3.6.4.2 Control of blood glucose concentration Flashcards
What factors influence blood glucose concentration?
“Factors include diet (carbohydrates broken down into glucose), glycogenolysis in the liver, gluconeogenesis (formation of glucose from non-carbohydrates), and glucose uptake by cells.”
What is glycogenesis and where does it occur?
“Glycogenesis is the formation of glycogen from glucose, occurring in the liver and muscle cells.”
What is glycogenolysis and where does it occur?
“Glycogenolysis is the breakdown of glycogen to glucose, primarily occurring in the liver.”
What is gluconeogenesis and where does it occur?
“Gluconeogenesis is the synthesis of glucose from non-carbohydrate sources, such as glycerol and amino acids, in the liver.”
How does insulin attach to target cells?
“Insulin binds to specific receptors on the surface membranes of target cells, such as muscle and liver cells.”
How does insulin control glucose uptake?
“Insulin regulates the inclusion of glucose channel proteins in the membranes of target cells, increasing glucose uptake.”
What enzymatic process does insulin activate?
“Insulin activates enzymes that convert glucose to glycogen (glycogenesis).”
How does glucagon attach to target cells?
“Glucagon binds to specific receptors on the surface membranes of target cells, such as liver cells.”
What enzymatic processes does glucagon activate?
“Glucagon activates enzymes that convert glycogen to glucose (glycogenolysis) and enzymes that convert glycerol and amino acids into glucose (gluconeogenesis).”
How does adrenaline influence blood glucose concentration?
“Adrenaline binds to receptors on target cells and activates enzymes that convert glycogen to glucose (glycogenolysis).”
What is the second messenger model for adrenaline and glucagon?
“The second messenger model involves hormone binding to a receptor, activating adenylate cyclase, which converts ATP to cyclic AMP (cAMP). cAMP activates protein kinase, leading to glycogenolysis.”
What causes type I diabetes?
“Type I diabetes is caused by the immune system attacking and destroying beta cells in the pancreas, resulting in little or no insulin production.”
How is type I diabetes controlled?
“Type I diabetes is controlled by regular insulin injections.”
What causes type II diabetes?
“Type II diabetes is caused by insulin resistance in target cells and/or insufficient insulin production by the pancreas.”
How is type II diabetes controlled?
“Type II diabetes is controlled by dietary management, exercise, and sometimes medication or insulin therapy.”
What positions do health advisers take regarding type II diabetes?
“Health advisers emphasise reducing sugar and refined carbohydrate intake, promoting exercise, and implementing public health campaigns.”
What positions does the food industry take regarding type II diabetes?
The food industry often promotes voluntary sugar reduction and product labelling but may resist regulatory measures.
Describe the role of glucagon in gluconeogenesis.
- (Attaches to receptors on target cells and) activates/stimulates enzymes;
Reject ‘produces enzymes’.
- Glycerol/amino acids/fatty acids into glucose;
Reject ‘glucagon converts’ as context suggests enzyme action.
Reject occurs in pancreas.
Explain how inhibiting adenylate cyclase may help to lower the blood glucose concentration.
- Less/no ATP is converted to cyclic AMP/cAMP;
- Less/no kinase is activated;
- Less/no glycogen is converted to glucose
OR
Less/no glycogenolysis;
Explain why a pancreas transplant would not be a suitable treatment for type 2 diabetes.
- Type II produces insulin
- Cells/receptors are less sensitive/responsive (to insulin)
OR
Faulty insulin receptors; - (treated/controlled by) diet/exercise
Adrenaline binds to receptors in the plasma membranes of liver cells. Explain how this causes the blood glucose concentration to increase.
- Adenylate cyclase activated / cAMP produced / second messenger produced;
- Activates enzyme(s) (in cell so) glycogenolysis / gluconeogenesis occurs / glycogenesis inhibited;
Explain why a change in the amino acid sequence of insulin could prevent insulin from binding to its receptors.
- Changes tertiary structure;
Reject change in tertiary structure of receptor.
- No longer complementary (to receptor);
Reject ‘active site’ or reference to enzyme or
substrate.
Give two ways in which people with type 1 diabetes control their blood
glucose concentration.
- Treat with insulin (injection/infusion);
- (Control) diet/control sugar intake;
- Accept ‘(regular) exercise
