Exam questions Flashcards
1
Q
describe how the atrioventricular ventricular valves work during one cardiac cycle
(2)
A
- valves are open to allow blood to flow from the atria to the ventricles/open during atrial systole/when atria contract
- valves close when ventricles contract/ventricular systole
- valves prevent backflow of blood into the atria during ventricular systole
2
Q
explain why the semilunar valves close (2)
A
- the pressure in the aorta is higher than the pressure in the left ventricle during diastole
- therefore forcing blood around the body rather than flowing back into the ventricle
3
Q
explain why the mammalian heart is divided into a right and left side (2)
A
- keeps deoxygenated and oxygenated blood separate
- separation results in as much oxygen as possible being carried to the {tissues/cells}
- blood needs to be pumped at different pressure (lower pressure to the lung + higher pressure to the body)
4
Q
describe the structure of the mammalian heart (5)
A
- four chambers
- 2 atria on top 2 ventricles below
- left and right separated by a septum
- reference to cardiac muscle
- thickness of the ventricles walls
- position of atrioventricular valves
- position of semilunar valves
- position of the aorta/pulmonary artery
- position of vena cava/pulmonary vein
- reference of coronary arteries
5
Q
explain the difference in thickness of the wall of the right atrium and the wall of the right ventricle (3)
A
- right atrium has less muscle
- reference to the thickness of the walls being related to pressure
- right atrium pumps blood to right ventricle
- right ventricle pumps blood to the lungs
6
Q
in mammals, blood passes through the heart twice for each circulation of the body.
suggest how this type of circulation enables mammals to carry out effective gas exchange (3)
A
- right side of the heart pumps blood to the lungs and the left side of the heart pumps blood to the body
- separation of oxygenated and deoxygenated blood
- idea of maintaining gas {concentration/diffusion} gradient
- lower pressure in right side of the heart protects delicate structures e.g. capillary or alveoli
- high pressure allows for {rapid} {mass flow/supply of oxygen} to body cells
7
Q
describe the role of the heart valves in the cardiac cycle (6)
A
- atria contact/atrial systole
- av valves open so blood flows from atria to ventricles
- ventricles contract/ventricular systole
- av valves close to prevent backflow of blood into the atria
- sl valves open so blood {leaves the ventricles/enters pulmonary artery/aorta}
- ventricles relax/ventricular diastole
- sl valves close
- to prevent the backflow of blood into the ventricles from aorta/pulmonary arteries
8
Q
explain the function of the elastic fibres in the aorta (2)
A
- allow stretch and recoil
- in order to maintain blood pressure
9
Q
explain how the structure of an artery wall is adapted both to withstand and to maintain high blood pressure (3)
A
- more collagen provides strength to withstand pressure
- contraction of muscles allow narrowing of the {artery/lumen}
- elastic fibres allow stretch and {recoil/lumen returning to original size}
10
Q
explain why blood clot formation in capillaries could cause tissues to die (2)
A
- lumen of capillaries is blocked
- preventing the supply of {oxygen/glucose} to tissues/cells
- stopping respiration/anaerobic respiration causes a build up of lactic acid
11
Q
explain how the structure of a vein relates to its function (4)
A
- valves prevent backflow of blood
- smooth endothelium to reduce resistance to blood flow
- large lumen to reduce resistance of blood flow back to the heart
- thin walls to maintain lower blood pressure
12
Q
compare and contrast the structure of the aorta with the structure of the pulmonary artery (2)
A
similarities:
- both have walls containing {elastic fibres/muscle cells/collagen layer}
- both have a valve
differences:
- aorta has a {wider lumen/thicker walls/more collagen/ more muscle tissue}
-aorta has branches to more organs
13
Q
explain how arteries are adapted to accommodate sudden increases in blood flow (2)
A
- elastic fibres can {stretch/expand}
- therefore {widening the lumen} of the artery
- walls contain collagen to increase the strength
14
Q
explain how arteries are adapted to reduce resistance to blood flow (2)
A
- inside of artery is lined with the smooth endothelium
- to reduce friction
15
Q
explain why the total surface area of the capillaries needs to be so high (2)
A
- more plasma is able to leave the capillaries
- results in faster diffusion
- more capillaries are in contact with the cells (short diffusion distance)
16
Q
