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Exam questions · Biology · Homeostasis

Glucagon and Blood Glucose (Higher tier)

  • 6 exam questions
  • 19 marks
  • 9 quick checks
  1. 1 State [1 mark]

    State the name of the hormone that increases the blood glucose concentration.

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    Model answer

    Glucagon.

    Mark scheme

    • Glucagon — 1 mark
  2. 2 Describe [2 marks]

    Describe what glucagon does in the liver.

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    Model answer

    Glucagon makes the liver convert glycogen into glucose, and the glucose is released into the blood.

    Mark scheme

    • Glycogen converted to glucose — 1 mark
    • Glucose released into the blood — 1 mark
  3. 3 Explain [3 marks]

    Explain why glucagon is released from the pancreas during a long period of exercise.

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    Model answer

    Muscle cells use glucose in respiration, so the blood glucose concentration falls. The cells of the pancreas detect the fall, and release glucagon. Glucagon makes the liver release glucose, so the concentration rises back to normal.

    Mark scheme

    • Glucose is used in respiration, so it falls — 1 mark
    • Pancreas releases glucagon — 1 mark
    • Liver releases glucose — 1 mark
  4. 4 Explain [3 marks]

    Explain why insulin and glucagon are described as having opposite effects.

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    Model answer

    Insulin is released when the blood glucose is too high, and it lowers the concentration, by making the cells take up glucose and the liver store it as glycogen. Glucagon is released when the glucose is too low, and raises the concentration, by making the liver release glucose.

    Mark scheme

    • Insulin lowers the blood glucose — 1 mark
    • Glucagon raises the blood glucose — 1 mark
    • Released at opposite times — 1 mark
  5. 5 Describe [4 marks]

    Describe how the blood glucose concentration of a healthy person changes over a day, and explain the changes.

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    Model answer

    The concentration rises after each meal, because glucose is absorbed from the digested food, and insulin is then released, which makes the concentration fall. Between meals the concentration falls slightly, below normal, and glucagon is released, which makes the liver release glucose, so the concentration returns to about 5 mmol per dm³.

    Mark scheme

    • Rises after meals — 1 mark
    • Insulin makes it fall — 1 mark
    • Falls between meals — 1 mark
    • Glucagon makes it rise back to normal — 1 mark
  6. 6 Evaluate [6 marks]

    Explain how negative feedback controls the concentration of glucose in the blood, using insulin and glucagon.

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    Model answer

    If the blood glucose concentration rises, for example after a meal, the pancreas detects it and releases insulin. Insulin makes cells take up glucose, and the liver converts it to glycogen, so the concentration falls back to normal. If the concentration falls too low, for example between meals, the pancreas releases glucagon instead. Glucagon makes the liver convert glycogen to glucose, and release it into the blood, so the concentration rises back to normal. In each case the response reverses the original change, which is negative feedback, and when the concentration is normal, less of each hormone is released.

    Mark scheme

    • Rise detected, insulin released — 1 mark
    • Cells take up glucose, liver stores glycogen — 1 mark
    • Fall detected, glucagon released — 1 mark
    • Liver converts glycogen to glucose — 1 mark
    • Each response reverses the change — 1 mark
    • Less hormone released at normal level — 1 mark

Quick check

  1. 1

    Which hormone raises the blood glucose concentration?

    1. AInsulin
    2. BAdrenaline
    3. COestrogen
    4. DGlucagon
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    D: Glucagon

    Glucagon.

  2. 2

    Where does glucagon act?

    1. AOn the liver
    2. BOn the stomach
    3. COn the lungs
    4. DOn the skin
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    A: On the liver

    On the liver.

  3. 3

    What does glucagon make the liver do?

    1. AConvert glucose to glycogen
    2. BMake insulin
    3. CConvert glycogen to glucose
    4. DDigest protein
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    C: Convert glycogen to glucose

    Convert glycogen to glucose.

  4. 4

    When is glucagon released?

    1. AWhen the blood glucose is too high
    2. BWhen the blood glucose is too low
    3. CWhen the body is too hot
    4. DWhen the water content is too high
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    B: When the blood glucose is too low

    When the blood glucose is too low.

  5. 5

    Which organ makes both insulin and glucagon?

    1. AThe pancreas
    2. BThe liver
    3. CThe kidney
    4. DThe thyroid
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    A: The pancreas

    The pancreas.

  6. 6

    Why do insulin and glucagon have opposite effects?

    1. ABoth lower the blood glucose
    2. BOne is a protein and one is a lipid
    3. CThey are made in different organs
    4. DOne lowers and the other raises the blood glucose
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    D: One lowers and the other raises the blood glucose

    One lowers and the other raises the blood glucose concentration.

  7. 7

    What happens to the blood glucose during exercise?

    1. AIt always rises
    2. BIt stays exactly the same
    3. CIt tends to fall
    4. DIt is converted to protein
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    C: It tends to fall

    It tends to fall, because muscle cells use glucose in respiration.

  8. 8

    What is the storage molecule in the liver?

    1. AGlucagon
    2. BGlycogen
    3. CInsulin
    4. DGlucose
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    B: Glycogen

    Glycogen.

  9. 9

    What type of control keeps the blood glucose steady?

    1. ANegative feedback
    2. BPositive feedback
    3. CNo feedback
    4. DDiffusion
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    A: Negative feedback

    Negative feedback.