OpenRevise

Exam questions · Biology · Respiration

Cellular Respiration and Aerobic Respiration

  • 8 exam questions
  • 21 marks
  • 8 quick checks
  1. 1 State [1 mark]

    State where most of the reactions of aerobic respiration take place in a cell.

    Show answerHide answer

    Model answer

    In the mitochondria.

    Mark scheme

    • Mitochondria (mitochondrion) — 1 mark
  2. 2 Write [2 marks]

    Write the word equation for aerobic respiration.

    Show answerHide answer

    Model answer

    glucose + oxygen → carbon dioxide + water

    Mark scheme

    • Glucose and oxygen on the left as the reactants — 1 mark
    • Carbon dioxide and water on the right as the products — 1 mark
  3. 3 Name [3 marks]

    The diagram shows a cell. Name the parts labelled A, B and C.

    A cell with arrows going in and out, with a mitochondrion marked A, the nucleus marked B and the cell membrane marked C.
    Show answerHide answer

    Model answer

    A is a mitochondrion. B is the nucleus. C is the cell membrane.

    Mark scheme

    • A: mitochondrion — 1 mark
    • B: nucleus — 1 mark
    • C: cell membrane — 1 mark
  4. 4 Explain [2 marks]

    Respiration is an exothermic reaction. Explain what this means and give one piece of evidence from living things that shows it.

    Show answerHide answer

    Model answer

    An exothermic reaction transfers energy to the surroundings. For example, the body temperature of a mammal stays warm, and a pile of germinating seeds or a compost heap becomes warmer than the air around it, because the respiring cells release heat.

    Mark scheme

    • Energy is transferred to the surroundings (as heat) — 1 mark
    • A suitable example such as a warm body, a compost heap or germinating seeds — 1 mark
  5. 5 Give [3 marks]

    Give three ways in which the energy released by respiration is used in the human body.

    Show answerHide answer

    Model answer

    Any three of: building larger molecules such as proteins from amino acids; muscle contraction for movement; keeping the body at a constant temperature; active transport of substances against a concentration gradient; cell division and growth.

    Mark scheme

    • First correct use — 1 mark
    • Second correct use — 1 mark
    • Third correct use — 1 mark
  6. 6 Explain [3 marks]

    Muscle cells contain many more mitochondria than skin cells. Explain why.

    Show answerHide answer

    Model answer

    Muscle cells need a lot of energy to contract. Most of the reactions of aerobic respiration take place in the mitochondria. Having many mitochondria means that more energy can be released every second to supply the muscle.

    Mark scheme

    • Muscle cells use a lot of energy (to contract) — 1 mark
    • Mitochondria are where aerobic respiration takes place — 1 mark
    • More mitochondria release more energy — 1 mark
  7. 7 Explain [4 marks]

    Explain how the breathing system and the circulatory system work together to supply the cells with what they need for aerobic respiration.

    Show answerHide answer

    Model answer

    Ventilation brings air into the lungs, and oxygen diffuses from the alveoli into the blood. Red blood cells carry the oxygen, and the heart pumps the blood around the body to the cells. The plasma carries glucose from digested food to the cells. The cells use the glucose and oxygen in the mitochondria, and the carbon dioxide they make diffuses into the blood and is carried back to the lungs to be breathed out.

    Mark scheme

    • Oxygen diffuses from the alveoli into the blood — 1 mark
    • Red blood cells carry oxygen, and the heart pumps the blood to the cells — 1 mark
    • Plasma carries glucose to the cells — 1 mark
    • Carbon dioxide is carried back to the lungs and breathed out — 1 mark
  8. 8 Explain [3 marks]

    A student put germinating peas in one vacuum flask and boiled peas in a second flask. Each flask had a thermometer. After two days the temperature in the flask with the germinating peas had risen by 4 degrees Celsius and the temperature in the flask with the boiled peas had not changed. Explain these results.

    Show answerHide answer

    Model answer

    The germinating peas are alive, so they respire. Respiration is exothermic and transfers energy to the surroundings as heat, so the temperature rose. The boiled peas are dead and cannot respire, so no energy was released and the temperature did not change. The boiled peas are a control that shows the warming is caused by respiration.

    Mark scheme

    • Germinating peas respire — 1 mark
    • Respiration is exothermic, so heat is released and the temperature rises — 1 mark
    • Boiled peas are dead, so there is no respiration and no temperature change — 1 mark

Quick check

  1. 1

    Which of these is the word equation for aerobic respiration?

    1. ACarbon dioxide + water → glucose + oxygen
    2. BGlucose → lactic acid
    3. CGlucose + oxygen → carbon dioxide + water
    4. DGlucose + water → carbon dioxide + oxygen
    Show answerHide answer

    C: Glucose + oxygen → carbon dioxide + water

    Aerobic respiration uses glucose and oxygen and makes carbon dioxide and water, releasing energy.

  2. 2

    What does it mean to say that respiration is an exothermic reaction?

    1. AIt takes in energy from the surroundings
    2. BIt transfers energy to the surroundings
    3. CIt needs light to take place
    4. DIt only happens when oxygen is absent
    Show answerHide answer

    B: It transfers energy to the surroundings

    An exothermic reaction transfers energy to the surroundings, often as heat.

  3. 3

    Which part of a cell contains most of the reactions of aerobic respiration?

    1. AThe nucleus
    2. BThe chloroplast
    3. CThe ribosome
    4. DThe mitochondrion
    Show answerHide answer

    D: The mitochondrion

    The mitochondria are the site of most of the reactions of aerobic respiration.

  4. 4

    How often does respiration take place in a plant cell?

    1. AAll the time, day and night
    2. BOnly in the light
    3. COnly at night
    4. DOnly when the plant is growing
    Show answerHide answer

    A: All the time, day and night

    Respiration occurs continuously in all living cells, so a plant cell respires in the dark as well as in the light.

  5. 5

    Which of these is NOT a use of the energy released by respiration?

    1. AMuscle contraction
    2. BMaking glucose from carbon dioxide
    3. CActive transport of mineral ions
    4. DKeeping a constant body temperature
    Show answerHide answer

    B: Making glucose from carbon dioxide

    Glucose is made by photosynthesis, which uses light energy. Respiration releases energy from glucose, it does not make it.

  6. 6

    Why do the cells of a root hair contain many mitochondria?

    1. AThey make glucose by photosynthesis
    2. BThey carry out anaerobic respiration only
    3. CThey use a lot of energy for active transport
    4. DThey store water in the mitochondria
    Show answerHide answer

    C: They use a lot of energy for active transport

    Root hair cells use active transport to take in mineral ions, which needs energy released by respiration in the mitochondria.

  7. 7

    What carries oxygen from the lungs to the respiring cells?

    1. ARed blood cells
    2. BWhite blood cells
    3. CPlatelets
    4. DThe alveoli
    Show answerHide answer

    A: Red blood cells

    Red blood cells contain haemoglobin, which carries oxygen from the lungs to the cells.

  8. 8

    During exercise a person breathes faster and their heart beats faster. What is the reason?

    1. AThe muscles need to make more glucose
    2. BThe body is trying to cool the lungs
    3. CThe cells have stopped respiring
    4. DThe muscle cells need more oxygen and make more carbon dioxide
    Show answerHide answer

    D: The muscle cells need more oxygen and make more carbon dioxide

    Muscle cells respire faster during exercise, so they need more oxygen and make more carbon dioxide.