Control Of Blood-Glucose Levels

Question 1

What is insulin?

Answer 1

• hormone released from beta cells in the pancreas when blood glucose concentration rises
• travels in the blood + attaches to receptors on the surfaces of almost all cells
• brings about changes inside the cell that lower the glucose concentration in the blood
• stops being release after blood-glucose concentration has been lowered

Question 2

What is insulin an example of?

Answer 2

Negative feedback

Question 3

When is glycogenesis used?

Answer 3

When blood-glucose concentration is too high

Question 4

When is glycogenolysis used?

Answer 4

When blood-glucose concentration is too low

Question 5

When is gluconeogenesis used?

Answer 5

When blood glucose concentration is too low

Question 6

Why can insulin not enter the cells?

Answer 6

Because it’s a peptide hormone

Question 7

What happens when insulin binds to the insulin receptor?

Answer 7

• glucose transporter vesicles fuse with the cell surface membrane
• causes these vesicles to change shape so they let more glucose into the cell
• activates tyrosine kinase

Question 8

Why is tyrosine kinase used?

Answer 8

• phosphorylates other enzymes to turn them from inactive to active which go on to reduce the blood glucose concentration

Question 9

What is glucose converted into?

Answer 9

Fat & glycogen

Question 10

What happens in glycogenesis?

Answer 10

Liver cell produce enzymes that convert glucose to glycogen which is stored in the liver cells

Question 11

What happens in glycogenolysis?

Answer 11

The liver produces enzymes that break down the glycogen stored in the cells to glucose

Question 12

What happens in gluconeogenesis?

Answer 12

The liver cells form glucose from glycerol and amino acids