double in number about every 20 minutes.
  • Macrophages intervene. Mostly, they alone can supress an attack. They swallow intrudes whole and trap them inside membranes where enzymes break them down. The macrophages order blood vessels to release fluid, making fighting easier. This causes inflammation. It they fight for too long, they use messenger proteins that call in the next backup Neutrophils.
  • The neutrophils release toxins and create barres that try to stop the bacteria. They fight so furiously that they cen. fill heathy cells. They commit suicide after 5 days to prevent too much damage. If they canst suppress the attack, Dendritic cells take action.
  • The dendritic cells take samples of the intruders and travel to the lymph node in about a day, where helper and killer $T$ cells are waiting to be activated.
  • The Helper $T$ cells are born through a difficult manufacturing process where only $\frac{1}{4}$ survive, The dendritic cell look’s for T cells that have antibodies that fit right into the antigens.
  • The Helper I cells multiply, some becoming the Memory Helper Dells. They stay in the Lymph Node, and make you immune to the disease by remembering how to counter it in the future. The rest of the $T$ cells trave) to the center of the Lymph Node that activates the (virgin) $B$ cells – extremely powerful weapons.
  • The B cells fight so hard that they die of exhaustion, but the Helper I cells provide resources and stop them from doing 50 . The B cells produces millions of weapons-antibodies. The B cells die once the infection is over, to stop the body from loosing too much energy, The antibodies (proteins) attack in billions to the bacteria, killing/stunning them. Macro phages, are especially useful for killing these stunned bacteria. The cells commit suicide so as not to waste bod resources. However, the memory cells (T arid B) alive and remember to counter the same y again-buttery

  • knowing how the immune system works, understanding vaccination is not that hard.
  • A vaccine is a medication or a disease that immunizes patient against disease.
  •  Types of immunization:
  • Passive:
  •  Natural Passed from
  • mother to child before
  • birth.
  • Artificial : Prepared antibodies injected using serum
  •  Active:
  • Natural: Naturally acquired immunity though activation of antibodies 
  • Artificial. Achieved by vaccines/toxoids
  • Types of vaccines:
  • Live-attentuated: Strains of weakened pathogens
  •  Iteterologous: Sub-group of Live-att enuated vaccines of pathogenic organisms in animals (not humans) – Inactive/Killed: Bacteria viruses are killed for this
  • Sub-unit: Are made up of only antigens (the part of the pathogen responsible tor immune response).
  •  Toxoid: Used when a bacterial toxin is the main cause of illness.
  • Peptide: Subunit vaccine prepared by chemical synthesis of short immunogenic peptides.
  •  The first ever vaccine was created by Edward Jenner for smallpox using cowpox.
  • The endocrine system has to with the release of hormones the body. Hormones are emical substances that help here homeostasis (a genera) of the maintenance an internal body environment.
  • Homeostasis levels:
  •  Water Balance:
    $.90 \%$ of blood volume
  •  $\mathrm{CO}_2$ concentration.
    $.10-13 \mathrm{KPa}$
  • Body temperature:
    . $36^{\circ} \mathrm{C}-38^{\circ} \mathrm{C}$
  • Blood Glucose Concentration
    $.80 \mathrm{mg} \mathrm{dl}^{-1}$ – $110 \mathrm{mgdl^{-1 }}$
  • Blood PA:
    . PH $7.35-7.45$
  • Examples of body hormones:
  • Insulin (secreted by beta cells of the pancreas causes the glucose to turn into glycogen. This decreases blood sugar levels.
  • Glucagon (secrete) by alpha cells of the pancreas) does the opposite. It convert glycogen to glucose.
  • Thyroxin is secret et by the thyroid gland to regulate the metabolic rate and help control body temperature.
  • Leptin is secreted by cells In the adipose tissue that controls desire for food/appetite.
  • Testosterone causes sperm production and development male secondary sexual characteristics in puberty.
  • O estrogen and progesterone during female secondary ixia) characteristics.
  •  Feedback loops:
  • Negative: Feedback causes hormones to maintain homeostasis by ordering to increase/dercase levels accordingly.
  •  Positive: Increased rise

