AQA GCSE Biology 8461: Principles of organisation; the heart and blood vessels – Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – examination boards hold copyright in their own papers. Use these alongside the official past papers from your board or school.

These questions cover 4.2.1 Principles of organisation and 4.2.2.2 The heart and blood vessels of the AQA GCSE Biology (8461) specification, for teaching from September 2016 and exams from 2018 onwards. Both are assessed on Paper 1, set at Foundation and Higher Tier. Neither subtopic has content marked (HT only), so every question suits both tiers. Questions 2, 9 and 10 practise the size-and-scale and blood-flow rate skills (MS 1a, 1c).

Learn the content first in the study guide for this unit and the revision notes for this unit. Questions on digestion (4.2.2.1) are in the separate Enzymes and the Digestive System practice questions. The course hub is AQA GCSE Biology, and the printable checklist lists every point.

Questions

1.

(a) State what is meant by a tissue. [1] (b) Explain why a lung is described as an organ. [2]

2. An alveolus has a diameter of 0.24 mm. A red blood cell has a diameter of 8 µm.

(a) Convert 0.24 mm into micrometres. [1] (b) Calculate how many red blood cells would fit side by side across the alveolus. [1]

3. Name:

(a) the chamber of the heart that receives blood from the pulmonary vein [1] (b) the blood vessel that carries blood out of the right ventricle [1] (c) the blood vessels that supply the heart muscle with oxygenated blood. [1]

4. Explain why the wall of the left ventricle is thicker than the wall of the right ventricle. [2]

5.

(a) Describe what is meant by a double circulatory system. [2] (b) An oxygen molecule diffuses from an alveolus into the blood. Describe the route it takes to reach a muscle cell in the leg. Name the blood vessels and heart chambers it passes through. [4]

6.

(a) State where the group of cells that controls the natural resting heart rate is found. [1] (b) A patient’s heart beats irregularly. Explain how an artificial pacemaker can help. [2]

7. Explain how the lungs are adapted for efficient gaseous exchange. [6]

8. A student measured three blood vessels, A, B and C, from prepared slides.

Vessel	Wall thickness (mm)	Lumen diameter (mm)
A	1.0	4.0
B	0.5	5.0
C	0.001	0.008

(a) Calculate the ratio of wall thickness to lumen diameter for vessel A and for vessel B. [2] (b) Use your answers to identify which of A and B is the artery and which is the vein. Give a reason. [2] (c) Vessel C is a capillary. Explain how its structure relates to its function. [2]

9. A student investigates her heart rate.

(a) At rest she counts 32 pulse beats in 30 seconds. Calculate her heart rate in beats per minute. [2] (b) At rest her heart pumps 75 cm³ of blood per beat. Calculate the volume pumped per minute. Give your answer in dm³. [2] (c) During exercise her heart rate is 150 beats per minute and her heart pumps 110 cm³ per beat. Calculate the percentage increase in volume pumped per minute compared with rest. Give your answer to the nearest whole number. [3]

10.

(a) 0.9 dm³ of blood flows through an artery in 12 seconds. Calculate the rate of blood flow in cm³ per second. [2] (b) In a capillary, a red blood cell moves 1.2 mm in 3 seconds. The capillary is 0.8 mm long. Calculate how long the cell takes to travel the full length of the capillary. [2] (c) Suggest why slow blood flow in capillaries is an advantage. [1]

11. Use the terms cell, tissue, organ and organ system to explain how the body is organised to deliver oxygen to a muscle cell in the arm. [5]

12.

(a) Explain why veins have valves. [2] (b) Explain why the walls of arteries contain thick layers of muscle and elastic fibres. [2]

Answers

1. (a) A group of cells with a similar structure and function [1] (b) It is made of several different tissues [1] working together to perform a specific function (gas exchange) [1] Examiner insight: “A group of tissues” alone earns one mark; the second mark needs the idea of a specific function, such as gas exchange.

2. (a) 0.24 x 1000 = 240 µm [1] (b) 240 / 8 = 30 red blood cells [1] Examiner insight: An answer of 0.03 shows the units were not converted first, and earns no credit even though the division was right.

3. (a) Left atrium [1] (b) Pulmonary artery [1] (c) Coronary arteries [1] Examiner insight: In (a) the side must be named, so “atrium” alone scores zero; in (b) “pulmonary vein” or a bare “artery” scores zero.

4. The left ventricle pumps blood around the whole body [1]; the right ventricle pumps blood only to the lungs, so the left side needs more muscle to pump at higher pressure [1] Examiner insight: “Because it pumps harder” is too vague for credit; link the thicker wall to the greater distance (whole body) or higher pressure.

