Regulation of Blood Glucose

Question 0

Describe the 2nd messenger model

Answer 0

The hormone is the 1st messenger, it binds to specific receptors on cell surface membrane of target cells to form hormone-receptor complex
This complex activated an enzyme inside the cell resulting in production of a chemical that acts as 2nd messenger
2nd messenger causes series chemical changes that produce required response

Question 1

What are 3 common characteristics of hormones?

Answer 1

• produced by glands which secrete them into the blood
• carried in blood plasma to target cells which have receptors complementary to hormone
• effective in very small quantities but have widespread/long lasting effect

Question 2

What does the activated enzyme by adrenaline cause?

Answer 2

Conversion of ATP to cyclic AMP which acts as 2nd messenger which activated other enzymes to convert glycogen to glucose

Question 3

What are the groups of hormone-producing cells in the pancreas called?

Answer 3

Islets of Langerhans

Question 4

Which cells are larger and produce glucagon?

Answer 4

A - cells

Question 5

Which cells are smaller and produce insulin?

Answer 5

B-cells

Question 6

What are the 3 sources of blood glucose?

Answer 6

1-Diet by breakdown of carbs (starch)
2-breakdown of glycogen (glycogenolysis)
3-gluconeogenesis production of new glucose where liver combines glycerol and amino acids

Question 7

Which cells have glycoprotein receptors on their surface to combine with insulin?

Answer 7

All body cells except red blood cells

Question 8

What happens when insulin combines with receptors?

Answer 8

• tertiary structure change of glucose transport protein channels changing their shape allowing no more glucose into cells
• increase number of carrier molecules in cell surface membrane
• activation of enzymes that convert glucose into glycogen

Question 9

As a result of insulin combining with receptors what happens?

Answer 9

• increase rate of absorption of glucose into cells
• increase respiration rate which therefore use up more glucose
• increase conversion of glucose into glycogen (glycogenesis) in liver/muscle
• increase conversion rate of glucose to fat

Question 10

Which cells have receptors that bind with glucagon?

Answer 10

Only the liver

Question 11

What happens when glucagon combines with liver receptor cells?

Answer 11

• Activated enzymes that convert glycogen to glucose

- increase conversion of amino acids and glycerol into glucose (gluconeogenesis)

Question 12

What happens when adrenaline binds with receptors?

Answer 12

• activated enzymes which cause the breakdown of glycogen into glucose
• inactivates enzymes that synthesise glycogen from glucose