Thompson 4

Question 0

What 3 steps in GNG are not direct reversals of Glycolysis? (What intermediate to what intermediate). Poorly worded. What steps in glycolysis are irreversible and thus need other enzymes not found in glycolysis?

Answer 0

Pyruvate to PEP
f16bp to f6p
G6P to glucose

Question 1

What are the main 3 precursors of glucose in GNG?

Answer 1

lactate, glycerol, amino acids.

Question 2

GNG is primarily in what organ?

Answer 2

Liver.

Question 3

GNG requires ___ ATP equivalents per glucose.

Answer 3

6.

Question 4

Which steps require ATP in GNG?

Answer 4

Pyruvate to OAA.
OAA to PEP.
3PG to 13BPG

Question 5

Lactate to pyruvate via what enzyme?

Alanine to pyruvate via what enzyme?

Answer 5

Lactate dehydrogenase.

Alanine aminotransferase.

Question 6

Pyruvate to OAA via what enzyme? Occurs in what organelle? What cofactor is needed?

Answer 6

Pyruvate carboxylase. Mitochondria. Biotin.

Question 7

OAA to PEP requires _____.

Answer 7

GTP.

Question 8

As compared to lacate–> PEP, what step does pyruvate —> PEP creates NADH?

Answer 8

Malate to OAA in cytosol. When lactate is precursor, the OAA goes straight to PEP.

Question 9

F26BP is made by what enzyme? What does it activate? What does it inhibit?

Answer 9

PFK2. activates PFK1. Inhibits Fructose 1 6 bisphosphatase.

Question 10

What activates pyruvate carboxylase?

Answer 10

Acetyl CoA.

Question 11

From OAA to PEP, what enzyme?

Answer 11

phosphoenolpyruvate carboxykinase.

Question 12

Fasting can induce activity in which two enzymes in GNG?

Answer 12

Fructose 1 6 bisphosphatase

glucose 6 phosphatase.

Question 13

What is the Cori Cycle?

Answer 13

Glucose made in liver by GNG from lactate. Glucose used and turned into lactate in RBC. Lactate returns to liver for GNG.

Question 14

What does excessive ethanol do in regards to GNG?

Answer 14

Causes intermediates to be diverted to other pathways.
Pyruvate to lactate.
OAA to malate.

Question 15

What are the steps of glycogen synthesis?

Answer 15

Glucose + ATP –> G6P (hexokinase)
G6P –> G1P (phosphoglucomutase)
G1P + UTP–> UDP glucose (UDP glucose pyrophosphorylase)
UDP glucose –> Glycogen (4:6 transferase (branching enzyme), glycogen synthase).

Question 16

What are the steps of glycogen degradation?

Answer 16

Glycogen to glucose (debranching enzyme).

Glycogen to G1P (glycogen phosphorylase)
G1P to G6P (phosphoglucomutase)
G6P to glucose (glucose 6 phosphatase liver only).

Question 17

What enzyme removes the remaining single glucose attached in the alpha 1 6 manner in glycogen?

Answer 17

alpha 1 6 glucosidase

Question 18

What enzyme adds glucose to glycogen in alpha 1 4?

What enzyme adds glucose branch alpha 1 6?

Answer 18

glycogen synthase

4:6 transferase (branching enzyme)

Question 19

How does cAMP have reciprocal regulation of glycogen synthesis and degradation?

Answer 19

Protein Kinase A activity:
P-Glycogen synthase=inactive
P-Glycogen Phosphorylase=active
high cAMP, low E, wants glycogen breakdown

Question 20

Pompe disease is a deficiency in ________, leading to

Answer 20

alpha 1 4 glucosidase. lysosomes filled with glycogen.

Question 21

What enzymes catalyze irreversible reactions in glycolysis? What enzymes in GNG help account for these 3 irreversible reactions?

Answer 21

hexokinase, pfk1, pk.

g6p phosphatase, f16bisphosphatase, pyruvate carboxylase with pep carboxykinase.