gluconeogenesis

Question 1

what is gluconeogenesis

Answer 1

metabolic pathway by which organisms make glucose from non-carb carbon substrate
like pyruvate, lactate, glycerol + glucogenic AA

Question 2

how is gluconeogenesis activated and where can it occur

Answer 2

activated by glucagon - when blood glucose conc is low - avoids hypoglycaemia
in liver (lactate, alanine, glycerol)
in kidneys (lactate, glutamine, glycerol)

Question 3

during fasting, when does gluconeogenesis occur

Answer 3

liver glycogenolysis imp to maintain constant blood glucose level
when liver glycogen depleted - gluconeogenesis takes over –> requires source of carbon + energy

Question 4

describe cori cycle and how glycogenesis occurs in it

Answer 4

contracting muscles:
glucose-glycolysis-> pyruvate-lactate dehydrogenase-> lactate
L MOVES INTO LIVER
liver:
lactate-LDH-> pyruvate- gluconeogenesis-> glucose
MOVES BACK INTO MUSCLES
ITS A CYCLE - NO NEW GLUCOSE SYNTHESISED

Question 5

describe how gluconeogenesis happens from fatty acids

Answer 5

1. fatty acid oxidation makes ATP for GNG
2. also makes acetyl CoA + NADH = inhibits PDC
3. conversion of pyruvate -> acetyl CoA inhibited –> more pyruvate left for GNG + prevents loss of C in CO2
4. acetyl CoA activates pyruvate carboxylase for GNG

Question 6

describe how gluconeogenesis happens from AA

Answer 6

glycogenic AA = supply C for GNG

NOT LEUCINE OR LYSINE

Question 7

draw the diagram of gluconeogenesis from pyruvate

Answer 7

see diagram of glycolysis + gluconeeogenesis