Topic 6H: Homeostasis and Blood Glucose

Question 1

Binding of insulin leads to an increase in the rate of respiration in cells.

Explain how. [2]

Answer 1

1. Leads to more carrier (proteins) for glucose;
2. More glucose (for respiration) enters cell

Question 2

Describe the role of glucagon in gluconeogenesis. [2]

Answer 2

1. (Attaches to receptors in target cells and) activates enzymes;
2. Glycerol/fatty acids/amino acids into glucose

Question 3

Explain how increasing a cell’s sensitivity to insulin will lower the blood glucose concentration. [2]

Answer 3

1. (More) insulin binds to receptors;
2. (Stimulates) uptake if glucose by channel/carrier/transport proteins

Question 4

Explain how inhibiting adenylate cyclise may help to lower the blood glucose concentration. [3]

Answer 4

When glucagon/adrenaline binds to its receptors:
1. Less/no ATP is converted to cyclic AMP/cAMP;
2. Less/no kinase is activated;
3. Less/no glycogen is converted to glucose
OR
Less/no glycogenolysis

Question 5

Give two reasons why pancreas transplants are not used for the treatment of type II diabetes. [2]

Answer 5

1. (Usually) Type II produce insulin;
2. Receptors less sensitive/responsive (to insulin);
3. (Treated / controlled by) diet/exercise

Question 6

Give two ways in which people with type 1 diabetes control their blood glucose concentration. [2]

Answer 6

1. Treat with insulin (injection);
2. (Control) diet

Question 7

Explain why a change in the primary structure of insulin prevents it from binding to its receptor. [2]

Answer 7

1. Changes tertiary structure;
2. No longer complementary (to receptors)

Question 8

Diabetes with low blood glucose concentration can be treated with glucagon injections. Explain how the glucagon would affect the person’s blood glucose concentration. [2]

Answer 8

1. Glycogen to glucose / glycogenolysis by activating enzymes;
2. Gluconeogenesis

Question 9

A glucose biosensor is an instrument used to measure glucose concentration. It is better to use a biosensor than the Benedict’s test to measure the concentration of glucose in a sample of blood.

Suggest two reasons why. [2]

Answer 9

1. (Only detects glucose whereas) Benedict’s detects (all) reducing sugars;
2. Qualitative;
3. More sensitive;
4. Colour of blood masks result;
5. Can monitor blood glucose concentration continuously