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Flashcards in Thompson 4 Deck (22)
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Q

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?

A

Pyruvate to PEP
f16bp to f6p
G6P to glucose

1
Q

What are the main 3 precursors of glucose in GNG?

A

lactate, glycerol, amino acids.

2
Q

GNG is primarily in what organ?

A

Liver.

3
Q

GNG requires ___ ATP equivalents per glucose.

A

6.

4
Q

Which steps require ATP in GNG?

A

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

5
Q

Lactate to pyruvate via what enzyme?

Alanine to pyruvate via what enzyme?

A

Lactate dehydrogenase.

Alanine aminotransferase.

6
Q

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

A

Pyruvate carboxylase. Mitochondria. Biotin.

7
Q

OAA to PEP requires _____.

A

GTP.

8
Q

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

A

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

9
Q

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

A

PFK2. activates PFK1. Inhibits Fructose 1 6 bisphosphatase.

10
Q

What activates pyruvate carboxylase?

A

Acetyl CoA.

11
Q

From OAA to PEP, what enzyme?

A

phosphoenolpyruvate carboxykinase.

12
Q

Fasting can induce activity in which two enzymes in GNG?

A

Fructose 1 6 bisphosphatase

glucose 6 phosphatase.

13
Q

What is the Cori Cycle?

A

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

14
Q

What does excessive ethanol do in regards to GNG?

A

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

15
Q

What are the steps of glycogen synthesis?

A

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

16
Q

What are the steps of glycogen degradation?

A

Glycogen to glucose (debranching enzyme).

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

17
Q

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

A

alpha 1 6 glucosidase

18
Q

What enzyme adds glucose to glycogen in alpha 1 4?

What enzyme adds glucose branch alpha 1 6?

A

glycogen synthase

4:6 transferase (branching enzyme)

19
Q

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

A

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

20
Q

Pompe disease is a deficiency in ________, leading to

A

alpha 1 4 glucosidase. lysosomes filled with glycogen.

21
Q

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

A

hexokinase, pfk1, pk.

g6p phosphatase, f16bisphosphatase, pyruvate carboxylase with pep carboxykinase.