Glycolysis

Question 1

What is the net amount of ATP produced in glycolysis

Answer 1

2 ATP

Question 2

In glycolysis glucose is converted to…

Answer 2

2 Pyruvate molecules

Question 3

Where does glycolysis take place

Answer 3

Cytoplasm

Question 4

3 main steps of glycolysis

Answer 4

1)Investment phase – Use 2 ATP to phosphorylate Glucose to Glucose-3P and Fructose 1,6-BP

2) Cleavage- break Glucose (6-carbon sugar) into 2 Glyceraldehyde-3-P (3-carbon chains)

3) Generation phase – Produce 2 Pyruvate, 4 ATP, 2 NADH

Question 5

Investment phase

Answer 5

1. Phosphorylation (irreversible): A phosphate group is
   transferred from ATP to glucose by
   hexokinase/glucokinase, making Glucose-6-
   phosphate
2. Isomerization: G6P converts to Fructose-6-
   phosphate isomer
3. Phosphorylation (irreversible): A phosphate group is
   transferred from ATP to F6P by PFK making
   Fructose 1,6-biphosphate. PFK is inhibited
   allosterically by high ATP levels

Question 6

Cleavage phase

Answer 6

4. Cleavage: Fructose 1,6-biphosphate
   is cleaved by aldolase to form two 3
   Carbon isomers, DHAP and
   Glyceraldehyde 3-phosphate (G3P)
5. Isomerization: DHAP is converted to
   G3P. Only G3P continues to next
   steps

Question 7

Generation phase

Answer 7

6. Oxidation & Phosphorylation: G3P is oxidized and
   phosphorylated to 1,3-biphosphoglycerate. NAD+ is
   reduced to NADH.
7. Phosphate transfer: Phosphate is transferred from
   1,3BPG to ADP, forming 3-phophoglycerate. ATP is
   produced
8. Isomerization: 3-phosphoglycerate isomerizes to 2-
   phosphoglycerate
9. Dehydration: 2-phosphoglycerate lose water to
   phosphoenolpyruvate (PEP)
10. Phosphate transfer (irreversible): Pyruvate Kinase
    transfer phosphate group from PEP to ADP, producing
    pyruvate & ATP

Generation phase: 2 NADHs + 4 ATP

Net gain: 2 NADH + 2 ATP + 2 pyruvate (each glucose)

Question 8

What is the rate limiting step

Answer 8

Phosphorylation - fructose 6-phosphate to fructose 1,6-bisphosphate

Question 9

What is the rate limiting enzyme

Answer 9

PFK-1

Question 10

Anaerobic glycolysis

Answer 10

Question 11

Inhibitors of PFK

Answer 11

-Citrate
-ATP
-Lactic acid

Question 12

How does PFK-2 increase rate of glycolysis

Answer 12

produces fructose 2,6 bisphosphate which activate PFK-1 - the rate limiting step - so the overall reaction rate increases

Question 13

what happens to PFK-2 when blood glucose 1.increases
and
2.decreases

Answer 13

1. insulin is produced which increases PFK-2
2. glucagon is produced which decreases PFK-2

Question 15

Summary of glycolysis

Answer 15