Glucose Disposal

Question 1

Intolerant

Answer 1

Normal fasting glucose but a sluggish clearance

Question 2

Diabetic

Answer 2

Fasting hyperglycemia

unable to get rid of glucose and will often start with high BG

Question 3

What is secreted when glucose levels are low? Where?

Answer 3

Glucagon at alpha cells

Question 4

What is secreted when glucose is high? Where

Answer 4

Insulin at beta cells (Islet of Langerhans)

Question 5

Insulin Resistant

Answer 5

need to secrete more insulin in order to get rid of the glucose

Question 6

What is insulin intolerant?

Answer 6

Secreting more insulin but not enough to get over resistance. Thus can’t respond to the high levels of BG, so secreting high level of insulin

Hyperinsulinemia

Question 7

What is Types 2 Diabetes?

Answer 7

Beta-exhuasted

• not able to secrete much insulin, thus not able to respond to the glucose
• not able to maintain basal levels

Question 8

Two forms of Starch:

Answer 8

• Amylose

- Amylopectin

Question 9

Amylose

Answer 9

• linear, forms helices
• difficult for amylases to penetrate
• flatulence

Question 10

Amylopectin

Answer 10

• Branched

- easy digestion/ hydrolysis (Easy for amalyase to breakdown)

Question 11

The glycemic index

Answer 11

describes the post-prandial glucose response

Question 12

Removal of glucose from bloodstream in liver - what transporter?

Answer 12

GLUT2

- insulin independent

Question 13

Removal of glucose from bloodstream- in muscle?

Answer 13

GLUT4

• insulin dependent
• has a high capacity of getting rid of glucose

Question 14

What is the purpose of adding a phosphate to glucose?

What phosphate group?

Answer 14

To trap the glucose inside the cell, thus is now charged and can’t move across.

Hexokinase

Question 15

Glycogen synthesis is regulated by what?

Answer 15

Reverse phosphorlyation

Question 16

When dephosphorylation occurs, is it active or inactive?

Answer 16

Active

Glucose stimulates it

Question 17

What catalysed dephosphorylation?

Answer 17

Phosphates (PP1)

Question 18

When phosphorlyation occurs, is it active or inactive?

Answer 18

Inactive

Question 19

What catalyses phosphorylation?

Answer 19

Kinases

Question 20

What does insulin stimulate?

Answer 20

Insulin stimulates PPI, which causes GS to be active and dephosphorylate.

Question 21

What stimulates phosphofructokinase (PFK)?

Answer 21

AMP, low energy charge/ level (of ADP)

Question 22

How can insulin cause an increase in glycolysis?

Answer 22

Glycogenesis is anabolic (thus requiring ATP). As a result ATP levels drop and ADP levels increase.

This drop in energy charge stimulates PFK, which sitmulates catabolic pathway - oxidation of glucose

Question 23

What are levels of blood glucose and liver glucose

Answer 23

they are the same

Question 24

Purpose of glucokinase

Answer 24

Converts G –>G6P

Question 25

Relationship between G6P and blood glucose

Answer 25

As G6P increases so blood glucose rises

Question 26

What can G6P stimulate?

Answer 26

can stimulate inactive GS and phosphorylate GS

Question 27

Push mechanism - liver

Answer 27

Glycogenesis will respond to BG without insulin

- However insulin will stimualte glycogen synthase further

Question 28

Muscle

Answer 28

[G6P] never gets high enough to stimulate GS

- insulin dependent

Question 29

Glucokinase

• Where it works?
• present ?
• purpose

Answer 29

• only works on glucose (high levels of glucose)
• not inhibited by G6P
• only present in liver, beta cells
• responsive to changes in glucose blood

Question 30

Hexokinase

Answer 30

• works on any sugar 6C
• low levels of glucose
• inhibited by G6P- if there are too many G6P not used, then will build up and inhibit hexokinase
• easily saturated with glucose
• present in all other tissues

Question 31

What is required for the incorporation of glucose into glycogen chain

Answer 31

ATP

G–> G6P, UDP –> UTP