3.6.4.2 Control of blood glucose (Unit 6 Homeostasis)

Question 1

Define glucoNEOgenesis

Answer 1

Formation of new glucose from amino acids and glycerol.

Question 2

Define glycogenolysis

Answer 2

Hydrolysis of glycogen into glucose

Question 3

Define glycogenesis

Answer 3

Formation of glycogen from glucose.

Question 4

What is lysis?

Answer 4

Splitting

Question 5

What is genesis?

Answer 5

Creating

Question 6

Why does blood glucose rise and then fall after a meal?

Answer 6

Question 7

Why does blood glucose increase in the presence of glucagon ?

Answer 7

Question 8

Outline the 2nd messenger model of adrenaline action

Answer 8

Question 9

Where are the hormones that regulate blood glucose secreted?

Answer 9

Islets of langerhan

Question 10

What do B cells secrete? And when?

Answer 10

Insulin

When blood glucose has INcreased

Question 11

What do a Cells secrete? And when?

Answer 11

Glucagon

When glucose is a gone

Question 12

How does insulin lower blood glucose?

Answer 12

Hormone that travels through the blood:
To respiring cells like muscle cells,
and binds to insulin receptors on them.
Causing glucose channels to open
Glucose diffuses in and is used in cellular respiration.
And:
To hepatocytes/receptors on the liver, which insulin binds to and which triggers enzymes involved in glycogenesis.

Question 13

How does adrenaline increase blood glucose?

Answer 13

Hormone that travels through the blood:
To respiring cells like muscle cells,
and binds to glucagon receptors on them.
Triggering the 2nd messenger model of enzyme action.
Adenylate cyclase catalyses the conversion of ATP->cAMP
cAMP is the 2nd messenger that activates protien Kinase to begin glycogenolysis and gluconeogenesis

And:
To hepatocytes/receptors on the liver, which insulin binds to and which triggers enzymes involved in glycogenolysis and gluconeogenesis.

Question 14

Describe the effects of insulin

Answer 14

Binds to specific receptors in the liver and muscles
Increases permeability of membranes to glucose – carrier proteins are activated
Activates enzymes to turn glucose into glycogen in glycogenesis (in liver for storage)
Increases the rate of respiration in muscles
Increases the conversion of glucose into fat

Question 15

Describe the effects of glucagon

Answer 15

Binds to specific receptors in the liver and muscles
Activates enzymes to turn glycogen into glucose (especially in the liver) in glycogenolysis
Promotes making glucose form fatty acids and amino acids in gluconeogenesis
Decreases the rate of respiration in muscles

Question 16

Describe the second messenger model

Answer 16

Adrenaline binds to the specific receptors on target cells (the liver)
The enzyme adenyl cyclase changes shape and is activated
Adenyl cyclase catalyses conversion of ATP to cyclic AMP
Cyclic AMP activates a protein kinase
Cyclic AMP and protein kinase stimulates glycogenolysis (conversion of glycogen to glucose)

This provides more glucose for respiration