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Biology (B3) End of Topic - Coggle Diagram
Biology (B3) End of Topic
Principles of Organisation
A cell is a fundamental building block for all organisms
A tissue is a group of cells with similar structure and function to one another
An organ is a aggregation of tissue with a specific function(s)
An organ system is a series of organs paired together to perform a specific bodily function.
The Human Digestive System
The Mouth
First part of the digestive system
Breaks down food mechanically and chemically
Houses the amylase enzyme (breaks down starch)
The Oesophagus
Second part of the digestive system
Uses peristalsis to move down its tubular structure towards the stomach
The Stomach
Third part of the digestive system
Protein digestion begins here (via protease)
Bacteria is also killed within the stomach via the hydrochloric acid inside
The Liver
Bile is produced here
Pancreas
Produces and excretes digestive enzymes
Gallbladder
Bile is stored here
The Small Intestine
The small intestine is where newly-broken-down, small, soluble food molecules are absorbed into the blood stream
Fourth part of the digestive system
The small intestine (expanded)
Adapted for its function (diffusion of small, soluble molecules): very large surface area, millions of villi present within and a thin membrane.
Villi assist in the absorption of molecules because of they increase surface area massively
Enzymes ("Biological Catalysts")
The structure of enzymes can be represented with the "lock and key" theory.
An enzyme breaks down substrates at the enzymes' active site
Enzymes are always complementary to their substrate.
When an enzyme's temperature increases past its optimum temperature, it will eventually denature.
Decreasing an enzymes temperature will massively decrease its rate of reaction.
Different enzymes have a different pH that they can naturally reside in, a pH too high or low can denature the enzyme.
Bile
Bile is produced within the liver and stored in the gallbladder
Bile has 2 main functions: to neutralise the pH of the stomach's acid to allow lipase to work there and to emulsify lipids, increasing their surface area massively.
Required practical 5 (effects of pH on amylase)
Amylase breaks down starch molecules into glucose
To begin the experiment, we must place one drop of iodine solution in each well of a spotting tile
Secondly, three test tubes are accumulated. One test tube will have 2cm^3 of amylase solution, one will have 2cm^3 of starch solution and the last will have 2cm^3 of a buffer solution to manage pH.
Thirdly, all test tubes should be placed in a water bath (used to manage temperature) at 30 degrees which is the optimum temperature for amylase
Fourth, we combine the three separate solutions into one test tube where they are mixed with a stirring rod. A stopwatch will then be started.
After a short period of time, the stirring rod will be used to transfer a drop of the solution to the spotting tile, where the iodine solution will determine if the starch has been broken down.
We continue to transfer droplets every 30 seconds until the iodine solution remains orange.
We will then repeat the whole experiment with different pH buffer solutions.
Food Tests
Benedict's Test
Used to test for the presence of 'reducing sugars'
Quantitive test. If positive for large amounts of reducing sugars, solution will turn brick red
No colour change (blue) if negative
Drops of Benedict's solution are added to a food solution within a test tube, this test tube is then placed within a beaker of hot water.
Iodine Test
Used to test for the presence of starch.
Drops of iodine are placed into a food solution.
Will remain orange if negative, blue/black if positive.
Buiret Test
Test for proteins
Will remain blue if negative, lilac if positive
Emulsion Test
Test for lipids
Performed by adding drops of ethanol to an unfiltered food solution
Cloudy emulsion will form if positive
The Heart
The heart is referred to as a 'double pump'
Diagrams of the heart are flipped!
