Lactate Shuttle, Gluconeogenesis and Regulation of Carbohydrate Metabolism

Question 1

how many ATP come from one round of the krebs cycle

Answer 1

10

Question 2

3 NADH+H ATP equivalent

Answer 2

7.5

Question 3

1 FADH2 ATP equivalent

Answer 3

1.5

Question 4

1 GTP/ATP ATP equivalent

Answer 4

1 ATP

Question 5

oxidative phosphorylation net ATP

Answer 5

32 ATP

Question 6

lactate forms when

Answer 6

hydrogens from NADH combine temporarily with pyruvate

Question 7

when hydrogens from NADH combine temporarily with pyruvate, it frees up NAD to …

Answer 7

accept additional hydrogens generated in glycolysis

Question 8

glycolytic flux in excess of mitochondrial capacity =

Answer 8

extra lactate production

Question 9

what enzyme has the highest Vmax of any glycolytic enzyme

Answer 9

lactate dehydrogenase

Question 10

the lactate shuttle suggests lactate may actually be fuel of choice during

Answer 10

exercise for heart and type I skeletal muscle fibers

Question 11

lactate produced in type II …

Answer 11

transported to and used in oxidative tissue

Question 12

main substrates that supply the carbon backbones needed for glucose synthesis

Answer 12

glycerol, lactate, and amino acids

Question 13

gluconeogenesis is somewhat the reverse of what other metabolic process but with what change

Answer 13

glycolysis; special enzymes are needed to work backwards

Question 14

gluconeogensis occurs mainly in the

Answer 14

liver

Question 15

the cori cycle utilizes _____ to produce ___

Answer 15

lactate; glucose

Question 16

the glucose-alanine cycle ___ ____ to produce ___

Answer 16

degrades protein; glucose

Question 17

both the cori cycle and the glucose alanine cycle do what

Answer 17

recycle glucose

Question 18

cori cycle steps

Answer 18

lactate from venous circulation —-> pyruvate —-> glucose —-> glycogen or arterial bloodstream

Question 19

glucose alanine cycle steps

Answer 19

alanine —> pyruvate —-> glucose

Question 20

by products of alanine converting to pyruvate

Answer 20

NH2 —> urea

Question 21

carbohydrate metabolism is regulated by

Answer 21

• concentrations of glycolytic enzymes hexokinase, PFK, and pyruvate kinase
• oxygen

Question 22

enzyme inhibitors

Answer 22

ATP & NADH

Question 23

enzyme activators

Answer 23

ADP and NAD

Question 24

rate limiting ezyme of glycolysis

Answer 24

PFK

Question 25

stimulators of glycolysis

Answer 25

ADP, AMP, P, increased pH

Question 26

inhibitors of glycolysis

Answer 26

ATP, CP, citrate

Question 27

glycogenolysis is controlled by

Answer 27

phosphorlyase

Question 28

phosphorylase is controlled by what 2 mechanisms

Answer 28

1. mediated by Ca released from the SR
2. mediated hormonally by the action of epinephrine