Importance of ATP (1.1): Eduqas A Level Biology Exam Questions by Topic

EduqasImportance of ATPExam Questions
Written by Tom Whitburn

Importance of ATP is the first topic of Component 1, Energy for Life, and it sets up both photosynthesis and respiration. You need chemiosmosis: how electron transport chains drive proton pumps, how a proton gradient builds up across the inner mitochondrial membrane or the thylakoid membrane, and how protons flowing back through ATP synthetase make ATP. Every question on this page is from the A level Component 1 papers.

These questions are short, and most students do well on them. The marks usually go to the direction of proton flow (from the intermembrane space into the matrix), the name of the enzyme (ATP synthetase, not ATPase), and what happens when a membrane becomes leaky to protons: the gradient is lost, less ATP is made and the energy is released as heat.

I don't teach the Eduqas specification myself, so for one-to-one help I recommend Sam. He teaches Eduqas A level Biology at a top-rated sixth form college and is very popular with his students. You can ask about lessons with Sam on WhatsApp using the link at the bottom of this page.

What you need from GCSE and Year 12

Each question on this page assumes you're secure on these ideas. If any of them feels shaky, look it up before you start.

  • ATP is made from ADP and inorganic phosphate (Pi) and releases energy when it is hydrolysed.
  • Mitochondria have an inner membrane folded into cristae; chloroplasts have thylakoid membranes.
  • Electrons can carry energy; oxidation is loss of electrons or hydrogen and reduction is gain.
  • Diffusion is net movement down a concentration gradient.

Key terms

These words come up in the questions and mark schemes. Examiners expect you to use them exactly.

  • Chemiosmosis: making ATP using the energy of protons flowing down their gradient through ATP synthetase.
  • Proton pump: a membrane carrier protein that uses energy from electrons to move H⁺ against its gradient.
  • Electron transport chain: a series of electron carriers and proton pumps in a membrane.
  • Proton gradient: a higher concentration of H⁺ on one side of a membrane, a store of potential energy.
  • ATP synthetase: the enzyme in the stalked particles that joins ADP and Pi as protons flow through it.
  • Intermembrane space: the gap between the outer and inner mitochondrial membranes, where protons build up.
  • Final electron acceptor: oxygen, which takes electrons at the end of the chain in aerobic respiration.

What these questions cover (Eduqas 1.1)

The questions test these statements from Component 1 (Energy for Life) of the Eduqas A level Biology specification (A400). Component 1 content is examined in A level Component 1.

  • (a) the synthesis of ATP involving a flow of protons through the enzyme ATP synthetase, the process of chemiosmosis and the electrochemical gradient
  • (b) the similarity between mitochondrial and chloroplast membrane function in providing a proton gradient for ATP synthesis
  • (c) the proton gradient
  • (d) the electron transport chain is formed from an alternate arrangement of pumps and electron carriers (names of proton pumps and electron carriers in the electron transport

How to use this page

Write your answer on paper before you open the mark scheme. Allow about 1.2 minutes per mark: the 14 questions are worth 34 marks, so about 41 minutes in total. Then mark your answer strictly against the mark scheme and read the examiners' tip underneath it. If you'd rather print the questions, download the PDF pack.

Chemiosmosis

Question 1

A level Component 1 · Autumn 2020 · Q3(b)(ii) · 3 marks

Outline the process of chemiosmosis in an animal cell.

Exam question: outline the process of chemiosmosis in an animal cell.
Show the mark scheme Mark scheme: Any three (×1) from H+ flow from intermembrane space to matrix (1) through stalked particle/ protein channels (1) Energy provided to ATP synthase (1) ADP + Pi = ATP (1)

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From the examiners' report: Understanding was very good and most students scored all three marks: H⁺ flows from the intermembrane space to the matrix, through ATP synthase, giving energy to join ADP and Pi.

Question 2

A level Component 1 · June 2017 · Q6(a) · 2 marks

Describe the route protons normally take to make ATP.

Exam question: Following the establishment of an electrochemical gradient, describe the normal route that the protons would take in order to synthesise ATP.
Show the mark scheme Mark scheme: From the intermembrane space into the matrix (1) Via (a stalked particle containing) ATP synthase (1)

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From the examiners' report: Well done by most: from the intermembrane space into the matrix, through the stalked particle containing ATP synthase.

