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Questions

Q1.

Read through the following passage on the cardiac cycle, then write on the dotted lines the most appropriate word or words to complete the passage.

The cardiac cycle consists of three stages: atrial systole, ventricular systole and

... .

During atrial systole, the ... contract and the

... are relaxed. The ... valves are open.

During ventricular systole, the ... open as oxygenated blood is

forced out of the heart through the aorta to the body and through the pulmonary

... to the lungs.

(Total for question = 6 marks)

Q2.

An investigation was carried out to study the effect of caffeine on the heart rate of a chicken embryo.

The heart from a chicken embryo was removed and placed in a glucose solution. The heart rate was determined and recorded as the base heart rate.

The experiment was repeated using glucose solutions containing five different concentrations of caffeine.

The heart rate was determined and recorded as a percentage of the base heart rate for each solution.

(2)

(a) (i) Suggest why glucose was included in the solutions.

(2)

...

...

...

...

...

...

(ii) Suggest how the caffeine solutions were prepared to obtain valid results.

(1)

...

(3)

...

...

(iii) State how these results could be made more reliable.

(1)

...

...

(iv) Using the information in the graph, describe the effect of caffeine on the heart rate of the chicken embryo. (3) ... ... ... ... ... ... ... ... ...

(b) (i) Describe how this investigation could be carried out using Daphnia instead of chicken

(4)

...

...

...

(ii) Suggest one ethical issue in the use of chicken embryos in this investigation.

(1)

...

...

...

...

(Total for question = 12 marks)

Q3.

Blood is carried around the body of many animals in different types of blood vessels. The structures of these blood vessels relate to their function.

(a) The table below refers to the structure of capillaries and veins. If the statement is correct, place a tick ( ) in the appropriate box and if the statement is incorrect, place a cross ( ) in the appropriate box.

(b) Semilunar valves and elastic fibres are found in the aorta. For each of these structures, describe its location in the aorta and explain its function.

(5)

... ... ... Elastic fibres (3) Location ... Function ... ... ... ... ...

(Total for question = 9 marks)

Q4.

There are many venomous (poisonous) snakes in the world. Many of the venoms from these snakes affect the blood clotting process.

*(a) Describe the blood clotting process.

(6)

...

(b) Factor Xa is a clotting factor present in human blood.

An experiment was carried out to investigate the time taken for human blood to clot in the presence of different masses of Factor Xa. The experiment was repeated using snake venom in place of Factor Xa.

The graph below shows the results of these experiments.

(i) Using the information in the graph, describe the effect of the snake venom on the clotting time of human blood.

(3)

...

...

...

...

...

...

(ii) Suggest why the clotting time of the human blood with snake venom added was compared with the clotting time in the presence of Factor Xa.

(7)

...

...

...

(c) The component of the snake venom that affects blood clotting is an enzyme.

(i) Describe the structure of an enzyme.

(3) ... ... ... ... ... ... ... ...

(ii) Suggest how the enzyme in the snake venom could be involved in the blood clotting process.

(2) ... ... ... ... ... ... ... ...

(Total for question = 13 marks)

Q5. Blood clots can form if the lining of an artery becomes damaged.

(8)

statement about the blood clotting process.

(i) A platelet

(1)

A is a protein that forms an insoluble mesh to trap red blood cells

B is an enzyme that converts prothrombin into thrombin

C is a cell fragment that releases thromboplastin

D is a cell fragment that releases fibrinogen

(ii) Thrombin is

(1)

A an enzyme that changes fibrinogen into fibrin

B an enzyme that changes fibrin into fibrinogen

C an insoluble protein that forms a mesh to trap red blood cells

D a protein that sticks to collagen in damaged walls of arteries

(iii) Fibrinogen is

(1)

A an insoluble protein that forms a mesh to trap red blood cells

B a soluble plasma protein

C an enzyme that converts prothrombin into thrombin

D a clotting factor released by platelets

(b) A stroke can be caused by cardiovascular disease (CVD) affecting arteries leading to the brain. Callum's family has a history of strokes.

(i) Explain why a blood clot in an artery leading to the brain could cause a stroke.

(9)

...

...

(ii) Suggest two lifestyle changes Callum could make to reduce his risk of suffering a stroke in

later life.

(2)

1 ...

...

2 ...

...

(Total for Question = 8 marks)

Q6.

Atherosclerosis is responsible for many deaths that result from cardiovascular disease (CVD).

The diagram below shows an external view of a human heart. The position of an atheroma (plaque) is shown and a region of dead heart muscle is shaded.

(a) (i) Explain how the structure of the aorta relates to its function.

(3)

...

(10)

... ... ... ... ... ...

(ii) Describe two differences between the structure of a capillary and the structure of a vein.

(2) 1 ... ... ... 2 ... ... ...

(b) (i) Suggest how the location of the atheroma results in the position and size of this region of dead heart muscle.

(3) ... ... ... ... ... ... ... ...

(ii) On the diagram below, shade an area to show the position and size of dead heart muscle, if the atheroma occurred at position B.

(11)

(Total for question = 10 marks)

Q7.

Cardiovascular disease (CVD) is responsible for many deaths.

*(a) One cause of CVD is atherosclerosis. Describe how atherosclerosis develops.

(4)

...

...

...

...

...

...

...

...

...

...

...

...

(12)

The genotype of some individuals causes them to be more at risk of developing CVD. One gene

that influences this risk is the KIF6 gene. Carriers of the 719 Arg allele of this gene are more at

risk of CVD.

