Catabolism - Glycolysis

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Questions and Answers

How many ATP molecules are created during the generating phase of glycolysis?

2 ATP

6 ATP

8 ATP

4 ATP (correct)

What is the net ATP production per glucose molecule in glycolysis?

6 ATP

4 ATP

2 ATP (correct)

0 ATP

How many NADH molecules are generated per glucose molecule in glycolysis?

2 NADH (correct)

0 NADH

3 NADH

1 NADH

Which reactions in glycolysis are irreversible?

All of the above Signup and view all the answers

Which phase of glycolysis requires ATP?

Preparative Phase Signup and view all the answers

How many ATP molecules are required during the preparatory phase of glycolysis?

2 ATP Signup and view all the answers

What is the role of Mg2+ cofactor in Reaction 1 of glycolysis?

It stabilizes the enzyme Signup and view all the answers

How does Reaction 2 of glycolysis proceed in the forward direction despite having a positive ΔG°?

It is coupled with an exergonic reaction Signup and view all the answers

What is the rate-limiting and committing step of glycolysis?

Reaction 3 Signup and view all the answers

What would be the effect on glycolysis if triose phosphate isomerase was not present/able to function?

Glycolysis would stop at Reaction 5 Signup and view all the answers

Which enzyme is responsible for Reaction 6 of glycolysis?

Glyceraldehyde-3-phosphate dehydrogenase Signup and view all the answers

What is the ΔG° for Reaction 8 of glycolysis?

4.4 kJ/mol Signup and view all the answers

Which enzyme is responsible for Reaction 9 of glycolysis?

Enolase Signup and view all the answers

Which Enzyme is responsible for the last step of glycolysis?

Pyruvate Kinase Signup and view all the answers

Which enzyme is responsible for the formation of fructose 1,6-bisphosphate?

Phosphofructosekinase 1(PFK-1) Signup and view all the answers

What is the main rate-limiting reaction in glycolysis?

Fructose 6-Phosphate to Fructose 1, 6-biphosphate Signup and view all the answers

Aldolase catalyzes the formation of...

Dihydroxyacetone phosphate + Glyceralaldehyde 3-phosphate Signup and view all the answers

Conversion fo G-6-P to F-6-P is catalyzed by

Phosphoglucose isomerase Signup and view all the answers

Phosphoglycerate kinase will..

Remove a phosphate from biphosphoglycerate Signup and view all the answers

Enolase produces

H2O + Phosphoenolpyruvate Signup and view all the answers

Pyruvate kinase produces...

Pyruvate + ATP Signup and view all the answers

Which enzyme(s) requires magnesium as a cofactor?

Pyruvate kinase Signup and view all the answers

PFK phosphorylates..

F-6-P Signup and view all the answers

Triose phosphate isomerase catalyzes the...

Conversion of DHAP to G3P Signup and view all the answers

Study Notes

ATP Production in Glycolysis

A total of 4 ATP molecules are generated during the payoff phase of glycolysis.
The net ATP production per glucose molecule in glycolysis is 2 ATP, considering 2 ATP are used in the preparatory phase.
Glycolysis generates 2 NADH molecules per glucose molecule.

Irreversible Reactions in Glycolysis

The irreversible reactions in glycolysis are catalyzed by hexokinase, phosphofructokinase (PFK), and pyruvate kinase.

ATP Requirements in Glycolysis

The preparatory phase of glycolysis requires 2 ATP molecules for phosphorylation of glucose and fructose 6-phosphate.

Role of Mg2+ in Glycolysis

The Mg2+ cofactor in Reaction 1 stabilizes the negative charges on ATP, facilitating its hydrolysis to ADP and inorganic phosphate.

Reaction Direction in Glycolysis

Reaction 2 can proceed in the forward direction despite a positive ΔG° due to the low concentration of products, utilizing Le Chatelier's principle.

Rate-Limiting Step of Glycolysis

The rate-limiting and committing step of glycolysis is catalyzed by phosphofructokinase (PFK), which converts fructose 6-phosphate to fructose 1,6-bisphosphate.

Effect of Triose Phosphate Isomerase Absence

Without the function of triose phosphate isomerase, the conversion of dihydroxyacetone phosphate to glyceraldehyde 3-phosphate would be impaired, disrupting glycolysis.

Key Enzymes in Glycolysis

The enzyme responsible for Reaction 6 is glyceraldehyde 3-phosphate dehydrogenase (GAPDH).
Reaction 8 is catalyzed by phosphoglycerate mutase, with a ΔG° of approximately 0.
Enolase is responsible for Reaction 9, converting 2-phosphoglycerate to phosphoenolpyruvate.
The last step of glycolysis is catalyzed by pyruvate kinase.
The enzyme responsible for forming fructose 1,6-bisphosphate is phosphofructokinase (PFK).
The main rate-limiting reaction in glycolysis is also catalyzed by PFK.

Additional Enzymatic Actions and Requirements

Aldolase catalyzes the formation of glyceraldehyde 3-phosphate and dihydroxyacetone phosphate.
The conversion of glucose-6-phosphate (G-6-P) to fructose-6-phosphate (F-6-P) is catalyzed by phosphoglucose isomerase.
Phosphoglycerate kinase catalyzes the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate, producing ATP.
Enolase produces phosphoenolpyruvate (PEP) from 2-phosphoglycerate.
Pyruvate kinase produces pyruvate from phosphoenolpyruvate.
Enzymes such as hexokinase, phosphofructokinase, and pyruvate kinase require magnesium as a cofactor.
Phosphofructokinase (PFK) phosphorylates fructose 6-phosphate to fructose 1,6-bisphosphate.
Triose phosphate isomerase catalyzes the interconversion of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate.

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Description

Test your knowledge of the phases and reactions involved in glycolysis with this informative quiz. Explore the preparative and ATP-generating phases, as well as the specific enzymes and reactions that occur. Challenge yourself with questions about glucose trapping and the overall overview of glycolysis.