Lifestyle, health and riskEdexcel A-Level Biology A: Topic test

20 questions, 54 marks

Edexcel A-Level Biology A

Lifestyle, health and risk topic test

Total 54 marks

Name

Class

Date

1
A cardiologist is explaining to a student how the two sides of the mammalian heart work together during each heartbeat.
(a)
Which statement explains why the atrioventricular valves close at the start of ventricular systole?
[1 mark]
AThe pressure in the aorta rises above the pressure in the left ventricle
BThe pressure in the ventricles rises above the pressure in the atria
CThe atria relax and their walls recoil, pulling the valves shut
DThe semilunar valves open and push the atrioventricular valves closed
(b)
Why is the muscular wall of the left ventricle thicker than the wall of the right ventricle?
[1 mark]
AThe left ventricle pumps deoxygenated blood, which is more viscous
BThe left ventricle pumps blood a greater distance to the lungs
CThe left ventricle receives blood from the atrium at a higher pressure
DThe left ventricle must generate a higher pressure to pump blood around the whole body
(c)
Describe the role of the semilunar valves during cardiac diastole.
[2 marks]
Total for question 1: 4 marks
2
A student compares a transverse section of an artery with a transverse section of a vein of similar external diameter taken from the same mammal.
(a)
Which feature would be seen in the wall of the artery but not in the wall of the vein?
[1 mark]
AA much thicker layer of elastic fibres and smooth muscle
BValves projecting into the lumen
CA wider lumen
DA lining of endothelium
(b)
Why do veins contain valves?
[1 mark]
ATo maintain a high blood pressure in the vein
BTo allow the vein wall to stretch and recoil with each heartbeat
CTo prevent backflow of blood because the pressure in veins is low
DTo allow oxygen to diffuse out of the blood into the tissues
(c)
Explain how the structure of a capillary makes it suited to the exchange of substances between the blood and the tissues.
[2 marks]
Total for question 2: 4 marks
3
A horse has a large body mass and a very high metabolic rate when galloping. Its muscle cells need a rapid supply of oxygen, glucose and fatty acids.
(a)
Explain why a large mammal such as a horse needs a heart and a circulatory system rather than relying on diffusion alone.
[3 marks]
(b)
The horse stores energy as triglycerides in adipose tissue. Describe how a triglyceride is synthesised and explain why triglycerides cannot be transported dissolved in blood plasma.
[4 marks]
Total for question 3: 7 marks
4
A 51-year-old taxi driver is inactive, smokes and eats a diet high in saturated fat. After an episode of severe chest pain, an angiogram shows that one coronary artery is almost completely blocked by an atheroma and a blood clot.
(a)
Describe how atherosclerosis develops and how a blood clot may then form in the affected artery.
[6 marks]
(b)
Discuss the benefits and risks of treating this man with a statin and an anticoagulant.
[6 marks]
Total for question 4: 12 marks
5
A health clinic measures the blood lipids of a 44-year-old woman. Her total cholesterol is 5.1 mmol dm⁻³, her HDL cholesterol is 1.9 mmol dm⁻³ and her LDL cholesterol is 2.6 mmol dm⁻³.
(a)
Which statement describes the role of high-density lipoproteins (HDLs)?
[1 mark]
AThey carry cholesterol from the liver to the body tissues
BThey deposit cholesterol in the walls of arteries
CThey carry cholesterol from the tissues back to the liver
DThey digest cholesterol so that it can be excreted
(b)
What percentage of the woman's total cholesterol is HDL cholesterol?
[1 mark]
A37%
B51%
C73%
D63%
(c)
Explain why a high concentration of LDL cholesterol, rather than a high concentration of HDL cholesterol, increases the risk of coronary heart disease.
[2 marks]
Total for question 5: 4 marks
6
A technician prepares a class practical in which Daphnia are placed in caffeine solutions of different concentrations. The heart beats of each Daphnia are counted through a microscope, because Daphnia are transparent.
(a)
Which statement is a valid ethical argument for using Daphnia rather than a mammal in this investigation?
[1 mark]
ADaphnia have hearts that are structurally identical to mammalian hearts
BUsing invertebrates raises no ethical issues at all
CDaphnia reproduce quickly, so no individual is ever harmed
DDaphnia are thought to have a simpler nervous system, so they are less likely to experience pain or suffering
(b)
Which variable must be kept constant so that the comparison between the caffeine concentrations is valid?
[1 mark]
AThe size of the cover slip
BThe temperature of the solutions
CThe caffeine concentration
DThe heart rate of the Daphnia
(c)
Suggest two ways in which the technician can reduce harm to the Daphnia during the practical.
[2 marks]
Total for question 6: 4 marks
7
A cohort study followed 20 000 office workers for 15 years. Coronary heart disease (CHD) developed in 3.1% of the workers who ate breakfast cereal every day and in 4.6% of the workers who did not.
(a)
A newspaper headline reads 'Breakfast cereal cuts the risk of heart disease by a third'. Evaluate whether the data support this headline.
[3 marks]
(b)
Explain how the sample of workers should be selected and why a large sample is important if the results are to be valid and reliable.
[4 marks]
Total for question 7: 7 marks
8
A 46-year-old man is 1.78 m tall and has a body mass of 98 kg. His waist measures 106 cm and his hips measure 101 cm. His energy intake averages 13 200 kJ per day and his energy expenditure averages 10 600 kJ per day. He feels healthy and believes that he is at low risk of a heart attack.
(a)
Calculate the man's body mass index (BMI) and his waist-to-hip ratio, and explain what these values and his energy figures show about his risk of CHD.
[6 marks]
(b)
Discuss why the man's perception of his risk may differ from his actual risk, and how his doctor could use scientific evidence to persuade him to reduce it.
[6 marks]
Total for question 8: 12 marks

End of questions

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).