Chapter 17: Gluconeogenesis

Question 1

What is gluconeogenesis?

Answer 1

Synthesis of glucose from pyruvate

Question 2

Where does gluconeogensis occur?

Answer 2

In the liver mostly, can sometimes happen in the kidney

Question 3

Gluconeogensis is especiialy important during periods of what?

Answer 3

Starvation and fasting

Question 4

Glucose is the primary fuel for what?

Answer 4

The brain

Question 5

Glucose is the ONLY fuel for what?

Answer 5

Red blood cells

Question 6

Pyruvate can be formed from muscle-derived __________ in the liver by ____________ ___________________ .

Answer 6

Lactate, lactate dehydrogenase

Question 7

The carbon skeletons of some amino acids can be converted into ____________ ______________.

Answer 7

Gluconeogenic intermediates.

Question 8

Glycerol can be converted into ______________________ ____________ which can be processed by gluconeogensis or glycolysis

Answer 8

Dihydroxyacetone phosphate

Question 9

The three irreversible steps in glycolysis must be bypassed in gluconeogenesis:

Answer 9

Hexokinase, phosphofructokinase, pyruvate kinase

Question 10

The formation of phosphoenolpyruvate from pyruvate requires two enzymes:

Answer 10

Pyruvate carboxylase and
phosphoenolpyruvate carboxykinase

Question 11

The conversion of pyruvate into phosphoenolpyruvate begins with the formation of what?

Answer 11

Oxaloacetate

Question 12

Pyruvate carboxylase requires the vitamin _______ as a cofactor

Answer 12

Biotin

Question 13

What forms oxaloacetate?

Answer 13

Pyruvate carboxylase

Question 14

The formation of oxaloacetate by pyruvate carboxylase occurs in the:

Answer 14

Mitochondria

Question 15

Oxaloacetate is reduced to _________ and transported into the ___________

Answer 15

Maltate, cytoplasm

Question 16

After oxaloacetate is reduced to malate and transported into the cytoplasm, it is reoxidized to _____________ with the
generation of ______________ ________

Answer 16

Oxaloacetate. cytoplasmic NADH

Question 17

Phosphoenolpyruvate is synthesized from oxaloacetate by _________________________ _________________

Answer 17

Phosphoenolpyruvate carboxykinase

Question 18

Oxaloacetate is shuttled into the cytoplasm and converted into what?

Answer 18

Phosphoenolpyruvate

Question 19

Phosphoenolpyruvate is metabolized by the enzymes of ____________ in the reverse direction until the next irreversible
step, which is?

Answer 19

Glycolysis, hydrolysis of fructose 1,6-bisphosphate

Question 20

What is the enzyme catalyzing the hydrolysis of fructose 1,6-bisphosphate?

Answer 20

Fructose 1,6- bisphosphatase, an allosteric enzyme.

Question 21

True or False:
The generation of free glucose is an important control
point

Answer 21

True

Question 22

The generation of free glucose, which occurs essentially only in the:

Answer 22

Liver

Question 23

The generation of free glucose is the __________ step in gluconeogenesis

Answer 23

Final

Question 24

After the germination of free glucose, Glucose 6-phosphate is transported into?

Answer 24

The lumen of the endoplasmic reticulum

Question 25

Glucose 6-phosphatase is on the inner or outer surface of the endoplasmic reticulum?

Answer 25

Inside

Question 26

Glucose 6-phosphatase catalyzes the formation of ____________ from __________ _-____________

Answer 26

Glucose, glucose 6-phosphate

Question 27

How are gluconeogenesis and glycolysis regulated in a cell?

Answer 27

One pathway is relatively inactive while the other is highly active

Question 28

The rationale for reciprocal regulation is that:

Answer 28

- Glycolysis will predominate when glucose is abundant - Gluconeogenesis will be highly active when glucose is scarce.

Question 29

The interconversion of what and what is a key regulatory site?

Answer 29

Fructose 1,6-bisphosphate and fructose 6-phosphate

Question 30

Additionally, glycolysis and gluconeogenesis are reciprocally regulated at the interconversion of what and what?

Answer 30

Phosphoenolpyruvate and pyruvate

Question 31

If ATP is needed, _____________ predominates. If glucose is needed, ___________________ is favored

Answer 31

Glycolysis, gluconeogenesis

Question 32

In the liver, the rates of glycolysis and gluconeogenesis are adjusted to maintain:

Answer 32

Blood-glucose levels

Question 33

The key regulator of glucose metabolism in the liver is:

Answer 33

Fructose 2,6-bisphosphate

Question 34

Fructose 2,6-bisphosphate stimulates _________________________ and inhibits _,_-_____________________. These are located own the same polypeptide chain

Answer 34

Phosphofructokinase, fructose 1,6-bisphosphatase

Question 35

Phosphofructokinase and fructose 1,6- bisphosphatase are located on the same polypeptide chain, what arrangement is this called?

Answer 35

Bifunctional enzyme

Question 36

When blood glucose is low, the hormone ______________ is secreted

Answer 36

Glucagon

Question 37

The glucagon signaling pathway leads to the phosphorylation of the ______________ enzyme

Answer 37

Bifunctional

Question 38

Bifunctional enzyme inhibits the ___________ and stimulates the ___________________

Answer 38

Kinase, phosphatase

Question 39

Insulin normally inhibits or activates gluconeogensis?

Answer 39

Inhibits

Question 40

The enzymes of gluconeogenesis, especially ______, are active, leading to abnormally high levels of blood glucose

Answer 40

PEPCK

Question 41

Muscle and liver display interorgan cooperation in a series of reactions called

Answer 41

Cori cycle

Question 42

__________ produced by muscle during contraction is released into the blood

Answer 42

Lactate

Question 43

Liver removes the ___________ and converts it into ___________ which can be released into the blood

Answer 43

Lactate, glucose