5. (a) Blood passes through the heart twice in one complete circuit of the body [1]; one circuit goes from the right ventricle to the lungs and the other from the left ventricle to the rest of the body [1] (b) Pulmonary vein [1] to the left atrium [1], then the left ventricle [1], then out through the aorta (to arteries, then capillaries in the leg muscle) [1] Examiner insight: The route mark is lost if the order is wrong, for example aorta before left ventricle, even when every name is correct.

6. (a) In the right atrium [1] (b) An artificial pacemaker is an electrical device [1] that corrects the irregular heart rate, keeping it beating at a regular rate [1] Examiner insight: “It controls the heart” earns nothing on its own; the mark needs the idea of correcting irregularity or setting a regular rate.

7. Any six points, up to three features with their effect: There are millions of alveoli [1], giving a large surface area for diffusion [1] The walls of the alveoli are very thin [1], so the diffusion distance between air and blood is short [1] Each alveolus is surrounded by a network of capillaries [1]; the blood flow carries oxygen away and brings carbon dioxide, keeping a steep concentration gradient [1] Examiner insight: On a six-mark explain question, a list of features with no effects caps the answer at about half marks; pair each feature with its effect on diffusion.

8. (a) A: 1.0 / 4.0 = 0.25 [1]; B: 0.5 / 5.0 = 0.1 [1] (b) A is the artery and B is the vein [1]; A has a thicker wall relative to its lumen, to withstand high pressure, while B has a wider lumen and thinner wall because blood pressure in veins is low [1] (c) The wall is only one cell thick [1], so the diffusion distance is short and substances such as oxygen and glucose diffuse quickly between the blood and body cells [1] Examiner insight: In (b), allow error carried forward from (a); a correct identification with no reason scores only the first mark.

9. (a) 32 / 30 x 60 [1] = 64 beats per minute [1] (b) 64 x 75 = 4800 cm³ per minute [1]; 4800 / 1000 = 4.8 dm³ per minute [1] (c) Exercise: 150 x 110 = 16 500 cm³ per minute [1]; increase = 16 500 - 4800 = 11 700 cm³ [1]; 11 700 / 4800 x 100 = 244% [1] Examiner insight: In (c), dividing the increase by the exercise value instead of the resting value is a common slip that loses the final mark; allow ECF from (a) and (b).

10. (a) 0.9 dm³ = 900 cm³; 900 / 12 [1] = 75 cm³ per second [1] (b) Speed = 1.2 / 3 = 0.4 mm per second [1]; time = 0.8 / 0.4 = 2 seconds [1] (c) It gives more time for substances to diffuse between the blood and the body cells [1] Examiner insight: In (a), an answer of 0.075 shows the dm³ to cm³ conversion was missed and loses the accuracy mark; the unit must match the one asked for.

11. Cells, such as muscle cells or cells lining the alveoli, are the basic building blocks [1] Similar cells group together to form tissues, such as muscle tissue in the heart wall [1] Different tissues make up organs, such as the heart and the lungs [1] The heart, blood vessels and blood form the circulatory system, an organ system; the lungs are part of the respiratory system [1] The organ systems work together: the lungs load oxygen into the blood and the heart pumps it through arteries to capillaries next to the muscle cell [1] Examiner insight: Each term must be used correctly with an example; calling the heart a tissue or the lungs an organ system loses that point.

12. (a) Blood in veins is at low pressure [1], so valves are needed to stop blood flowing backwards [1] (b) Blood leaves the heart at high pressure; the thick muscle withstands this pressure [1]; the elastic fibres let the wall stretch with each surge of blood and then recoil [1] Examiner insight: Two separate ideas are needed for each two-mark part; repeating “high pressure” twice in (b) earns only one mark.

Where marks are usually lost

• Naming a chamber or vessel without its side (left/right) or its full name (pulmonary artery, not “artery”).
• Putting the steps of the blood route in the wrong order.
• Saying the left ventricle is thicker “to pump harder” with no link to the whole body or higher pressure.
• Placing the natural pacemaker anywhere other than the right atrium.
• Listing lung features without stating the effect on diffusion.
• Writing “thin wall” for capillaries instead of “one cell thick” plus “short diffusion distance”.
• Forgetting to convert units (mm to µm, dm³ to cm³) before dividing.
• Calculating a percentage increase using the new value as the denominator.
• Using cell, tissue and organ loosely, for example calling the heart a tissue.

Next steps

• Revision notes for this unit
• Study guide for this unit
• Enzymes and the Digestive System study guide
• AQA GCSE Biology course hub
• Printable AQA GCSE Biology checklist
• All free 10-minute diagnostics
• Book a free trial class

Official syllabus

AQA GCSE Biology (8461) specification, Version 1.0, for teaching from September 2016 and exams from 2018 onwards (AQA), section 4.2 Organisation: 4.2.1 Principles of organisation and 4.2.2.2 The heart and blood vessels.