Oxygenated blood enter the heart from the lungs via the pulmonary vein
The heart is tasked with carrying deoxygenated blood to the lungs, back to the heart and then its pumped around the rest of the body
Deoxygenated blood enter the heart via the superior vena cava
Deoxygenated blood leaves the heart via the pulmonary artery
Oxygenated blood leaves the heart via the aorta
The heart's pacemaker cells are tasked with regulating heartbeat, they are located within the right atrium
Blood Vessels
Arteries are blood vessels that carry blood away from the heart, they have a narrow lumen and carry blood at high pressures because of thick, elastic, muscular walls
Veins are blood vessels that carry blood towards the heart, they have a relatively large lumen and valves in order to stop back flow (this happens at low pressure)
Capillaries tasked with exchanging substances between cells, they have thin walls to allow substances to pass through them, such as oxygen
The Lungs
The human respiratory system begins at the mouth where oxygen is breathed. Second is the trachea (windpipe), then the bronchi, bronchioles and finally the alveoli.
Deoxygenated blood is pumped to the lungs via the pulmonary artery
The lungs are filled with tiny air sacs called alveoli which are responsible for the diffusion of gasses into the surrounding capillaries.
Properties of a good diffusion surface: Large surface area, thin surface, short distance for substances to travel
Blood
The blood contains blood plasma, red blood cells, white blood cells and platelets
The platelets clot the blood and form scabs, the red blood cells carry oxygen via the haemoglobin, the white blood cells digest pathogens and blood plasma carries waste substances
Cancer
Benign tumours are groups of uncontrollably dividing cells that are non-harmful and do not invade surrounding tissue
Malignant tumours are groups uncontrollable dividing cells that break off and are transported through the body through the bloodstream and/or lymph system, they invade surrounding cells and can be very harmful.
Factors such as drinking, exposure to radiation, carcinogens and even genetics can increase risk of cancer
Cardiovascular Diseases
Cardiovascular diseases are non-communicable (cannot be spread from person to person)
Coronary heart disease is caused by a buildup of fatty substances within the coronary artery, this decreases the flow of blood to the heart and can therefore starve the heart of oxygen (resulting in a heart attack)
Coronary heart disease can be treated with either stents or statins. Statins are a drug that lowers cholesterol and therefore fatty buildup, they have to be taken regularly and can have side effects. A stent is a metal mesh that is implanted into the coronary artery, it allows blood to flow through the artery.
When a heart valve becomes faulty/leaky. It can be replaced with either an animal valve or a mechanical valve, a mechanical valve is effective as it can last a lifetime, however, a clicking noise is produced also. Animal valves will not last as log but will not click and drugs aren't required to be taken.
Risk Factors and Epidemiology
Epidemiology is the study of patterns of disease to determine risk factors
A causal mechanism is a way in which a risk factor causes something to happen
Translocation and Transpiration
Translocation is the movement of dissolved sugars in any direction throughout a plant's phloem tissue
Transpiration is the movement of water from a plants roots to its leaves via the xylem
Stomata lie on the surface of leaves, they are very small holes that allow gasses such as oxygen to leave the plant however they can also be responsible for the loss of water in the plant
Guard cells surround the stomata and allow them to open and close when necessary
Every phloem cell has a companion cell filled with mitochondria which provides the energy needed for translocation
Xlyem contain lignin which gives the plant support and have no internal organelles to maximise water flow
Rate of transpiration can be measured with a potometer with factors such as wind intensity, temperature, humidity and light intensity affecting the rate of transpiration
Stomatal Density = Number of Stomata in View / Area of Sample
Plant tissue, organs and organ systems
Most plants have 3 organ systems: the reproductive system, the shoot system and the root system
The surface of a leaf contains epidermal tissue which allows light to pass through it to the palisade cells
A plant's spongy mesophyll have large spaces between its cells to let gas through
Palisade cells contain many chloroplasts; they are responsible for photosynthesis
A waxy cuticle on a plant simple reduces the amount of water lost.
Red Blood Cells
Biconcave shape - Larger surface area
No nucleus - Can contain more haemoglobin
Contains haemoglobin - Can bind with oxygen
White Blood Cells
Tasked with engulfing and digesting PATHOGENS
Cytoplasm allows the cells to change shape easily to engulf pathogens