Glycolysis

Question 1

What is the general reaction for glycolysis?

Answer 1

Glucose > 2 pyruvate

Question 2

Where in a cell does glycolysis occur?

Answer 2

Cytosol

Question 3

What are the 4 stages of glycolysis?

Answer 3

Activation - uses ATP
Splitting of the 6 carbon molecule into two 3 carbon molecules
Oxidation - removing 2 H atoms
Synthesis of ATP

Question 4

What are the 3 reactions in the activation stage?

Answer 4

glucose > glucose-6-phosphate > fructose-6-phosphate > fructose-1,6,-bisphosphate

Question 5

What enzyme converts glucose to glucose-6-phosphate?

Answer 5

Hexokinasese - in nearly all cells.

Glucokinase - in liver and beta-cells of the pancreas

Question 6

What enzyme converts glucose-6-phosphate to fructose-6-phosphate?

Answer 6

Phosphoglucose isomerase

Question 7

What enzyme converts fructose-6-phosphate to fructose-1,6-bisphosphate?

Answer 7

Phosphofructokinase

Question 8

What are the products of the hydrolysis of fructose-1,6-bisphosphate?

Answer 8

glyceraldehyde-3-phosphate

dihydroxyacetone phosphate

Question 9

What enzyme catalyses the hydrolysis of fructose-1,6-bisphosphate?

Answer 9

Aldolase A

Question 10

What enzyme converts dihydroxyacetone phosphate into glyceraldehyde-3-phosphate?

Answer 10

Triose phopshate isomerase

Question 11

What is the oxidation reaction in glycolysis?

Answer 11

Glyceraldehyde-3-phosphate > 1,3-bisphosphoglycerate

Question 12

What enzyme catalyses the oxidation reaction of glyceraldehyde-3-phosphate into bisphosphoglycerate using NAD+?

Answer 12

Glyceraldehyde-3-phosphate dihydrogenase

Question 13

What are the series of reactions in ATP production in glycolysis?

Answer 13

1,3-bisphosphate > 3-phosphoglycerate > 2-phosphoglycerate > phosphoenol pyruvate > pyruvate

Question 14

Which reactions produce ATP from ADP?

Answer 14

1,3-bisphosphate > 3-phosphoglycerate
and
phosphoenol pyruvate > pyruvate

Question 15

What is the enzyme which catalyses the reaction of 1,3-bisphosphate into 3-phosphoglycerate?

Answer 15

Phosphoglycerate kinase

Question 16

What enzyme catalyses the reaction of 3-phosphoglycerate into 2 phosphoglycerate?

Answer 16

Phosphoglycerate mutase

Question 17

What enzyme catalyses the reaction of 2-phosphoglycerate into phosphoenol-pyruvate?

Answer 17

Enolase

Question 18

What enzyme catalyses the reaction of phosphoenol-pyruvate into pyruvate?

Answer 18

Pyruvate kinase

Question 19

What sort of reaction is 2-phosphoglycerate > phosphoenol pyruvate?

Answer 19

Dehydration reaction

Question 20

Which reactions in glycolysis are irreversible?

Answer 20

Hexose (glucose > glucose-6-phosphate)
Phosphofructokinase (fructose-6-phosphate > fructose-1,6-bisphosphate)
Pyruvate kinase (phosphoenol pyruvate > pyruvate)

Question 21

In the absense of O2 what happens to pyruvate?

Answer 21

Pyruvate (C=O) is reduced to lactate (C-OH) using NADH.

Pyruvate + NADH + H+ > Lactate + NAD+

Question 22

What is the enzyme that reduces pyruvate to lactate?

Answer 22

Lactate dehydrogenase

Question 23

What is the function of lactate dehydrogenase?

Answer 23

Regeneration of NAD+ using NADH + pyruvate.

Produces lactate

Question 24

Describe the importance of glycolysis in red blood cells.

Answer 24

In erythrocytes there are no mitochondria so aerobic respiration cannot occur nor can the cell use triacylglycerides to generate energy. Hence the erythrocyte can only use glycolysis to release energy.

Question 25

Where would fructose enter the glycolysis pathway?

Answer 25

Fructose is phosphorylated to fructose-1-phosphate. Catalysed by fructokinase

Question 26

Where would galactose enter the glycolysis pathway?

Answer 26

It is converted to glucose-6-phosphate in a 4 step reaction.
Galactose > Galactose-6-phosphate + UTP glucose > UTP-galactose + glucose-6-phosphate
UTP-galactose > UTP-glucose