ECOLOGY

  • Arrangement Levels:
  • Organisms
  •  Species
  • Populations
  • Communities
  •  Ecosystems
  • Biomes
  • Biospheres:
  • Atmosphere (Air)
  • lithosphere (Land)
  • Hydrosphere (water)
  • Ecology is the study of relationships between living organisms and other organisms and the environment.
  • based on feeding patterns, there are 2 types of organisms: – Autotrophs Produce their own food – Heterotrophs : consume others

                           

  • The highest level of predators are always fewer in number – it is nature’s way of protecting and ensuring balance.
  • Energy in a food chain goes waste and cannot be recycled. only $10 \%$ of energy is passed on to a consumer:

                    

  • There are 2 types of factors that affect an ecosystem: – Abiotic (non-living)
  • Light
  • Climate etc.
  • Temperature
  • Biotic (living)
  • Organic mátter
  •  Consumers etc.
  •  Producers
  •  Factors controlling an ecosystem: – Nutrients: (closed system)
  •  Carbon
  • Nitrogen
  •  Phosphorus
  •  Energy (open system)
  •  Interactions between species
  •  The cycling of these nutrients is critical for rife on earth:
  • Al proteins a nd ar have Nitrogen
  •  All cells have ATP (phosphates)
  •  Carbon gives energy

       

                               IT IS A CLOSED Cycle

  • Plants carry out photosynthesis to create their own food. How Photosynthesis works:

INSIDE OF LEAF

1. $\mathrm{CO}_2$ moves in through the stomata opening of the leaf.
2. Photosynthesis uses $\mathrm{CO}_2$ Keeping the concentration of $\mathrm{CO}_2$ low inside leaf.
$3 \cdot \mathrm{CO}_2$ from outside the left diffuses down the concentration gradient
4. Oxygen is released.

 Formula for Photosynthesis:

$6 \mathrm{CO}_2+6 \mathrm{H}_2 \mathrm{O} \stackrel{\text { sunlight }}{\longrightarrow}$ $\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6+6 \mathrm{O}_2$

  • Factors affecting Photosynthesis:
  • $\mathrm{CO}_2$ concentration
  • Light intensity
  • Temperature
  • $\mathrm{PH}$

  • Rate of photosynthesis is measured by.

$
\text { Rate }=\frac{\text { change }}{\text { time }}
$

  • An enzyme is a globular protein which acts as catalysts in biochemical reactions.
  •  A substrate is the reactor’ in a biochemical reaction. In the case of photosynhises, $\mathrm{CO}_2$ is the substrate.
  •  How an enzyme works:
  • But, an enzyme can also produce products that sometimes do not match its shape. This is called the induced fit model.

Enzyme revert’s to shape, releases products.

                                                     There are several different types of plants

                               

                        

  •  There are 2 main vascular tissues – xylem and Phloem.
  • xylem transports water, Phloem transports food.
  • PHloem $=$ Food
  •  Dicots cross-section

                           

  • Transpiration is the loss of water from leaves and Stems of plants. Xylem transports the water. This process helps cool down the plant and the atmosphere. Transpiration flow is controlled by the rate of water loss through the stomata.

Tropism is a plant’s responses to directional externalstimuli. They can positive (towards limulus) or negative (away rom stimulus)? Plant growth regulated by hormones led auxins.

  • $\mathrm{CO}_2$ uptake $\propto$ Water uptalk
  •  The hormone absisic acid is produced to close stomata.
  •  Factors affecting rates of transpiration:

   

  • Plant reproduction:
  •  Sexual
  •  Self Pollinated
  • Cross Pollinate ed
  •  Asexual
  • Budding
  •  Vegetative Propagation
  • Parts of a flower:

  • Climate change has been prevalent ever since the discovery of coal, natural gas and other fossil fuels.
  • Climate IS NOT weather. Climate is the average weather at a given point in a year, over a long period of time, typically 30 years.
  •  Climate change is mostly a result of increasing greenhouse gasses (such as $\mathrm{CO}_2$, Methane, water Vapour etc.)
  •  The climate has increased dramatically in the past 100 years Examples:
  •  Tornadoes
  • Dust storms
  • Hail
  • Lightning
  • Etc

GENES AND DNA

  • DNA stands for Deoryribonuctio acid. It is a macromolecule that contains the genetic code. It contains the code that determines the shape and structure of living organisms.

          

DNA is made up of nucleotides. The structure backbone is made of phosphates and sugars. The 4 bases determine the genetic code.

