Control Of Glucose Concentration

Question 1

Describe the role of glucagon in gluconeogenesis (2)

Answer 1

1. (Attaches to receptors on target cells and) activates/stimulates enzymes;
   Reject ‘produces enzymes’.
2. Glycerol/amino acids/fatty acids into glucose;
   Reject ‘glucagon converts’ as context suggests enzyme action.
   Reject occurs in pancreas.

Question 2

Explain how inhibiting adenylate cyclase may help to lower the blood glucose concentration (3)

Answer 2

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 3

Using your knowledge of the kidney, explain why glucose is found in the urine of a person with untreated diabetes (3)

Answer 3

1. High concentration of glucose in blood/filtrate;
   Accept tubule for filtrate.
2. Not all the glucose is (re)absorbed at the proximal convoluted tubule;
   Reject no glucose is (re)absorbed.
3. Carrier/co-transport proteins are working at maximum rate OR
   Carrier/co-transport proteins/ are saturated;

Question 4

Explain why a pancreas transplant would not be a suitable treatment for type 2 diabetes (3)

Answer 4

1. Type II produces insulin
2. Cells/receptors are less sensitive/responsive (to insulin) OR Faulty insulin receptors;
3. (treated/controlled by) diet/exercise

Question 5

Adrenaline binds to receptors in the plasma membranes of liver cells. Explain how this causes the blood glucose concentration to increase (2)

Answer 5

1. Adenylate cyclase activated / cAMP produced / second messenger produced;
2. Activates enzyme(s) (in cell so) glycogenolysis / gluconeogenesis occurs / glycogenesis inhibited;