(i) Explain the meaning of the term genotype.

(1)

...

...

(ii) Explain the meaning of the term allele.

(1)

...

...

(c) Give two factors, other than genetic factors, that increase the risk of developing CVD.

(1)

1

...

2

...

(d) Trials have shown that plant statin therapy is more effective in 719 Arg carriers than in non-carriers of this allele.

Describe the risks of using plant statins to treat CVD.

(2) ... ... ... ... ... ...

(Total for question = 9 marks)

(13)

Cardiovascular disease (CVD) is responsible for many deaths. One cause of CVD is atherosclerosis.

The photograph below shows a section through an artery with a plaque (atheroma) from a patient with CVD.

(a) Calculate the increase in the thickness of the artery wall where the plaque is located. Take

your measurements along the line labelled X and Y. Show your working.

(3)

Answer ...

(b) The plaque often increases in size and can block the artery. If the artery supplying blood to the heart becomes blocked, blood no longer flows to the heart muscle cells. Shortly after the loss of blood flow, heart muscle cells stop contracting and start to die.

In the heart muscle cells, energy (ATP) is made available from respiration.

The graph below shows how the energy (ATP) available to heart muscle cells changes with time, after the loss of blood flow.

(i) Using the information in the graph, describe how the energy (ATP) available to the heart muscle cells changes with time after the loss of blood flow.

(2)

(14)

...

...

...

...

...

(ii) Suggest why there are changes to the available energy (ATP) in the heart muscle cells following the loss of blood flow.

(2) ... ... ... ... ... ...

(iii) About 8 minutes after the loss of blood flow, the heart muscle cells no longer contract. After about 20 minutes, the heart muscle cells begin to die.

Using the information in the graph and your own knowledge, suggest explanations for the timings of these two events.

(3) ... ... ... ... ... ... ... ...

(iv) If blood flow is restored within 30 minutes, most heart muscle cells will eventually recover. Suggest an explanation for this recovery.

(2)

(15)

...

...

...

(Total for question = 12 marks)

Q9.

(a) Read through the following passage about the heart and its major blood vessels, then write on the dotted lines the most appropriate word or words to complete the passage.

(5)

The mammalian heart consists of four chambers, two upper chambers called

... and two lower chambers called ventricles.

The ... carries oxygenated blood away from the ...

ventricle to the cells of the body and the pulmonary ... carries

deoxygenated blood to the lungs. The ... returns deoxygenated

blood back to the heart from the body.

(b) The diagram below shows the structure of the heart.

Suggest which stage of the cardiac cycle is shown in the diagram and give a reason for your answer.

(2)

(16)

...

...

...

...

...

(Total for question = 7 marks)

Q10.

An amoeba is a single-celled organism that lives in water. Gas exchange in an amoeba occurs between the water and the cytoplasm.

The photograph below shows an amoeba, as seen using a microscope.

*(a) Using the information shown in the photograph and your own knowledge, suggest how gas exchange occurs in an amoeba.

(17)

...

...

...

...

...

(b) Suggest how oxygen passes from the cell membrane into the centre of an amoeba.

(2)

...

...

...

...

(Total for question = 6 marks)

Q11. Many animals have specialised organs for gas exchange and transport.

*(a) The diagram below shows the lungs of a mammal.

Describe and explain how the lungs of a mammal are adapted for rapid gas exchange.

(5)

...

...

...

(18)

... ... ... ... ... ... ... ...

(b) Daphnia have a circulatory system with a heart that pumps blood into cavities surrounding

their organs.

The photograph below shows the location of the heart in a Daphnia.

(i) Suggest how the heart of a Daphnia enables organs to carry out effective gas exchange.

(2) ... ... ... ... ... ... ...

(19)

Suggest how this type of circulation enables mammals to carry out effective gas exchange. (3) ... ... ... ... ... ... ... ...

(Total for Question = 10 marks)

Q12. Some species of flatworm are found in freshwater streams.

Flatworms obtain oxygen from the water through the surface of their bodies. The diagram below shows the structure of flatworms.

(a) Using the diagram and your knowledge of gas exchange surfaces, explain how the structure of a flatworm is adapted to obtain oxygen from the water.

(20)

... ... ... ... ... ...

(b) The table below shows the relationship between the temperature of water and the solubility of oxygen in water.

(i) Describe the relationship between the temperature of the water and the solubility of oxygen in water. (2) ... ... ... ... ... ... ... ... ... ... ... ...

(ii) Using the information in the table and your knowledge of gas exchange and enzymes, suggest why flatworms are often found in water at a temperature of about 15 °C .

(21)

... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...

(c) Flatworms do not have a heart or a circulatory system.

Explain why many animals need a heart and a circulatory system.

(22)

... ...

... ...

(Total for Question = 11 marks)

Q13.

The photograph below shows Daphnia (a water flea). Daphnia can be used to

investigate the effect of chemicals on heart rate.

Explain why many small animals, such as Daphnia, have a heart.

(3)

...

...

...

...

...

...

...

...

(23)

Q14.

* During the cardiac cycle, muscles in the walls of the atria and ventricles contract and relax.

The graph below shows the changes in pressure that occur in the left side of the mammalian heart during one cardiac cycle.

* During this cardiac cycle, the changes in pressure that occur in the left atrium and in the left ventricle are different.

Using the information in the graph and your own knowledge, explain these differences.

(5)

...

...

...

...

(24)

...

...

...

...

...

...

...

...

...

...

Mark Scheme

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