gluconeogenesis

Question 1

brain depends on glucose as its primary fuel and _______ use glucose as their only fuel

Answer 1

red blood cells

Question 2

whole body needs ______ grams of glucose per day

Answer 2

160

Question 3

daily glucose requirement of brain

Answer 3

120 grams

Question 4

glucose present in body fluids

Answer 4

20 grams

Question 5

glucose readily available from glycogen

Answer 5

190 grams

Question 6

direct glucose reserves are sufficient to meet glucose needs for about _____

Answer 6

1 day

Question 7

gluconeogenesis is especially important during a longer period of

Answer 7

fasting or starvation

Question 8

where does gluconeogenesis occur

Answer 8

liver and kidney

Question 9

gluconeogenesis is the synthesis of glucose from

Answer 9

non-carbohydrate precursors

Question 10

glucogenesis converts _______ into _______

Answer 10

pyruvate

glucose

Question 11

major precursors of gluconeogenesis

Answer 11

lactate, amino acids, and glycerol

Question 12

pyruvate carboxylase (PC) is a ________ enzyme

Answer 12

mitochondrial

Question 13

other enzymes (besides PC) of gluconeogenesis is found in

Answer 13

cytoplasm

Question 14

oxaloacetate (OAA), a product of PC, is transported to cytoplasm via

Answer 14

malate shuttle

Question 15

rate-limiting step of gluconeogenesis

Answer 15

F1,6-BP –> F6P via fructose 1,6-bisphosphatase

Question 16

free glucose from gluconeogenesis can leave _____ and enter ______

Answer 16

liver

blood

Question 17

glucose 6-phosphatase is a gluconeogenesis enzyme located where

Answer 17

in the lumen of the ER

Question 18

a protein called ______ transports glucose 6-phosphate to ER

Answer 18

T1

Question 19

a protein called ______ transports inorganic phosphate back into cytosol

Answer 19

T2

Question 20

a protein called ______ transports glucose back to cytoplasm

Answer 20

T3

Question 21

gluconeogenesis “by-passes” the irreversible steps of glycolysis through 4 enzymes not present in glycolysis

Answer 21

pyruvate carboxylase

phosphoenolpyruvate carboxykinase (PEP carboxykinase)

Fructose 1,6-bisphosphatase

glucose 6-phosphatase

Question 22

gluconeogenesis makes ______ , it requires ______

Answer 22

glucose

ATP

Question 23

gluconeogenesis has ______ points of ATP/GTP consumption

Answer 23

3

Question 24

in glycolysis, what activates the rate limiting step (activates PFK)?

Answer 24

F-2,6-BP

AMP

Question 25

in glycolysis, what inhibits the rate limiting step (inhibits PFK)?

Answer 25

ATP citrate H+

Question 26

in gluconeogenesis, what activates the rate limiting step (fructose 1,6-bisphosphatase)?

Answer 26

citrate

Question 27

in gluconeogenesis, what inhibits the rate limiting step (fructose 1,6-bisphosphatase)?

Answer 27

F-2,6-BP AMP

Question 28

in glycolysis, what activates pyruvate kinase?

Answer 28

F-1,6-BP

Question 29

in glycolysis, what inhibits pyruvate kinase?

Answer 29

ATP alanine

Question 30

in gluconeogenesis, what activates pyruvate carboxylase?

Answer 30

acetyl CoA

Question 31

in gluconeogenesis, what inhibits pyruvate carboxylase

Answer 31

ADP

Question 32

in gluconeogenesis what inhibits phosphoenolpyruvate carboxykinase

Answer 32

ADP

Question 33

gluconeogenesis is favored when

Answer 33

blood glucose levels are low and glycogen stores are depleted

Question 34

glycolysis energy use yield net yield

Answer 34

use: 2 ATP yield: 4 ATP net yield: 2 ATP/glucose oxidized

Question 35

gluconeogenesis energy use yield net yield

Answer 35

use: 4 ATP, 2 GTP yield: 0 net yield: 6 ATP equivalents/glucose synthesized

Question 36

insulin always stimulates a

Answer 36

phosphatase

Question 37

glucagon always stimulates a

Answer 37

kinase

Question 38

insulin stimulates phosphoprotein phosphatase --> ______ is activated --> ______ is stimulated and ______ is inhibited

Answer 38

PFK2 glycolysis glucogenogenesis

Question 39

glucagon stimulates protein kinase A (PKA) --> ______ is activated --> ______ is inhibited and ______ is activated

Answer 39

fructose bisphosophatase 2 (FBPase2) glycolysis gluconeogenesis

Question 40

the concentration of fructose 2,6-BP, a signaling molecule that stimulates or inhibits glycolysis is controlled by a fi-functional enzyme with a kinase and phosphatase domains

Answer 40

phosphofructokinase 2 (PFK2) and fructose bisphosphatase 2 (FBPase2)

Question 41

the cori cycle: lactate produced in skeletal muscle and red blood cells can be converted back to: the pyruvate can enter the gluconeogenic pathway and regenerate:

Answer 41

pyruvate in the liver glucose (which was the source of the lactate)