describe how tissue fluid is formed (2)
A
- hydrostatic pressure generated by the heart
- water and low molecular mass solutes forced out of capillaries
17
Q
describe how the structure of the aorta is related to its function (4)
A
- wall of the aorta is {thick/contains collagen}
- to withstand pressure
- wall of the aorta contains {elastic fibres}
- allowing the wall of the aorta to stretch and recoil
- valves present at the start of the aorta
- prevents backflow of blood during diastole
18
Q
explain why many animals need a heart and a circulatory system (4)
A
- heart is needed to pump blood around the body
- reference to mass flow
- animals have a small surface area to volume ratio
- circulatory system is needed to overcome the limitations of diffusion
- transport of a named molecule in the blood
- idea that mammals have a high metabolic rate
19
Q
explain how the properties of water molecules result in surface tension (3)
A
- water molecules are polar
- therefore form hydrogen bonds
- therefore are cohesive
- which result in an inward force at its surface
20
Q
explain how the dipolar nature of water is essential for living organisms (2)
A
- water can form hydrogen bonds
- water is a solvent so polar molecule can {dissolve/be transported} in water
- hydrogen bonds holds water molecules together as a liquid so it can move in a mass flow system
21
Q
describe how very high blood pressure could result in atherosclerosis (3)
A
- high blood pressure damages the endothelium of the artery
- cases an inflammatory response
- {white blood cells/cholesterol} accumulates/atheroma forms
- calcium salts/fibrous tissue builds up/formation of plaque
22
Q
explain how atherosclerosis in one part of an artery could increase the likelihood of it developing in another part of the same artery (2)
A
- {plaque/atherosclerosis} narrows the lumen of the artery
- increasing blood pressure more
23
Q
explain why a stent is used in the treatment of atherosclerosis in a coronary artery (3)
A
- to widen the lumen of the coronary artery
- so that more blood can flow to the heart {cells/muscle}
- for respiration in the heart muscle
24
Q
explain how atherosclerosis can result in damage to the heart muscle (4)
A
- formation of blood clot/thickening of the artery walls
- therefore {blocks/narrows} the coronary arteries
- reduces blood flow
- depriving the heart muscle of {oxygen/nutrients}
25
explain how an increase in dietary salt can lead to the development of atherosclerosis (5)
- high salt causes an increase in blood volume
- causing high blood pressure which damages the endothelium in arteries
- this causes an inflammatory response
- cholesterol deposits lead to atheroma/calcium deposits lead to formation of plaque
- therefore arteries {narrow/loose elasticity/ harden}
26
describe how atherosclerosis develops (4)
- damage to endothelium of the artery
- inflammatory response
- white blood cells gather in the area
- build up of cholesterol
- formation of atheroma/plaque
- reference to calcium salts/fibrous tissues
- loss of elasticity/ narrowing of lumen of artery
- self perpetuating process
27
explain why raised lipid levels in the blood may increase the risk of developing CVD
(4)
- increased risk of {cholesterol deposits/higher blood cholesterol}
- leads to formation of {atheroma/plaque/atherosclerosis}
- increased risk of blood clot forming
- loss of elasticity to artery/lumen narrowing
- increasing blood pressure
28
explain the role of blood clots in heart disease (3)
- blood clots can block coronary arteries
- reducing the {flow of blood/supply of oxygen} to the heart tissues
- resulting in heart attack
29
describe the role of thrombin in blood clotting (3)
- thrombin is an enzyme
- catalyses the conversion of fibrinogen into fibrin
- fibrin mesh traps {platelets/red blood cells} to form a clot
30
describe the role of prothrombin in the blood clotting process (3)
- to be present in the blood at all times
- needed to make thrombin
- which is an {enzyme/catalyst}
- so fibrinogen can be converted into fibrin
31
explain why a blood clot in an artery leading to the brain could cause a stroke (3)
- reduced blood flow
- less {oxygen/glucose} reaches the brain
- less/no aerobic respiration
- less/no ATP produced
- brain needs lots of ATP/energy to function
- lactic acid produced from anaerobic respiration
- lactic acid inhibits enzymes/is toxic
32
describe the blood clotting process (4)
- idea of cascade of events leading to clot
- thromboplastin starting the cascade
- conversion of prothrombin into thrombin
- thromboplastin/thrombin is an enzyme/catalyst
- conversion of fibrinogen to fibrin by thrombin
