Glycolysis

Question 1

What is the overall reaction of glycolysis?

Answer 1

Glucose —-> pyruvate

Question 2

What are the net products of glycolysis?

Answer 2

• Pyruvate x2
• NADH x2
• ATP x2

Question 3

What are the two phases of glycolysis?

Answer 3

1. Preparation phase (Glucose - G3P)

2. Pay-off phases (1,3-BPG - pyruvate)

Question 4

What is the significance that G6P is a negatively charged molecule?

Answer 4

It traps glucose within the cell

Question 5

Reaction 1: what is it?

What does it require?

Answer 5

Glucose —> Glucose-6-phosphate
ATP
Hexokinase

Question 6

In which form is the ATP used in reaction 1 supplied?

Answer 6

MgATP

Question 7

Reaction 2: what is it?

What does it require?

Answer 7

Glucose-6-phosphate —-> Fructose-6-phosphate

Phosphoglucose isomerase

Question 8

Reaction 3: what is it?

What does it require?

Answer 8

Fructose-6-phosphate —> Fructose-1, 6-bisphosphate
Phosphofructokinase-1
Uses ATP

Question 9

Reaction 4: What is it?

What does it require?

Answer 9

Fructose-1, 6-bisphosphate —-> Glyceraldehyde-3-phophate + Dihydroxyacetone glycerate
Requires aldolase

Question 10

Reaction 5: What is it?

What does it require?

Answer 10

Dihydroxyacetone glycerate —-> Glyceraldehyde-3-phophate

Requires triose phosphate isomerase

Question 11

Reaction 6: What is it?

What does it require?

Answer 11

Glyceraldehyde-3-phophate —-> 1, 3-bisphosphoglycerate
Requires glyceraldehyde-3-phosphate dehydrogenase
Produces 2 NADH

Question 12

Reaction 7: What is it?

What does it require?

Answer 12

1, 3-bisphosphoglycerate —-> 3-phosphoglycerate
Requires phosphoglycerate kinase
Produces 2 ATP

Question 13

Reaction 8: What is it?

What does it require?

Answer 13

3-phosphoglycerate —-> 2-phosphoglycerate

Requires phosphoglyceromutase

Question 14

Reaction 9: What is it?

What does it require?

Answer 14

2-phosphoglycerate ——>phosphoenol pyruvate
Requires enolase
Produces H2O

Question 15

Reaction 10: What is it?

What does it require?

Answer 15

Phosphoenol pyruvate —-> pyruvate
Requires pyruvate kinase
Produces 2 ATP

Question 16

Which is the only reaction involving ATP that is reversible?

Answer 16

Reaction 7: 1, 3-BPG —> 3-PG

Question 17

Why is arsenate poisonous?

Answer 17

Practically identical to phosphate so substitutes it meaning a different product is formed and an ATP-producing step is skipped

Question 18

At which reaction does arsenate substitute phosphate?

Answer 18

At reaction 6 to form 1-arseno-3-phosphoglycerate

Question 19

In anaerobic conditions, what reaction does pyruvate undergo?

Answer 19

Pyruvate —–> lactate
catalysed by lactate dehydrogenase
produces NAD

Question 20

At what three points is glycolysis regulated?

Answer 20

• PFK-1
• Hexokinase
• Pyruvate kinase

Question 21

How is hexokinase regulated?

Answer 21

Regulated by glucose-6-phosphate

Question 22

Why is regulation at hexokinase not a major point?

Answer 22

Because glucose can also be converted to glycogen

Question 23

How is pyruvate kinase regulated?

Answer 23

Inhibited by ATP and acetyl CoA

Activated by fructose-1, 6-bisphosphate

Question 24

What is pyruvate kinase activated by?

Answer 24

Fructose-1, 6-bisphosphate

Question 25

What is pyruvate kinase inhibited by?

Answer 25

ATP and acetly CoA

Question 26

How is phosphofructokinase-1 regulated?

Answer 26

Inhibited by ATP | Inhibition is reversed by AMP

Question 27

How is PFK-1 inhibited?

Answer 27

Inhibited by ATP as at high levels, ATP allosterically inhibits PFK-1 thus lowering the affinity of PFK-1 for fructose-6-phosphate

Question 28

How is the inhibition of PFK-1 reversed?

Answer 28

Inhibition is reversed by AMP

Question 29

What is Tarui disease?

Answer 29

A disease that prevents the conversion of fructose-6-phosphate ---> fructose-1, 6-phosphate

Question 30

Give examples of symptoms of Tarui disease?

Answer 30

Muscle fatigue and cramping

Question 31

How many forms of hexokinase are there?

Answer 31

Four. I to IV

Question 32

Which forms of hexokinase are known as glucokinase?

Answer 32

I and IV

Question 33

Where can glucokinase be found?

Answer 33

In hepatocytes

Question 34

Difference between hexokinase and glucokinase

Answer 34

Hexokinase works at maximum rate at minimum levels of glucose Glucokinase doesn't reach maximum rate until [glucose] is much higher

Question 35

What does glucokinase do?

Answer 35

Helps the liver to buffer blood glucose

Question 36

Hexokinase II

Answer 36

Molecule in open configuration when no glucose molecule is bound After binding --> closed configuration

Question 37

Per glucose molecule, what is the net yield of glycolysis?

Answer 37

2xPyruvate, 2xNADH, 2xATP