Glycolysis

Question 1

First step in Glycolysis

Answer 1

Glucose -> Glucose-6-phosphate

Enzyme: hexokinase (transferase)

• reaction is metabollically irreversible
• the product of the reaction allosterically inhibits hexokinase I, II, and III. This is an example of feedback inhibition
• reaction requires Mg2+, as a cofactor for ATP

Question 2

Second Step in Glycolysis

Answer 2

Enzyme: Glucose-6-phosphate isomerase (isomerase)

-subject to regulation through concentration Near Equilibrium reaction

Question 3

Third Step in Glycolysis

Answer 3

Enzyme: phosphofructokinase-1 (PFK-1)

• metabollically irreversible
• first commited step of glycosis since other substrates may enter glycolysis in a way that by-passes reactions one and two. Subject to intense regulation as a result

Question 4

4th step in glycolysis

Answer 4

Enzyme: 1,6-bisphosphate aldolase

• Near Equilibrium reaction
• produces glyceraldehyde and dihydroxyacetone phosphate (metabollic deadend)

Question 5

5th step in Glycolysis

Answer 5

Enzyme: triose phosphate isomerase (isomerase)

-near equilibrium reaction that is driven by the principle of mass action

-

Question 6

6th step in glycolysis

Answer 6

Enzyme: Glyceraldehyde-3-phosphate dehyrogenase (oxidoreductase)

NAD+ electron acceptor

Question 7

7th step in glycolysis

Answer 7

Enzyme:Phosphoglycerate kinase

-near equilibrium substrate-level phosphorylation

Question 8

8th step of glycolysis

Answer 8

Enzyme: Phosphoglycerate Mutase (Isomerase)

-near equilibrium reaction

Question 9

9th step of glycolysis

Answer 9

Enzyme: Enolase

-Magnesium is required to facilitate the forward reaction. Mg2+ stabilizes the terminal carboxylate group and catalyzes the dehydration reaction

Question 10

10th Step of Glycolysis

Answer 10

• substrate level phosphorylation
• reaction is metabollically irreversible
• Pyruvate Kinase (transferase)