Glycolysis

Question 1

Where does glycolysis take place?

Answer 1

In the cytoplasm

Question 2

What are the products of glycolysis?

Answer 2

2 pyruvate
2 NADH
2 ATP

Question 3

Glucose—-> ?

What enzyme?

Answer 3

Glucose —-> glucose 6 phosphate
Hexokinase
ATP—-> ADP

Question 4

In the liver, what is the enzyme called converting glucose to glucose 6 phosphate?

Answer 4

Glucokinase

Question 5

Glucose-6-phosphate—-> ?

Enzymes?

Answer 5

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

Phosphohexose isomerase

Question 6

Fructose-6-phosphate—-> ?

Enzymes?

Answer 6

Fructose-6-phosphate—->fructose-1,6-bisphosphate
PFK-1 (phosphofructokinase-1)
ATP—->ADP

Question 7

What can fructose-1,6-bisphosphate become?

Answer 7

Dihydroxyacetone phosphate

3-phosphoglyceraldehyde

Question 8

Fructose-1,6-bisphosphate —> dihydroxyacetone phosphate —> 3-phosphoglyceraldehyde
Enzymes for each step?

Answer 8

Aldolase

Triose phosphate isomerase

Question 9

Fructose-1,6-bisphosphate ——> 3-phosphoglyceraldehyde?

Enzyme?

Answer 9

Fructose bisphosphate aldolase

Question 10

3-phosphoglyceraldehyde —-> ?

Enzymes?

Answer 10

3-phosphoglyceraldehyde —-> 1,3-bisphosphoglycerate
Glyceraldehyde-3-phosphate dehydrogenase
NAD+ —> NADH

Question 11

1,3-bisphosphoglycerate —-> ?

Enzymes?

Answer 11

1,3-bisphosphoglycerate —-> 3-phosphoglycerate
Phosphoglycerate kinase
ADP—> ATP

Question 12

3-phosphoglycerate —-> ?

Enzyme?

Answer 12

3-phosphoglycerate —-> 2 phosphoglycerate

Phosphoglycerate mutase

Question 13

2 phosphoglycerate —-> ?

Enzyme?

Answer 13

2 phosphoglycerate —-> phosphoenolpyruvate

Enolase

Question 14

phosphoenolpyruvate —-> ?

Enzyme?

Answer 14

phosphoenolpyruvate —-> pyruvate
Pyruvate kinase
ADP—-> ATP

Question 15

Where does pyruvate go to?

Answer 15

Lactate (anaerobic)

Krebs cycle (aerobic)

Question 16

Which 2 enzymes are regulated?

Answer 16

Hexokinase

PFK-1

Question 17

What is Hexokinase activity controlled by?

Answer 17

Controlled by glucose-6-phosphate
Reversible reaction
More product, slower rate of reaction

Question 18

What is the main regulator/rate limiting step of glycolysis?

Answer 18

PFK-1

Question 19

What is PFK-1 effected by?

Answer 19

Allosterically - not affected by main active site

AMP (adenosine monophosphate)

Question 20

How does AMP effect PFK-1?

Answer 20

It is an allosteric activator (modifies the AS of the enzyme so affinity for substrate increases)
Increased AMP = increased PFK-1 action = increased affinity for fructose 6 phosphate

Question 21

How does ATP affect PFK-1?

Answer 21

ATP is an allosteric inhibitor (decreases affinity for substrate to bind)
Inhibited by ATP
Increased ATP = decreased PFK-1
Decreased ATP = increased PFK-1

Question 22

Which 2 steps produce ATP?

Answer 22

1,3-bisphosphoglycerate —-> 3-Phosphoglycerate

Phosphoenolpyruvate — > pyruvate

Question 23

What does insulin affect and how?

Answer 23

Insulin increases rate of glycolysis (affects PFK-1 indirectly)

Question 24

Is glycolysis aerobic or anaerobic?

Answer 24

Anaerobic (doesn’t need O2)

Question 25

What does anaerobic resp produce?

Answer 25

Produces lactate (toxic) and NAD+ (so glycolysis can continue) and a little ATP