glucogenesis

Question 1

what is gluconeogenesis

Answer 1

• generates glucose from non carbohydrates like carbon, lactate, pyruvate, glycerol, glucogenic amino acids like Ala and glu

Question 2

why do we need gluconeogenesis

Answer 2

• brain and CNS use it for energy

Question 3

where does gluconeogenesis take place

Answer 3

90% in liver
10% in kidney

Question 4

what is similar to Hexokinase, pdk-1 and Pk from glycolysis

Answer 4

glucose 6-phosphatase, fructose bisphosphatase, and pyruvate carboxylase and pep carboxykinase

Question 5

how do you bypass pyruvate kinase

Answer 5

use pyruvate carboxylase and PEPCK (phosphoenolpyruvate carboxykinase)

Question 6

what does Pyruvate carboxy do

Answer 6

catalyze atp
- depends on biotin conversion of pyruvate to oxaloacetae

Question 7

where does pyruvate to oxalocetate happen

Answer 7

mitochondrial matrix

Question 8

what does PEPCK do

Answer 8

• gtp to convert oxalo to phosphoenolpyruvate through phosphorylation

Question 9

what is the energy cost of gluconeogenesis

Answer 9

• 2 atp
  -2 gtp
  2 atp
  = 6 net atp equivalents
  2 nadh

Question 10

what is glucokinase

Answer 10

is it really hexokinase isozyme of glycolysis

Question 11

what bypasses glucokinase

Answer 11

glucose 6 phosphatase

Question 12

why is gluconeogenesis in the liver

Answer 12

huge buffer for glucose so glucokinase never achieves equilibrium

Question 13

what is apart of gluconeogenesis but is not in the liver

Answer 13

pyruvate carboxylase and some PEP carboxylase they occur in the mito matrix

Question 14

what is reciprocal regulation

Answer 14

• turn one one and the other off

Question 15

what is the main control point in gluceogen

Answer 15

fructose 1,6 bisphosphatase

Question 16

which control points take place @ the same time

Answer 16

pfk and fructose 1,6 causing a substrate cycle or hydrolysis of atp

Question 17

what do substrate cycles do

Answer 17

• consume small amounts of atp but give a broadr range of control over metabolic rates

Question 18

where is muscle lactate transferred to

Answer 18

the liver where it is turned into glucose via gluconeogen. or cori cycle

Question 19

can gluconeogenesis start at lactate

Answer 19

yes, it is LDH in reverse direction

Question 20

what is the energy cost of gluconeogen from lactate

Answer 20

6 atp (2 atp, 2 gtp, 2 atp)
2 nadh then -2 nadh so 0 nadh used

Question 21

what is the cori cycle

Answer 21

• under anaerobic generate lactae
• muscle lactate is taken from bloodstream to liver
• gluconeogen starts w/ lactate dehydrogenase to convert lacctate to glucose where it is taken through bloodstream to muscle
  ldh path
  bloodstream –> liver–> bloodstream–. muscle
• used for energy and stored as glycogen