Control Of Blood Glucose Concentration

Question 1

What are hormones

Answer 1

Chemicals that are produced in glands and secreted directly into the blood

Question 2

Why do hormones only effect some cells

Answer 2

Only target cells have protein receptors on their cells surface ht are complementary to a specific hormone

Question 3

Factors that affect blood glucose concentration

Answer 3

• hydrolysis of carbohydrates
• rate of glycogenolysis
• rate of glucoeogenesis

Question 4

2 hormone that affect blood glucose concentration

Answer 4

Glucagon and insulin

Question 5

Glucagon

Answer 5

Increases blood glucose conc

Question 6

Insulin

Answer 6

Decreases blood glucose conc

Question 7

Where are insulin and glucagon made

Answer 7

Islets of langerhans in the pancreas

Question 8

What detects a fall in blood glucose

Answer 8

Alpha cells and they produce glucagon

Question 9

What detects a rise in blood glucose

Answer 9

Beta cells and produce insulin

Question 10

What is glycogenesis

Answer 10

Liver converts glucose into glycogen (storage polymer)

Question 11

Glycogenolysis

Answer 11

Liver hydrolyses glycogen into glucose which can diffuse into blood

Question 12

Gluconeogenesis

Answer 12

Liver converts glycerol and amino acids Into glucose

Question 13

Outline the role of glucagon when blood glucose concentration decreases

Answer 13

• Alpha cells in islets of langerhans in pancreas detect decrease and secrete glucagon into the blood stream
• glucagon attaches to receptors on target cells (liver) and activates enzymes for glycogenolysis and gluconeogenesis
• glucose diffuses from over into the blood stream

Question 14

Outline what happens when blood glucose concentration increases

Answer 14

• B cells in islets of langerhans in pancreas detect increase and secrete insulin into bloodstream
• insulin attaches to receptors on the surface of target cells
• controls uptake of glucose by regulating the inclusion of Channel proteins in the surface membranes of target cells
• activating enzymes for glycogenesis

Question 15

How does insulin lead to a decrease in blood glucose concentration

Answer 15

• Increases permeability of cells to glucose
• increases glucose concentration gradient
• triggers inhibition of enzymes for glycogenolysis

Question 16

How does insulin increase permeability of cells to glucose

Answer 16

• increase number of glucose carrier proteins
• triggers conformational changes which opens glucose carrier proteins

Question 17

Role of adrenaline

Answer 17

Increases the conversion of glycogen to glucose in the liver by activating enzymes that causes glycogenolysis

Question 18

Describe the secondary messenger model

Answer 18

1. Hormone adrenaline approaches transmembrane protein
2. Adrenaline binds to receptor causing it to change shape, activating an enzyme called adenylate cyclase
3. Activated adenylate cyclase coverts atp to cyclic AMP which acts a second messenger
4. The cAMP in turn changes the shape and activates protein kinase enzyme
5. The active protein kinase enzyme catalyse the conversion of glycogen to glucose

Question 19

Why is there a time lag between a change in blood glucose being detected

Answer 19

• hormone takes time to be produced and transported in blood