Ch. 9

Question 1

What are the steps of glycolysis (substrates, products and enzymes)?

Answer 1

1. Hexokinase or glucokinase
2. Phosphoglucoisomerase
3. Phosphofructokinase-1
4. Aldolase
5. Triose phosphate isomerase
6. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH)
7. Phosphoglycerate kinase
8. Phosphoglyceromutase
9. Enolase
10. Pyruvate kinase

Question 2

What is reaction 1 of glycolysis?

Answer 2

Hexokinase or glucokinase
- Works via induced-fit mechanism
- Phosphorylation reaction
- ATP hydrolysis
- Mg2+ required

Question 3

What is reaction 2 of glycolysis?

Answer 3

Phosphoclucoisomerase
- Isomerization

Question 4

What is reaction 3 of glycolysis?

Answer 4

Phosphofructokinase-1
- Phosphorylation
- ATP hydrolysis
- Rate-limiting step of entire pathway

Question 5

What is reaction 4 of glycolysis?

Answer 5

Aldolase
- Cleavage
- Uses Schiff base as intermediate

Question 6

What is reaction 5 of glycolysis?

Answer 6

Triose phosphate isomerase
- Isomerization
- 2 G-3-P are used in the subsequent steps of glycolysis
- End of ATP investment stage

Question 7

What is reaction 6 of glycolysis?

Answer 7

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH)
- Phosphoryl group transfer
- Produces 2 NADH (1 per G-3-P)

Question 8

What is reaction 7 of glycolysis?

Answer 8

Phosphoglycerate kinase
- Substrate-level phosphorylation
- Produces 2 ATP - first time ATP made in glycolysis; substrate level phosphorylation

Question 9

What is reaction 8 of glycolysis?

Answer 9

Phosphoglyceromutase
- Phosphoryl shift

Question 10

What is reaction 9 of glycolysis?

Answer 10

Enolase
- Dehydration

Question 11

What is reaction 10 of glycolysis?

Answer 11

Pyruvate kinase
- Substrate-level phosphorylation
- Produces 2 ATP

Question 12

Which stage of glycolysis is ATP investment?

Answer 12

Stage 1 (reactions 1-5)

Question 13

Which stage of glycolysis is ATP production?

Answer 13

Stage 2 (reactions 6-10)

Question 14

What are the differences between stage 1 and 2 of glycolysis?

Answer 14

Stage 1 is ATP investment while Stage 2 is ATP production

Question 15

What are high energy intermediates and why are they important?

Answer 15

• 1,3 bisphosphoglycerate
• phosphoenolpyruvate
• transfer phosphate groups or hydride ions

Question 16

Where does oxidation-reduction take place (step, enzyme, substrates and products)?

Answer 16

6. Glyceraldehyde-3-phosphate
   - 1st high energy intermediate: 1st high energy intermediate: 1,3 biphosphoglycerate (2 per glucose)
   - Generates NADH (2 NADH/glucose)
   - Phosphoryl group transfer

Question 17

Where does NADH go after glycolysis with and without oxygen? Why is this important to have NAD+ again?

Question 18

How does regulation work?

Question 19

How do substrates or molecules before a reaction effect that reaction or subsequent reactions?

Question 20

How do products of immediate reactions or distant reactions change those reactions?

Question 21

How do stage 2 products affect stage 1 of glycolysis for example?

Question 22

What does an allosteric graph look like? What do the 3 curves represent?

Question 23

How is glycolysis regulated?

Question 24

review briefly sugars as shown in the ppt.

Question 25

How do you link to reactions together to obtain a favorable delta G (free energy) and calculate the values?