Question 3

A level Component 1 · June 2025 · Q1(a)(ii) · 3 marks

Describe the role of hydrogen ions in ATP synthesis.

Exam question: Describe the role of hydrogen ions in ATP synthesis.
Show the mark scheme Mark scheme: Any three (x1) from • protons {flow / move / diffuse / travel} down a (concentration / electrochemical / owtte) gradient (1) • from inter-membrane space to matrix (1) • through ATP {synthetase / synthase} (1) • provide energy for {ADP + Pi → ATP / description of} (1)

Tap an image to open it full size.

Question 4

A level Component 1 · Autumn 2020 · Q3(d)(i) · 2 marks

Explain how capsaicin, which makes the membrane leaky to protons, reduces ATP production.

Exam question: Explain how capsaicin reduces ATP production by BAT cells.
Show the mark scheme Mark scheme: less proton gradient (1) therefore there are less protons to ATP synthetase so produce less ATP (1)

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From the examiners' report: Most students got this: a smaller proton gradient means fewer protons flow through ATP synthetase.

Question 5

A level Component 1 · June 2022 · Q2(b)(i) · 3 marks

Explain how a membrane leaky to protons lets a flower generate heat.

Exam question: The inner membranes of mitochondria in some cells of the flowers are permeable to protons. Using your knowledge of respiration in mitochondria, explain how this enables the flower to generate heat.
Show the mark scheme Mark scheme: Any three (x1) from: A. no proton gradient produced (1) B. {Less/no} Protons flow through {stalked particles/ ATP synthetase} (1) C. {Less/No ATP} produced (via ATP synthase) therefore any energy released is lost as heat. (1) D. So increased respiration rate (1)

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From the examiners' report: Stronger students explained it. Many wrongly thought it would increase ATP production, with the ATP then used to make heat: no gradient means little ATP, so the energy is lost as heat.

Proton gradients

Question 6

A level Component 1 · June 2023 · Q1(a)(i)I · 1 mark

Name the general term for a protein that moves protons across the membrane.

Exam question: Name the following: I. the general term for the protein labelled C.
Show the mark scheme Mark scheme: Proton pump / carrier protein (1) Reject channel protein

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Question 7

A level Component 1 · June 2023 · Q1(a)(i)II · 1 mark

Name the enzyme in the protein complex that makes ATP.

Exam question: II. the enzyme found in protein complex D.
Show the mark scheme Mark scheme: ATP synthetase / synthase (1) Reject ATPase

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Mitochondria and chloroplasts

Question 8

A level Component 1 · June 2023 · Q1(b)(i) · 2 marks

Identify where the structures in the diagram are found in mitochondria and chloroplasts.

Exam question: Name the two organelles in which structure D is found in eukaryotic cells and state precisely where it would be located in each of these organelles.
Show the mark scheme Mark scheme: Mitochondria + inner membrane (1) Ignore cristae Chloroplasts + thylakoid membrane (1) Ignore chlorophyll

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From the examiners' report: The report asks you to make sure you can compare ATP synthesis in mitochondria and chloroplasts correctly: the inner mitochondrial membrane and the thylakoid membrane.

Question 9

A level Component 1 · June 2024 · Q1(b)(iii) · 2 marks

Complete a table showing where protons are pumped and where they build up.

Exam question: Complete the table below to identify where in chloroplasts and mitochondria the following processes in ATP synthesis take place.
Show the mark scheme Mark scheme: Process in ATP Chloroplasts Mitochondria synthesis Protons are thylakoid inner (mitochondrial) pumped… (membrane) (membrane) / cristae thylakoid A high inter-membrane space space / lumen concentration Reject inner / intra Ignore inter All 4 correct = 2 marks; 3 or 2 correct = 1 mark;

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From the examiners' report: Many students couldn't compare the structure of chloroplasts and mitochondria correctly. Protons build up in the thylakoid space and in the intermembrane space.

Question 10

A level Component 1 · June 2018 · Q1(c) · 4 marks

State four similarities between ATP synthesis in chloroplasts and a bacterium.