  •  The order of the 4 bases determines the genetic code.
  • A gene is a section of the DNA that codes for a specific trait, such as eye colour, skin colour etc.
  •  RNA, or Ribonudeic Acid is a polymeric molecule essential in various biological roles, induing coding, decoding.

  •  Alleles are alternative versions of a gene. They come from either parent.
  • The DNA in cells is not stored as one long strand, but is divided and coiled into certain indwidual lengths called Chromosomes. Humans have 23 pairs of chromosomes – one from each parent.
  •  If the order of the bases is changed, even to the slightest extent, a mutation takes place. This is caused by base x change etc. or by mutagens. mutation taking place in a mete (sperm or egg) can be ed on to the rext generation. areas mutations in the body be harmless or cause cases like cancer. Examples include x-rays, cigarettes ete.
  • There are 3 main types of mutations: Insertion, Deletion and Substitution.

Side effects and examples of dangerous mutations:

Insertion

  •  Hunington’s Disease
  •  Fragile X syndrome

 Deletion

  • 22 . 21.2 deletion syndrome

 Substitution

  •  Sickle cell Anemia

Down syndrome is a genetic mutation in which a third of chromosome 21 appers. associated with physical\ growth delays.

  • Heredity refers to the transmission of physical characteristics from an organism to its offspring. Physical characteristics of the offspring are created by the mixing of physical characteristics of the parents, or sometimes further ancestors. The inheritance of these traits can be represented by a Punnet square. The concept of heredity was introduced by fregor mendel, who worked with peas.

 Punnet square

Dominant traits arc represented by capital letters, while recessive traits are shown by lower case letters

A pedigree chart can also be used:

Rules:

  • Females are circles
  • Males are squares
  • Couples connected by a Vertical line.
  • oldest to youngest are from left-most to right-most respectively
  • Full-shaded shows person who shows trait
  • Half-shaded represents trait carrier
  • Blank has no trait

 There ore 2 types of alleles: Dominant and Recessive. Dominant alleles are those which require only one copy to be shown, while recessive need both. They (recessive) need to be homozygous (same (etter = same allele )

  •  This was because the green trait was hidden, with two possible alleles of (recessive) green peas. In the $2^{\text {nd }}$ generation, green was in the genotype (allele), but yellow was bo ot h in the gen otype and the phenotype (physical trait).
  • This process is called Monohybrid inheritance. This con be defined as creating an offspring of one type in two contrasting genes.
  •  Someone coding for the same allele (like YY) is homozygous, while someone coding for different alleles is heterozygous.
  • There are 3 types of dominance, complete, $\mathrm{CO}_{-}$, and Incomplete types of Dominance.

 There are 2 types of cell division :.Mitosis (Asexual) and Meiosis (Sexual).

  •  Mitosis is a type of cell division (asexually) that results in two daughter cells being produced from a single parent cell. The daughter cells ave the same number and kind of chromosomes as the ent nuclers. Mitosis occurs most of our body cells matic cells). The exact cop $y$ the DNA is made. The newly DNA is made. The newly rematids. They are joined by centromeres.
  • When the number of cells increases, the organism begins to grow.

There are 6 phases of Mitosis:

 

REMEMBER ORDER BY: IPMATC

(1) Interphase

The centromere opens. Two identical copies of the chromosomes are made. These are called chromatids. The organenes of the cell are also doplicated during this time. The cell also increases in size at this time. The majority of the cell’s life is spent during this thine.

(2) Prophase

The DNA has aread $y$ been duplicated by now. The chromosomes get condensed, and the  nucleolus is remored.

(3) Metaphase

The Nuclear Membrane breaks off. The spindle fibers attach to the chromosomes. The chromosomes line up all the equator of the cell.

(4) Anaphase

(pg) The spindle fibers shorter,  centromere disappears pulled apart. The cell is ready for cell replication now

(5) Telophase

Nuclear Membrane respears. In oval shape, for now. Spindle fibers brent apart.

(6) Cytokinesis

The cell splits into two daughter cells – same number of chromosomes.

CYCLE REPEATS

  • Meiosis goes through similar phases. Meiosis only takes place in germ cells gametes (sperm and egg cells).

  •  However, in Meiosis, the daughter cells are not identical. This is because in Prophase 1, the two chromosomes “cross over’, and the genes are mixed.

