OxfordAQA International GCSE Biology: Breathing and respiration (9201) – 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 sections 3.2.5 (Breathing) and 3.2.6 (Respiration) of the OxfordAQA International GCSE Biology (9201) specification, Version 5.2, for exams in May/June 2018 onwards. The qualification is untiered. Learn the content first from the study guide and the revision notes. Find other topics on the course hub and tick them off on the checklist. Also see the bioenergetics practice set and the diagnostics page.

Questions

1. Air breathed in passes down the trachea and into the alveoli.

(a) Name, in order, the two types of tube between the trachea and the alveoli. [2] (b) State where the diaphragm is found in the body. [1]

2. Explain how air is drawn into the lungs when you breathe in. [4]

3. Describe two features of alveoli that allow gases to be exchanged quickly, and say what each does. [3]

4. A patient’s spontaneous breathing has stopped after an injury, and a mechanical ventilator is used.

(a) Describe how a negative pressure ventilator helps the patient to inhale. [2] (b) Describe how a positive pressure ventilator differs. [2]

5. Aerobic respiration can be shown by a symbol equation.

(a) Complete it: C6H12O6 + ___ O2 → ___ CO2 + 6H2O [2] (b) Name the cell structures where most of the reactions of aerobic respiration take place. [1]

6. Respiration transfers energy that organisms use in different ways.

(a) Explain why a mammal in cold surroundings needs a steady rate of respiration. [1] (b) Give two ways a germinating bean seedling uses energy from respiration. [2] (c) State one use of the energy in a running animal’s leg muscles. [1]

7. A volunteer is tested at four levels of activity.

Activity	Pulse (beats per min)	Breathing rate (breaths per min)
Rest	64	14
Walking	82	18
Jogging	118	27
Sprinting	164	42

(a) Calculate the percentage increase in pulse from rest to sprinting. [2] (b) Calculate the percentage increase in breathing rate from rest to jogging. [2] (c) Explain how the changes in pulse and breathing help the leg muscles during sprinting. [2]

8. A sprinter finishes a race and continues to breathe heavily for several minutes.

(a) Explain why the sprinter’s muscles were respiring anaerobically during the race. [2] (b) Explain why heavy breathing continues after the race. [3]

9. The table shows the concentration of lactic acid in the blood of an athlete after a sprint. The athlete’s resting value is 1.1 mmol/dm3.

Time after sprint (min)	0	5	10	20	30
Lactic acid (mmol/dm3)	10.4	8.1	6.2	3.5	2.1

(a) Calculate the percentage fall in lactic acid in the first 10 minutes. [2] (b) Calculate the average rate of fall from 0 to 5 minutes. Give the unit. [2] (c) Describe how the rate of fall changes during the 30 minutes. [1] (d) At 30 minutes the value is above the resting value. Calculate by how much, and explain what this suggests. [2]

10. A student sets up two flasks of yeast in glucose solution. Each is covered with a layer of oil and connected to a gas syringe. After 10 minutes, flask A at 25 °C has collected 12 cm3 of gas and flask B at 35 °C has collected 30 cm3.

(a) Calculate the rate of gas production in each flask. [2] (b) Calculate the percentage increase in rate in flask B compared with flask A. [2] (c) Explain why the layer of oil is used. [1] (d) Name the other product, besides the gas, of anaerobic respiration in yeast. [1]

11. A sensor records the pressure inside a volunteer’s thorax compared with the air outside. A negative value means lower than the outside air.

Time (s)	0	1	2	3	4
Pressure difference (kPa)	0.0	-0.5	0.0	+0.5	0.0

(a) State the period when the volunteer is inhaling, and give the evidence from the data. [2] (b) Calculate the breathing rate in breaths per minute. [2] (c) Explain how the muscles cause the pressure change during inhalation. [3] (d) A negative pressure ventilator lowers the pressure around the chest. State whether the pressure in the chamber outside the chest is above or below atmospheric pressure when it makes the patient inhale. [1]

12. Plan an investigation into the effect of exercise on pulse rate. Include what you will change, measure and keep the same, how you will improve reliability, how you will find the recovery time and one safety precaution. [7]

Answers

1. (a) Bronchi [1] then bronchioles [1]. (b) Between the thorax and the abdomen, below the lungs [1]. [3] Examiner insight: the order matters, so writing the two names the wrong way round loses credit; do not confuse bronchi with bronchioles.

2. Intercostal muscles contract and pull the ribcage upwards [1]. The diaphragm muscles contract and the diaphragm flattens [1]. The volume of the thorax increases [1]. Pressure falls below that of the surrounding air, so air enters the lungs [1]. [4] Examiner insight: a four-mark explanation needs a chain from muscles to volume to pressure to air movement; stopping at “the lungs get bigger” leaves out the reasoning.

3. Very large surface area [1] so many gas molecules can cross at once / gases diffuse readily [1]. Richly supplied with blood capillaries [1]. [3] Examiner insight: name the feature and then say what it does; a list of features with no effect is a description, not an explanation.