- requirement of calcium ions/vitamin K
- platelets getting trapped in mesh
33
devise a procedure to compare the effects of caffeine concentration of the heartbeat of daphnia (4)
- daphnia immobilised on a cavity slide
- range of different caffeine concentrations (0, 0.1, 0.5)
- acclimatisation/using a microscope/method of counting
- record heartbeat before (in water) then after (in caffeine solution)
- controlled variable for the caffeine (concentration/volume)
- controlled variables (temperature/length of count time/same species/age)
- repeats carried out and calculate mean
34
explain how the structure of glycogen allows it to be an energy store (3)
- polymer of glucose
- to provide glucose for respiration
- {branched/contains 1,6 glycosidic bonds/has many terminal ends} for rapid hydrolysis
- compact to allow large amounts of glucose/energy to be stored in a small space
35
describe the structure of starch (3)
- polysaccharide made of alpha glucose units
- units in the chain are joined by 1,4 glycosidic bonds
- contains unbranched molecule/amylose and branched chain/amylopectin
- branches are joined to chains by 1,6 glycosidic bonds
36
compare and contrast the structure of amylose with the structure of amylopectin (3)
similarities:
- both polymers of alpha glucose
- both contain 1,4 glycosidic bonds
differences:
- amylose has 1,4 glycosidic bonds only whereas amylopectin has 1,4 and 1,6 glycosidic bonds
- amylose is an unbranched molecule and amylopectin is a branched molecule
37
compare and contrast the structure of glucose with the structure of glycogen (3)
similarities:
- both contain alpha glucose
- both contain C,O and H only
differences:
- glucose is a monosaccharide whereas glycogen is a polysaccharide
- glycogen has 1,4 and 1,6 glycosidic bonds whereas glucose does not have glycosidic bonds
38
describe the structure of a triglyceride (2)
- one glycerol and three fatty acids
- joined by ester bonds/esterification
39
state two differences between the structure of a saturated lipid and an unsaturated lipid (2)
- saturated lipids have no carbon to carbon double bonds whereas unsaturated lipids have carbon to carbon double bonds
- saturated carbons have straight chains and unsaturated have kinks in their chains
40
describe an experiment that could be carried out to make a valid comparison of the vitamin C content of three fruits (6)
- obtain the juice from the three fruits
- controlled variable - age of fruit, volume of DCPIP, ripeness
- reference of DCPIP
- description of titration
- colour change from blue - colourless (when juice is added to DCPIP)
- record volume needed for colour change
- ref to standard deviation/calibration curve to determine vitamin C concentration
- repeat experiment and calculate mean
41
explain the role of antihypertensive drugs in reducing the risk of atherosclerosis (4)
- antihypertensive drugs lower blood pressure
- lower bp reduces the risk of damage to the endothelium of an artery
- reduced risk of inflammatory response
- reduced risk of {atheroma/plaque} formation
42
state three possible side effects of taking drugs to reduce blood pressure (3)
- nausea
- dizziness
- muscle cramps
- kidney failure
43
explain why antioxidants in the diet reduce the risk of CVD (3)
- antioxidants reduce free radicals
- therefore {cell damage/damage to lining of blood vessels} is reduced
- reducing {plaque/atheroma} formation
44
explain the benefits of warfarin in the treatment of CVD (3)
- prevents formation of a blood clot/thrombus
- reduces effectiveness of platelets (reduces stickiness)
- less chance of artery blockage
- maintains oxygen supply to tissues
- less risk of a heart attack/stroke
45
explain why patients with CVD would take each of the following drugs
platelet inhibitory drugs such as aspirin (2)
Antihypertensives such as beta-blockers (2)
platelet inhibitory drugs - aspirin
- prevents platelets becoming sticky/activated
- prevents formation of blood clot/thrombus
-reducing risk of stroke
antihypertensives - beta-blockers
- reduces blood pressure
- reduces heart rate
- prevents muscles in vessel walls contracting
46
explain how anticoagulants can help reduce the effects of CVD (2)
- prevents the formation of a blood clot/thrombus
- reduces stickiness of platelets
- clotting factor is not synthesised/inhibited (fibrinogen/thromboplastin/prothrombin)
- risk of blood vessels becoming blocked is reduced
47
explain why statins reduce the risk of CVD (2)
- inhibit the synthesis/production of cholesterol of cholesterol in the liver
- reducing blood cholesterol levels
- raises HDL levels/increases HDL:LDL levels/lowers LDL levels
