Lecture 21 & 25 - Nuc & Glyc Regulation Flashcards Preview

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Flashcards in Lecture 21 & 25 - Nuc & Glyc Regulation Deck (17):
1

What compound negatively regulates adenylosuccinate reductase?

AMP

2

What regulates IMP dehydrogenase?

(-) GMP

3

PRPP synthetase is regulated by what compounds?

(+) Pi
(-) GMP, IMP, AMP (purine nucleotides)

4

A deficiency in nucleotide reductase would result in:
A. Greater [RNA]
B. Lesser [RNA]
C. Greater [DNA]

A. Greater [RNA]

5

Fumerate is an intermediate of _____ & may funnel into ____.

Purine synthesis; TCA Cycle

6

Production of carbamoyl-phosphate is regulated how?

(+) PRPP
(-) UTP

7

PRPP ---> _______ via enzyme ________ is the committed step of purine synthesis.

Phosphribosylamine; glutamine phosphoribosyl pyrophosphate amidotransferase

8

Irreversible reactions of glycolysis:
A. Hexokinase, phosphfructokinase, pyruvate kinase
B. Hexokinase, phosphofructokinase, G-3-P dehydrogenase
C. Hexokinase, enolase, pyrivate kinase

A. Hexokinase, phosphofructokinase, pyruvate kinase

9

Which stage of glycolysis is known as the "committed step?
A. Stage 3
B. Stage 2
C. Stage 1

C. Stage 1

10

(-) regulator of hexokinase

Glucose-6-P (product of reaction)

11

(-) regulator of liver glucokinase

Glucagon, F-6-P (fructose can enter into glycolysis in the liver)

12

(+) regulator of glucokinase

Glucose, fructose 1-P (substrate of glucokinase in the liver), insulin

13

(-) regulator of phosphofructokinase

ATP
Citrate

14

(+) regulator of phosphofructokinase

AMP
Fructose-2,6-BP (downstream product of this enyzme's product)

15

What does elevated [citrate] indicate to phosphofrucokinase?

A presence of many carbon skeletons available for use

16

High [BGL] produces a dephosphorylation of _____, which increases pyruvate/ATP production.
A. Enolase
B. Phosphofructokinase
C. Pyruvate kinase
D. Triose phosphate isomerase

C. Pyruvate kinase

17

Describe the changes to the dual-domain enzyme phosphofructokinase.

The PFK portion is a kinase. When blood glucose is high, ADP is phosphorylated to form ATP. This increases release of glucose from glycogen.

The FBPase is a phosphatase. With decreased blood glucose levels, ATP is dephosphorylated. This phosphorylation of ADP comes from the removal of the Pi from FBPase. This dephosphorylation produces greater gluconeogenesis.