Exam question: A simple diagram showing ATP synthesis in a chloroplast and a Gram negative bacterium is shown below. Chloroplast Bacterium (E. coli) Thylakoid Intermembrane lumen space (periplasm) H+ H+ ATP Stroma Cytosol ATP State four similarities between the process of ATP synthesis in chlor
Show the mark scheme Mark scheme: Any four (x1) from: 1. Both involve proton pumps/ protons are pumped(1) 2. {Driven/ powered} by {electron (energy)/ redox reactions of ETC}(1) 3. Creation of {electro chemical/ proton/ chemiosmotic} gradient (1) 4. {Diffusion/ flow} of {hydrogen ions/ protons}/ protons {travel down/ pass through} {stalked particle/ car

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The electron transport chain

Question 11

A level Component 1 · Autumn 2021 · Q4(b)(ii) · 1 mark

Name the series of molecules that electrons pass along in the membrane.

Exam question: The electrons are passed along a series of molecules in the membrane. State the name given to this series of molecules. 
Show the mark scheme Mark scheme: electron transport {chain/ system} Accept electron carriers

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Question 12

A level Component 1 · Autumn 2021 · Q4(b)(iii) · 3 marks

Describe how the energy released by the moving electrons is used.

Information from earlier in this question:

Earlier part of the same exam question, giving the information this part uses. Exam question: Describe how the energy released from the movement of these electrons is used. 
Show the mark scheme Mark scheme: Any three (×1) from: Pumping protons (1) against concentration gradient (1) from cytoplasm into (bacterial) cell wall (1) creating proton gradient (1)

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From the examiners' report: Students had a very good understanding of ATP synthesis here: the energy pumps protons against their gradient, building up a proton gradient.

Question 13

A level Component 1 · Autumn 2021 · Q4(b)(iv) · 3 marks

Describe how ADP is then phosphorylated.

Exam question: Describe how ADP is phosphorylated as a result of the reaction shown in image 4.1.
Show the mark scheme Mark scheme: Protons flow down concentration gradient (1) Through {stalked particle/ ATP synthase/ ATP synthetase} (1) Provide energy to join ADP and Pi (1)

Tap an image to open it full size.

Question 14

A level Component 1 · Autumn 2021 · Q6(a)(i) · 4 marks

Explain how cyanide prevents aerobic respiration.

Exam question: (i) With reference to image 6.1 explain how cyanide would prevent the process of aerobic respiration.
Show the mark scheme Mark scheme: Any four (×1) from: A. ATP synthesis via electron transport chain stops (1) B. Because cyanide stops transfer of an electron to final electron acceptor (1) C. Electrons cannot be accepted by electron carriers / cytochromes along ETC (1) D. Flow of electrons stops (1) E. Electron donors NADH2 and FADH2 cannot be oxidise

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From the examiners' report: There were some excellent answers: electrons can't pass to the final acceptor, so the flow of electrons stops and NADH and FADH₂ can't be oxidised.

Where students lose marks (from Eduqas examiners' reports and mark schemes)

Each point below is followed by wording that gained marks.

  • Leaky membrane means less ATP, not more: Many students thought a membrane permeable to protons would increase ATP production, which was then used to make heat.

    ✔ Gains credit: "No proton gradient produced" so "less / no ATP produced" and "energy released is lost as heat".

  • Compare the right membranes: Students couldn't compare ATP synthesis in mitochondria and chloroplasts correctly.

    ✔ Gains credit: "Mitochondria + inner membrane" and "Chloroplasts + thylakoid membrane".

  • Intermembrane space, not inner: Many students couldn't compare the structure of chloroplasts and mitochondria.

    ✔ Gains credit: Protons build up in the "thylakoid space / lumen" and the "inter-membrane space" (inner and intra are rejected).

  • ATP synthetase, not ATPase: The mark scheme rejects ATPase for the enzyme that makes ATP.

    ✔ Gains credit: "ATP synthetase / synthase" (Reject ATPase).

  • A pump, not a channel: The mark scheme rejects channel protein for the protein that moves protons against their gradient.

    ✔ Gains credit: "Proton pump / carrier protein" (Reject channel protein).

Download the questions

Download the PDF pack (14 questions, mark schemes at the end)

Keep practising

Questions, mark schemes and examiners' report extracts © WJEC CBAC Ltd (Eduqas).

Tom Whitburn
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