Lesson 3.6.4.2.1

3.6.4.2.1 Insulin, glucagon and the liver Quiz: AQA Biology, Unit 6

20 questions

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Lesson 3.6.4.2.1, Insulin, glucagon and the liver: 20 multiple choice questions for the AQA Biology (7402), Unit 6: Organisms respond to changes in their internal and external environments, written with Revision Ninja.

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The 20 questions

  1. Which cells in the pancreas secrete insulin?

    • Hepatocytes in the lobules of the liver
    • Beta cells in the islets of Langerhans
    • Acinar cells lining the pancreatic ducts
    • Alpha cells in the islets of Langerhans
  2. Which process converts stored glycogen back into glucose in liver cells?

    • Gluconeogenesis
    • Glycogenesis
    • Lipogenesis
    • Glycogenolysis
  3. What is the effect of insulin on blood glucose concentration?

    • It lowers blood glucose by stopping glycogen storage in the liver
    • It lowers blood glucose by increasing glucose uptake into cells and glycogen storage
    • It raises blood glucose by increasing glycogen breakdown in the liver
    • It raises blood glucose by reducing glucose uptake into target cells
  4. Glucagon raises blood glucose concentration mainly through which action in liver cells?

    • Blocking the uptake of glycerol and amino acids into liver cells
    • Activating enzymes that convert glycogen into glucose
    • Activating enzymes that convert glucose into glycogen
    • Inserting extra glucose channel proteins into the cell surface membrane
  5. Gluconeogenesis in the liver is best defined as:

    • Breakdown of glycogen into glucose molecules for release into the blood
    • Synthesis of glucose from non-carbohydrate sources such as glycerol and amino acids
    • Breakdown of fatty acids into acetyl coenzyme A for respiration
    • Synthesis of glycogen from glucose molecules stored in the liver
  6. How does insulin increase the rate of glucose uptake into target cells?

    • By converting glucose directly into amino acids in the cytoplasm
    • By breaking down glucose inside the cell surface membrane
    • By binding glucose molecules and carrying them into the nucleus
    • By regulating the inclusion of channel proteins in the cell surface membrane
  7. Where do insulin and glucagon bind on target cells?

    • To enzymes free in the cytoplasm of target cells
    • To receptors inside the nucleus of target cells
    • To carrier proteins in the membranes of red blood cells only
    • To receptors on the surface membranes of target cells
  8. A person has just eaten a meal and blood glucose rises to 9.0 mmol per dm3. Which response is expected?

    • Insulin secretion falls and glycogen is broken down in the liver
    • Glucagon secretion rises and muscle cells release glucose into the blood
    • Insulin secretion rises and the liver converts more glucose into glycogen
    • Glucagon secretion rises and the liver releases more glucose into the blood
  9. During a prolonged fast, which combination of hormone and liver activity is most likely?

    • High insulin with increased glycogenolysis and reduced glucose uptake
    • High insulin with increased glycogenesis and glucose uptake by liver cells
    • High glucagon with increased glycogenolysis and gluconeogenesis
    • High glucagon with reduced glycogenolysis and increased glycogenesis
  10. Adrenaline raises blood glucose in a way similar to glucagon. Which action do they share in liver cells?

    • Both stop the conversion of glycerol into glucose
    • Both activate enzymes that convert glucose into glycogen
    • Both block the attachment of glycogen to the cell surface membrane
    • Both activate enzymes that convert glycogen into glucose
  11. A patient's beta cells are destroyed. Which effect is most likely after a carbohydrate meal?

    • Blood glucose falls quickly because glucagon is no longer secreted
    • Blood glucose falls quickly because insulin is converted into glycogen
    • Blood glucose stays low because glycogenolysis is increased
    • Blood glucose stays high for longer because uptake and glycogen storage are reduced
  12. In a colorimetric calibration curve of absorbance against glucose concentration, how is the concentration of an unknown sample found?

    • Multiply its absorbance by the highest standard concentration used
    • Compare its colour only with the first standard and report that value
    • Read across from its absorbance to the curve and then down to the concentration axis
    • Average its absorbance with that of the standards and report the mean
  13. Blood glucose is 10.0 mmol per dm3 and falls by 20 per cent after insulin acts. What is the new concentration?

    • 8.0 mmol per dm3
    • 2.0 mmol per dm3
    • 12.0 mmol per dm3
    • 7.0 mmol per dm3
  14. A drug blocks glucagon receptors on liver cells. What is the most likely effect during an overnight fast?

    • Blood glucose is unchanged because glucagon does not act on liver cells
    • Blood glucose rises because insulin can no longer bind to liver cells
    • Blood glucose rises because glycogen is converted into fat in the liver
    • Blood glucose falls more than normal because glycogenolysis and gluconeogenesis are reduced
  15. Which statement correctly describes glucose homeostasis by the liver?

    • The liver stores glucose as glycogen when blood glucose is low and releases glucose when it is high
    • The liver converts all glucose to fat when blood glucose is high and releases amino acids when it is low
    • The liver stores glucose as glycogen when blood glucose is high and releases glucose when it is low
    • The liver stores glucose as protein at all times and releases fat when glucose is low
  16. Why does insulin act through surface receptors rather than by entering target cells?

    • It is a sugar that is recognised only by receptors inside the nucleus
    • It is a polypeptide that cannot readily cross the phospholipid bilayer, so it signals through a receptor
    • It is an enzyme that must be activated by glycogen before it can cross the membrane
    • It is a lipid that is repelled by the cytoplasm, so it must be stored in the membrane
  17. Put these events in the most likely order after a rise in blood glucose: 1 glucose enters cells, 2 insulin is secreted by beta cells, 3 blood glucose returns to normal, 4 glycogen synthesis increases. Which sequence is correct?

    • 2, 4, 1, 3
    • 1, 2, 4, 3
    • 3, 2, 1, 4
    • 2, 1, 4, 3
  18. An isolated liver cell is treated with glucagon. Which measurement would most directly show increased glucose output?

    • A fall in glucose released as insulin binds to the cell
    • A rise in glucose released into the medium as glycogen is broken down
    • No change because liver cells lack glucagon receptors
    • A rise in stored glycogen because glycogenesis is activated
  19. Blood glucose is 5.0 mmol per dm3 and a hormone causes liver output to rise so that blood glucose increases by 30 per cent. What is the new value?

    • 1.5 mmol per dm3
    • 8.0 mmol per dm3
    • 6.5 mmol per dm3
    • 3.5 mmol per dm3
  20. Which explanation best accounts for insulin and glucagon having opposite effects on the same liver cells?

    • Insulin acts only on the liver and glucagon acts only on muscle, so their effects never overlap
    • They bind the same receptor, but insulin is a lipid while glucagon is a sugar
    • They bind different receptors and activate opposing enzyme pathways for glycogen synthesis and breakdown
    • They are made by the same cell type, so one cancels the other in the bloodstream

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