OpenRevise

Exam questions · Biology · Homeostasis

Insulin and Blood Glucose

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

    State the name of the organ that releases insulin.

    Show answerHide answer

    Model answer

    The pancreas.

    Mark scheme

    • Pancreas — 1 mark
  2. 2 Name [2 marks]

    Name the hormone that lowers the blood glucose concentration, and the storage carbohydrate that the liver makes from glucose.

    Show answerHide answer

    Model answer

    Insulin, and glycogen.

    Mark scheme

    • Insulin — 1 mark
    • Glycogen — 1 mark
  3. 3 Describe [3 marks]

    Describe how the blood glucose concentration changes after a person eats a meal, and what the body does in response.

    Show answerHide answer

    Model answer

    The blood glucose concentration rises after the meal. The pancreas releases insulin, which makes the cells take up glucose, so the blood glucose concentration falls back to normal.

    Mark scheme

    • Concentration rises — 1 mark
    • Pancreas releases insulin — 1 mark
    • Cells take up glucose, so the level falls — 1 mark
  4. 4 Explain [3 marks]

    Explain why the control of the blood glucose concentration is an example of negative feedback.

    Show answerHide answer

    Model answer

    When the glucose concentration rises, insulin is released, which makes it fall. When it has returned to normal, less insulin is released. The response reverses the change.

    Mark scheme

    • Rise triggers insulin — 1 mark
    • Insulin makes the concentration fall — 1 mark
    • The response reverses the change — 1 mark
  5. 5 Calculate [2 marks]

    A person's blood glucose concentration rises to 9.0 mmol per dm³ after a meal. After 3 hours it has fallen to 5.4 mmol per dm³. Calculate the mean rate of fall in mmol per dm³ per hour.

    Show answerHide answer

    Model answer

    The fall is 3.6 mmol per dm³, and 3.6 divided by 3 is 1.2 mmol per dm³ per hour.

    Mark scheme

    • 9.0 minus 5.4 is 3.6 — 1 mark
    • 1.2 mmol per dm³ per hour — 1 mark
  6. 6 Evaluate [6 marks]

    Explain how insulin controls the concentration of glucose in the blood, and why this control is important.

    Show answerHide answer

    Model answer

    After a meal, carbohydrate is digested to glucose, which is absorbed into the blood, so the blood glucose concentration rises. The pancreas detects the rise, and releases insulin into the blood. Insulin is carried to the liver and the muscles, where it makes the cells take up glucose from the blood. The liver converts the glucose into glycogen, which is stored. The blood glucose concentration falls to its normal level, and the pancreas then releases less insulin, which is negative feedback. This control is important because the cells need a steady supply of glucose for respiration, and if the concentration were too high, water would leave cells by osmosis, and tissues would be damaged.

    Mark scheme

    • Glucose concentration rises after a meal — 1 mark
    • Pancreas detects it and releases insulin — 1 mark
    • Cells take up glucose — 1 mark
    • Liver converts glucose to glycogen — 1 mark
    • Negative feedback, less insulin when normal — 1 mark
    • Cells need steady glucose, or osmosis damage — 1 mark

Quick check

  1. 1

    Which organ releases insulin?

    1. AThe liver
    2. BThe kidney
    3. CThe pancreas
    4. DThe stomach
    Show answerHide answer

    C: The pancreas

    The pancreas.

  2. 2

    What does insulin do?

    1. ARaises the blood glucose
    2. BLowers the blood glucose
    3. CDigests food
    4. DMakes glucose
    Show answerHide answer

    B: Lowers the blood glucose

    It makes cells take up glucose, lowering the blood glucose concentration.

  3. 3

    What does the liver convert glucose into?

    1. AStarch
    2. BProtein
    3. CFat
    4. DGlycogen
    Show answerHide answer

    D: Glycogen

    Glycogen.

  4. 4

    What is the normal blood glucose concentration?

    1. AAbout 5 mmol per dm³
    2. BAbout 50 mmol per dm³
    3. CAbout 0.5 mmol per dm³
    4. DAbout 500 mmol per dm³
    Show answerHide answer

    A: About 5 mmol per dm³

    About 5 mmol per dm³.

  5. 5

    What happens to the release of insulin when the blood glucose falls to normal?

    1. AMore insulin is released
    2. BIt stays the same
    3. CLess insulin is released
    4. DIt is destroyed
    Show answerHide answer

    C: Less insulin is released

    Less insulin is released, which is negative feedback.

  6. 6

    What detects a rise in the blood glucose?

    1. ACells in the liver
    2. BCells in the pancreas
    3. CCells in the skin
    4. DCells in the brain
    Show answerHide answer

    B: Cells in the pancreas

    Cells in the pancreas.

  7. 7

    Why does the blood glucose rise after a meal?

    1. ACarbohydrate is digested to glucose, which is absorbed
    2. BThe liver releases insulin
    3. CCells make glucose
    4. DWater is lost
    Show answerHide answer

    A: Carbohydrate is digested to glucose, which is absorbed

    Carbohydrate is digested to glucose, which is absorbed.

  8. 8

    What is the storage carbohydrate in the liver?

    1. ACellulose
    2. BStarch
    3. CLipid
    4. DGlycogen
    Show answerHide answer

    D: Glycogen

    Glycogen.

  9. 9

    Which statement about insulin is correct?

    1. AIt is carried in the nerves
    2. BIt is a hormone carried in the blood
    3. CIt is a digestive enzyme
    4. DIt is made in the liver
    Show answerHide answer

    B: It is a hormone carried in the blood

    It is a hormone carried in the blood.