Topic 1 Biology Flashcards
(14 cards)
Name two properties of water that make it a good transport molecule.
Cohesive and good solvent due to dipole nature.
Why do multicellular organisms need mass transport systems? Name the mass transport system found in mammals.
Diffusion would be too slow as too great of a diffusion distance. The circulatory system.
Describe structure of each type of blood vessel and explain how this makes it adapted to its function.
Arteries: Narrow lumen. Muscular walls containing lots of elastic tissue and folded endothelium. So artery can cope under high pressure.
Veins: Wider lumen. Walls contain less muscle and less elastic tissue as under less pressure. contain valves to prevent backflow of blood.
Capillaries: Site of metabolic exchange. Capillary endothelium one cell thick for short diffusion distance. Vast network of capillaries makes large surface area for diffusion.
Outline cardiac cycle in 3 steps.
Atrial systole: Atria contract, forcing blood into ventricles through AV valves.
Ventricular systole: Ventricles contract, causing AV valves to shut and SL valves to open. Blood forced into pulmonary artery and aorta.
Cardiac Diastole: Atria and ventricles relax. SL valves shut and AV valves open.
Describe how you could find out the effect of caffeine on Daphnia heart rate.
- Make up 5 solutions of caffeine solution of diff concs. As well as control containing no caffeine.
- Place daphnia onto dimple on cavity slide. Pipette a few drops of caffeine solution onto it.
- Count number of heart beats in 20 seconds. Times by 3 to calc BPM.
- Repeat 10 times at each conc with different daphnia.
- Compare results to find out effect of caffeine conc on heart rate in daphnia.
Describe atheroma formation.
- Damage to endothelium caused by high BP causes inflammatory response.
- White blood cells and chemicals such as cholesterol build up. Causing a fatty atheroma to form.
- Fibrous tissues and calcium salts cause atheroma to become hard swelling known as plaque.
- Plaque narrows arteries, increasing BP. This leads to more plaque formation and therefore higher BP. This is a positive feedback loop.
Describe how blood clots form
- Damaged blood vessel releases thromboplastin.
- Thromboplastin and calcium ions convert prothrombin to thrombin.
- Thrombin converts soluble fibrinogen into insoluble fibrin.
- Fibrin creates mesh which traps platelets and red blood cells, forming a blood clot.
Explain how antihypertensives and statins work and outline benefits and risks.
Antihypertensives: lower BP by
1. Beta blockers reducing strength of heartbeat.
2. Vasodilators widening blood vessels.
3. Diuretics reducing blood volume
Advantages:can be used in range of combos and can be monitored by patient at home.
Disadvantages: palpitations, fainting, headache, fatigue and depression.
Statins: reduce LDL levels in blood.
Advantages: reduce risk of CVD by reducing risk of atheroma formation.
Disadvantages: muscle and joint pain, increased risk of diabetes, nosebleeds, nausea, headaches.
How do anticoagulants and platelet inhibitory drugs work? What are the risks and benefits of them?
Anticoagulants reduce blood clot formation
Benefits: stops new blood clot formation and prevents existing blood clots from growing.
Risks: Damage fetus if pregnant. Cause excessive bleeding if injured.
Platelet inhibitory drugs: type of anticoagulant that prevents platelets from clumping together.
Benefits: stops new blood clot formation and prevents existing blood clots from growing.
Risks: rashes, liver problems, excessive bleeding and diarrhoea
Describe structure of starch and how this makes it suitable for its function.
Amylose: unbranched chain of 1-4 glycosidic bonds. Compact so good for storage.
Amylopectin: branched chain containing 1-4 and 1-6 glycosidic bonds. Side branches allow for quick hydrolysis.
Starch is insoluble in water so good for storage as doesn’t affect osmotic balance of cell.
Describe structure of glycogen and how it makes it suitable for its function.
Similar structure to amylopectin except with many more side branches. This allows for quick glucose release.
Compact and insoluble so good for storage as doesn’t take up much space and does not affect osmotic balance of cell.
Large molecule so stores lots of energy.
Difference between saturated and unsaturated lipids and which has lower melting point.
Saturated: no double bonds in hydrocarbon chain.
Unsaturated: contains double bonds in hydrocarbon chain.
Unsaturated lipids have lower melting point as double bonds in chain cause kinks which prevent them from packing closely together.
Differences between HDLs and LDLs
HDLs: Mainly protein.
Transports cholesterol from body tissues to liver where it is recycled or secreted.
Reduces blood cholesterol when it is too high.
LDLs: Mainly lipid.
Transports cholesterol from liver to blood where it circulates until needed by cells.
Increases blood cholesterol when it is too low.
Describe tissue fluid formation.
Blood from heart enters the arteriole from the artery.
From the arteriole the blood enters capillaries where plasma is forced out of the capillaries, forming tissue fluid.
This tissue fluid bathes cells near to it where the cells will absorb nutrients and oxygen from the tissue fluid. As well as giving out waste.
The tissue fluid then moves back into capillaries by osmosis. However only about 80% of tissue fluid moves back into the capillaries and rest drains into blind-ended lymph capillaries.
It will then flow through lymph vessels and returns the lymph fluid to the blood via the thoracic duct in the neck, which empties into the vena cava.
The tissue fluid which did move back into the capillaries moves into the venule and then into the veins, where the deoxygenated blood is returned to the heart.