Problems in Mitosis and Meiosis:

  • In Mitosis, if the cell does not halve equally, the cell could have 45 or 47 chromosomes.
  • In Meiosis, there could be errors in the dividing of sex cells.

There are other types of Asexual Reproduction:

  • Sporulation
  • Parthenogenesis
  • cloning
  •  Binarygrultiple fission
  • Budding
  • Vegetative Propagation ragmentation/Regeneration
  • How the sperm moves:
  •  Spermatogenesis in the testis
  •  Maturation in the epididymis
  • Carried a long vas deferens
  • Fructose for energy and protective mucus picked up at seminal vesicle
  •  Prostate adds fluids to neutralise acid
  •  Ejaculation through the penis.

EVOLUTION

As known, all offspring have some traits different from their parents. This could be due to RANDOM DESCENT WITH MODIFKATION OR ADAPTABILIT TO ENVIRONMENT.

  •  Darwin suggested that Natural Selection takes place, where organisms share traits to be able to sunive in their respective habitats. For instance, insects could start changing o lours to camouflage and not be en by predators. This is volution. Sometimes, this could pen due to external factors. instance, fishers are constantly ting bigger fish. Hence smaller breed even smaller fish. evolution too. In addition, mals changed and bore that changed. It is that the ancestors and dolphins
  • were able to walk. Which brought in Darwin’s theory, that all life comes from ow common ancestor, which he took to be bacteria. He said that these bacteria could have been formed (not born) by molecular reactions. They could also have arrived by an asteroid that hit the Earth.
  • Application of theory of Evolution: Why are grasslands turning into deserts?
  • When grass existed, wild animals dropped their dung and urine to allow the grass to thrive, tilled the grass with hooves, and ate excess grass. With their disappear grasslands started to die. Allan savory, a biologist from Zimbabwe, found this to be true.
  • How did bacteria come together to create organisms?
  • Scientists say that this is due to cooperarion. Earlier, they say, bacteria operated individually, over time, they came together, to form superorganisms. They specialized, and began to rely so much on each other they could not disband. They divided and formed colonies and hence organisms.

                        

BIOTECHNOLOGY 

  • Biotechnology is the exploitation of biological processes for industrial and other purposes.
  • It involves input from:
  •  Engineering
  • Cell and Molecular Biology
  • Computer Science
  • Bio chemistry
  • Virology
  • Genetics
  • Microbiology
  • Physiology
  • EtC.

Recombinant DNA Technology works by taking BNA from 2 different sources and combining that DNA into a single moleare when that DNA is reproduced, DNA cloning takes place. Recombinant DNA is a molecule that combines DNA from 2 different sources. There are 6 steps of Recombinant DNA

  • Isolating
  •  cutting
  •  Joining
  •  Transforming
  • Cloning
  •  Selecting

DNA Cloning has been taken to many levels. For now, let’s focuS on E. Coli. DNA cloning is creating identical copies of a piece of DNA.

Hybrid Animals are examples of animals created by two different species of animals. Examples:

  •  Through Biotechnology, sequencing the human genome (all the genes + some extra) that help create an organism). The first human genome was sequenced in 2003 . It took 20 years to do 50 , and cost over 3 billion dollars.
  •  In sequencing a human genome, first, the genes are broken down into smaller pieces. Then, scientists use enzymes to mate thousands of replicas of the same gene. To read this, scientists give a distinct colour to each letter that shows a base $(A, C, T, G)$. A mixture of these colored letters and enzymes is then added to the genome trying to be read. On each of the genome stop, one of the $c$ loured letters binds to its pposite $(A-T$ and $(-G)$. cientists take pictures of these colours. Seeing the rider of the colour allows – read the sequence. muter programs “stich” ether the millions of ers. Scientists are still! orking on how to decipher information the sum of these genes determines our characteristics.
  • Another of the feats of Biotechnology is 30 organ Prising. 3P organ pRinting is the use of a 30 printer to “print” living organs.
  • First, a scan of the patient is made, detecting how the organ needs to look This is made by a rotating Scanner.
  • Then, a sample of cells is used to make a “living ink”. This is slowly poured down, and using a computer program, and a 3D printer, the organ is sharp It is then placed in the incubator, which provides a similar environment to that of the human body

BLOOD GROUP CHART (can take from)

Scroll to Top