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Flashcards in Carbohydrates Metabolism Deck (19):
1

What is the rate limiting step in Glycolysis?
Name the activators and inhibitors of it.

PFK-1. Activated by AMP, F2,6,BP (dephosphorylated state)
Inhibited by: ATP, citrate (phosphorylated state)

2

Which enzyme produces the only NADH in the Glycolysis pathway? what are the substrates involved?

Glyceraldehyde 3-P Dehydrogenase. Converts G3P to 1,3 BPG.

3

Enzyme responsible for Last irreversible step in Glycolysis
Specify regulations of this enzyme.

Pyruvate Kinase.
Activated by F1,6,BP and Insulin. Active in the dephosphorylated form.
Inhibited by Glucagon, ATP, Alanine. Inactive in the phosphorylated form.

4

What causes Tarui Disease?

Deficiency in PFK1: Hemolytic anemia

5

Where does Gluconeogenesis occur?

Liver, kidney, small intestine

6

What is the first step enzyme in Gluconeogenesis? Where is it located? Activators and inhibitors?

Pyruvate Carboxylase: located in mitochondria.
Converts Pyruvate to Oxaloacetate.
Activated by: Acetyl CoA and cortisol.

7

Rate limiting step of Gluconeogenesis. Activators and Inhibitors

Fructose 1,6 Biphosphotase. Activated by Cortisol and Citrate. Inhibited by AMP and F2,6BP.

8

What is Fructose 1,6-biphosphotase deficiency?

Gluconeogenesis disorder: similar to Tarui disease. Hypoglycemia.

9

Von Gierke disease

Deficiency in the G-6 Phosphatase of Gluconeogenesis.: hypoglycemia, lactic acidosis.

10

Fanconi-Bickel Syndrome

mutation in GLUT 2 transporter.

11

Pathway of Glucose to Fructose

Glucose-Sorbitol-Fructose
Enzymes: Aldose reductase, Sorbitol dehydrogenase.

12

What causes Sorbitol accumulation

Deficiency in the enzyme Sorbitol Dehydrogenase which converts Sorbitol to Fructose.

13

Rate limiting enzyme of Galactose metabolism

GALT

14

What causes Galactosemia?

Deficiency in GALT: leads to accumulation of Galactic
Deficiency in Galactokinase: leads to accumulation of galactose and galacticol in blood and urine.

15

Rate limiting step of PPP and it's function

G6P Dehydrogenase: reduces NADP to NADPH and oxidizes G6P to 6-phosphoglucono-lactone. Part of the "Oxidative" phase. Inhibited by NAPDH

16

Which cells have the highest PPP activity?

phagocytic cells

17

What is the Rate Limiting Enzyme in Glycogenesis and the substrates involved?
In which form is it active?

Glycogen Synthase. Converts UDP-Glucose to Glycogen.
It is active in the dephosphorylated form.

18

What is the branching enzyme used in Glycogenesis

glucose 4:6 transferase

19

What is the Rate limiting enzyme of Glycogenolysis?
What co-factor does it use?
In which state is it active?

Glycogen Phosphorylase. Uses B6 as co-factor.
Active in the phosphorylated form.