4. (a) Air pressure around the chest is lowered inside a sealed chamber [1], so the chest expands and air is drawn into the lungs [1]. (b) It forces air into the lungs [1] by pushing air into the airway at a pressure higher than outside air [1]. [4] Examiner insight: say which way the pressure is changed for each type; “pushes” versus “pulls” alone is thin without a pressure comparison.

5. (a) 6 [1], 6 [1]. (b) Mitochondria [1]. [3] Examiner insight: check the equation balances by counting oxygen atoms on both sides: 6 + 12 = 18 and 12 + 6 = 18.

6. (a) Respiration transfers energy that maintains a steady body temperature [1]. (b) To build larger molecules from smaller ones [1]; to build sugars, nitrates and other nutrients into amino acids (then proteins) [1]. (c) To enable the muscles to contract [1]. [4] Examiner insight: match the use to the organism; “keeping warm” does not fit a plant, and “energy is made” is a wrong idea because energy is transferred.

7. (a) (164 - 64) / 64 x 100 [1] = 156% (156.25) [1]. (b) (27 - 14) / 14 x 100 [1] = 93% (92.86) [1]. (c) Faster heart rate means more blood flow to the muscles [1], supplying more glucose and oxygen and removing more carbon dioxide; deeper, faster breathing takes in more oxygen [1]. [6] Examiner insight: show the working so that an arithmetic slip can still earn method credit; divide by the starting value, not the final value.

8. (a) Muscles needed energy faster than oxygen could be supplied [1], so energy was transferred by anaerobic respiration [1]. (b) Lactic acid built up during the race [1]. An oxygen debt must be repaid [1] by oxidising the lactic acid to carbon dioxide and water [1]. [5] Examiner insight: “oxygen debt” alone is a label; credit comes from saying what the oxygen is used to do.

9. (a) 10.4 - 6.2 = 4.2 [1]; 4.2 / 10.4 x 100 = 40% (40.4) [1]. (b) (10.4 - 8.1) / 5 = 0.46 [1] mmol/dm3 per minute [1]. (c) The rate of fall slows over time [1]. (d) 2.1 - 1.1 = 1.0 mmol/dm3 [1]; some lactic acid is still being removed, so the oxygen debt has not been fully repaid [1]. [7] Examiner insight: units matter in a rate: mmol/dm3 per minute is the concentration unit and the time unit together.

10. (a) Flask A 12 / 10 = 1.2 cm3 per min [1]; flask B 30 / 10 = 3.0 cm3 per min [1]. (b) (3.0 - 1.2) / 1.2 x 100 [1] = 150% [1]. (c) Oil stops air (oxygen) dissolving in the mixture, so the yeast respires anaerobically [1]. (d) Ethanol [1]. [6] Examiner insight: an explanation of the oil should refer to oxygen being kept out, not to “keeping it fair”.

11. (a) 0 to 2 s [1] because the pressure is below that of the outside air, so air enters [1]. (b) One breath takes 4 s [1]; 60 / 4 = 15 breaths per minute [1]. (c) Intercostal muscles contract, pulling the ribcage up, and the diaphragm contracts and flattens [1]. The volume of the thorax increases [1]. The pressure falls below the outside air [1]. (d) Below [1]. [8] Examiner insight: a data question wants the evidence quoted, so state the sign of the pressure and say which way air moves; the period alone is not enough.

12. Change: the exercise (such as stepping on and off a step for a set time) [1]. Measure: pulse rate (for example beats counted for 15 s and multiplied by 4) [1]. Keep the same: any two of same person, step height, rate of stepping, timing of readings, room [2]. Reliability: repeat and calculate a mean [1]. Recovery time: record pulse at regular intervals after exercise until it returns to the resting value [1]. Safety: stop if anyone feels unwell / do not include people for whom exercise is unsuitable [1]. [7] Examiner insight: a plan that says “keep it a fair test” with no named variable gives the reader nothing to credit; name each control.

Where marks are usually lost

• Writing that the diaphragm moves up when inhaling.
• Explaining breathing without mentioning pressure.
• Saying the lungs “suck” or “push” air without a pressure difference.
• Confusing negative and positive pressure ventilators.
• Mixing up breathing and respiration.
• Saying energy is “made” in mitochondria.
• Dividing by the new value in a percentage change.
• Leaving out units for rates.
• Giving lactic acid for yeast, or ethanol for muscle.
• Describing oxygen debt without saying lactic acid is oxidised.

Next steps

• Re-read the revision notes for any weak areas.
• Review the study guide.
• Back to the course hub and the checklist.
• Take the free 10-minute diagnostics.
• Book a free trial class.

Official syllabus

OxfordAQA International GCSE Biology (9201), Version 5.2, for exams in May/June 2018 onwards, published by OxfordAQA. Sections 3.2.5 and 3.2.6.