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biology unit 2: organisation - Coggle Diagram
biology unit 2: organisation
specialised cells
sperm cell.
lots of mitochondria: major site of respiration to release energy for their journey.
long tail: propel the sperm to firlise the egg.
nulcues: contains one set of the genetic material.
arcosome: contains enzymes to allow sperm to penetrate outer layer of egg.
a muscle cell.
many mitochondria for energy, protein fibres that can contract.
plant cells:
xylem: arranged end to end but the end walls break down to form hollow tubes.
cell wall is strenghened by lignin.
phloem: end walls of cells allow sugar through by support the tubes.
arranged end to end in tubes.
root hair cell: lots of mitochondria for active transport of minerals. Long projection to increase the surface area to absorb water and minerals.
enzymes: biological catlysts.
lock and key theory. works at the optimum ph and temperature. They catalyse the breakdown of large insoluble food molecules into smaller soluble molecules.
digestive enzymes produced by specialised cells in glands and lining of gut. Protease, lipase and carbohydrase digest proteins lipids and carbohydrates.
required practicals: food tests
sugars: e.g glucose add benidicts reagent and heat in water bath for two minutes, if sugar is present it will turn brick red.
starch: iodine, will turn blue black if present.
protein: biuret reagent. if present it will turn purple.
amylase: carbohydrase that breaks starch into sugar (maltose) produced in salivary glands and in the pancreas.
protease: produced in stomach, pancreas and small intestine. breaks down proteins into amino acids or peptides.
lipase: produced in the pancreas and small intestine. breaks down lipids into fatty acids and glycerol.
bile
bile: made in liver and stored in the gall bladder. alkaline to neutralise HCL in stomach. emulsifies fat to increase surface area for enzymes. Increases rate fat is broken down by lipase.
.
required practical: effect of PH
test tube containing starch solution in test tube containing amylase into a water bath at 37*c.
after 5 mins add amylase solution to starch.
every 30 seconds take a drop and test it for starch using iodine.
record until starch fully digested. then repeat at different PHs.
independant variable: the PH. dependant variable: time taken for starch to be digested. control variables: temperature, conc and vol of starch and amylase.
blood.
made of plasma which contains: red blood cells - contain haemoglobin to bind to oxygen for respiration, don't contain a nucleus and are biconcave for a large surface area that oxygen can diffuse quickly across.
white blood cells - lymphocytes and phagocytes, can change shape, squeeze out blood vessels into tissue or engulf microorganisms.
and platelets - fragments of cells which trigger blood clotting.
vessels: arteries: take blood from heart to organs. thick walls of muscle and elastic fibres.
veins: blood from organs to heart. thinner walls and have valves to prevent backflow.
capillaries: substances produced by cells can pass into blood as it is narrow and one cell thick for a quick diffusion pathway.
heart.
atria: recieve blood from veins. Ventricles - pump blood out into arteries.
right atrium gets deoxygenated blood from the vena cava. - then pumped through the valves into the right ventricle - from here it is forced up the pulmonary artery towards the lungs where gas exchange takes place - oxygenated blood enters the left atrium via the left atrium via the pulmonary vein and down the left ventricle
gas exchange.
pulmonary artery - blood to lungs. air obtain through trachea. trachea divides into two tubes called the bronchi --> bronchioles. divide until form tiny air sacs called alveoli.
alveoli adaptations: large moist surface area, rich blood supply, close to blood capillaries so distances for diffusion is small. blood taken back to heart via pulmonary vein.
non communicable disease:
cancer is uncontrolled cell division which can form masses of cells called tumours. main types: benign - dont spread around the body. maligant - spread in the blood to different parts of the body forming secondary tumours.
cardiovascular disease: lack of exercise, smoking, high intake of saturated fat.
type 2 diabetes: obesity.
Liver and brain damage: excessive alcohol intake
lung diseases: smoking
Skin cancer: ionising radiation - e.g uv light
low birth rate in babies: smoking during pregnancy.
Brain damage in babies: excessive alcohol intake during pregnancy.
coronary heart disease. - layers of fatty material build up inside the coronary aterieries and narrow them.
treatment: stents - keep atereries open. statins - reduce blood cholesterol levels and slow down the rate at which fatty materials build up.
faulty valves: leak or preventing the valve opening fully. Can be replaced using biological or mechanical valves.
heart failure: donar heart can be transplanted. artifical hearts can be used to keep patients alive while waiting for a heart transplant or to allow the heart to recover.
plant tissues
epidermis - covers outer surfaces of the plant for protection.
palisade mesophyll - main site of photosynthesis in the leaf.
spongy mesophyll - air spaces between cells to allow gas diffusion
xylem vessels - transport water and minerals from roots to leaves, + supports the plant.
phloem vessels - transports dissolved food though the plant
meristem tissue - at tips of roots and shoots, produce new cells for groiwth.
loss of water from leaves is transpiration. water will evaporate and diffuse out of stomata.
factors that effect the rate of transpiration: - temperature - increase rate, as more enery is transferred to water to allow it to evaporate.
faster air flow increase the rate - blow away water vapour so more can evaporate.
increased light intensity. - cause stomata to open.
humidity - decrease rate as air contain more water vapour so concentration gradient for diffusion is lower.
translocation. movement of food through phloem tissue
