The Circulatory System (Edexcel A (SNAB) A Level Biology)

Exam Questions

45 mins5 questions
1a
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2 marks

The diagram shows a human capillary.

gw9zImq1_structure-of-a-capillary

State and explain one feature of capillaries visible in the diagram that helps them to carry out their function.

1b
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2 marks

Capillaries form part of the circulatory system of some organisms.

Explain why multicellular organisms, such as humans, require a circulatory system while single-celled organisms, such as bacteria, do not.

1c
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4 marks

The circulatory system is an example of a mass transport system. 

(i)

Define the term mass transport system.

(1)

(ii)

Describe how the lungs and circulatory system work together to allow efficient mass transport in the body.

(3)

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2a
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4 marks

The diagram shows an image of a micrograph of a cross section through two mammalian blood vessels.

Artery and vein structure

(i)

 Identify the the type of blood vessels labelled X and Y.

(2)

(ii)

Describe one structure of each vessel and explain how this structure relates to its function.

(2)

2b
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5 marks

The graph below shows pressure changes in the blood vessels as the blood passes through different sections of the mammalian circulatory system.

8-1-fig-2-2

Explain the blood pressure in the following sections of the graph:

(i)

The arteries and arterioles

(3)

(ii)

The capillaries

(1)

(iii)

The venules and veins

(1)

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3a
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2 marks

The main component of both blood and tissue fluid is water.

Explain one property of water that makes it an ideal transport medium for organisms with a transport system.

3b
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2 marks

Explain the role of hydrogen bonding and its importance in transporting water.

3c
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3 marks

Water is described as a dipole in nature.

With reference to covalent bonding, explain the dipolar nature of water molecules.

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4a
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1 mark

The graph below shows changes in pressure in parts of a human heart during one second.

State the time at which the semi-lunar valves open.

ventricles-aorta

4b
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1 mark

Use the graph to calculate the heart rate in beats per minute (bpm).

4c
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2 marks

Valves are important for maintaining blood pressure in the heart. 

Using a specific example, explain how they work.

4d
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4 marks

The contractions of the heart muscle leading to pressure changes.

(i)

Name which part of the heart causes the increase in pressure in the aorta.

(1)

(ii)

Explain why this increase is important for the organism.

(3)

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5a
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2 marks

A group of scientists were investigating heart rate. The scientists used Daphnia fleas to find out the effect of Sotalol beta blocker on heart rate. 

The Daphnia were divided into two groups: one group was administered Sotalol every day for 7 seven days. The other group acted as a control. The scientists measured the heart rates of both sets of the Daphnia after exposure to the drug or control substance.

Describe how the control group should have been treated. 

5b
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4 marks

Using live organisms during experimentation raises some ethical issues.

(i)

Discuss the ethical issues when using organisms such as Daphnia.

(2)

(ii)

Name two precautions that should be taken when using live organisms in experimentation.

(2)

5c
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4 marks

The scientists then investigated how changing the concentration of Sotalol affected the heart rate of Daphnia.

The table below shows their results. 

Concentration of Sotalol (%) Heart rate of Daphnia (Beats per minute)
0 257
0.001 239
0.01 196
0.1 147
1.0 126
10 111
20 96

(i)

Calculate the percentage decrease in the heart rate of Daphnia for increasing concentration of Sotalol from 0% to 20%.

(2)

(ii)

The scientists used the percentage change in the heart rate of Daphnia to compare the results for the control group and experimental group.

Explain why they used percentage change as part of their analysis.

(2)

5d
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3 marks

After reading the scientists’ report, a journalist reported that:

"Sotalol: The next best drug for your heart: Beta blockers decrease heart rate!”

Evaluate this statement.

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