Lecture 24 - Glycolysis

Question 1

What is the driving force for this reaction?

Answer 1

ATP hydrolysis

Question 2

Describe this reaction:

Answer 2

1st activation of glucose, phosphate group added

Question 3

What type of reaction is this and how is it driven forwards?

Answer 3

Rearrangement, driven forwards when not under standard conditions.

Question 4

Describe this reaction:

Answer 4

2nd activation of glucose, coupled to ATP hydrolysis

Question 5

What is the result of this reaction?

Answer 5

G-3-P, 2 x 3C and 1P molecule

Question 6

What drives the rearrangement of dihydroxyacetone phosphate to G-3-P?

Answer 6

Low conc. of G-3-P

Question 7

What powers the addition of phosphate from solution?

Answer 7

Oxidation of G-3-P, no ATP required

Question 8

What is the role of NAD+?

Answer 8

Reduction to NADH provides oxidising power

Question 9

What feature of 1,3-BPG allows this reaction?

Answer 9

1st carbon is very reactive, allows phosphate to be easily removed.

Question 10

What type of reaction is this and where is the energy coming from?

Answer 10

1st Substrate level phosphorylation, energy is released when phosphate cleaved and used for SLP, ATP released

Question 11

What type of reactions are these and what is their purpose?

Answer 11

Rearrangement, gets molecule into a form that enables following reactions

Question 12

What is the purpose of this reaction?

Answer 12

2nd Substrate level phosphorylation, energy captured in ATP

Question 13

Where does aerobic oxidation occur?

Answer 13

Mitochondrial matrix

Question 14

What is the role of NAD+ in aerobic oxidation?

Answer 14

Captures energy which is then used to add CoA to 2C chain to produce acetyl-CoA

Question 15

What does the formation of lactate allow for?

Answer 15

Regeneration of NAD+, which means sufficient NAD+ for G-3-P dehydrogenase reaction and glycolysis can continue when no O2 present.

Question 16

Why is the oxidation of glyceraldehyde-3-phosphate essential for glycolysis to make and ATP profit?

Answer 16

Results in 1,3-BPG which has a high energy phosphate bond, Conserves energy in NADH which is used in oxidative phosphorylation to produce ATP

Question 17

What is substrate level phosphorylation?

Answer 17

Direct use of energy from a substrate molecule to drive synthesis of ATP. One way is through cleavage of phosphate ester bond.

Question 18

What are the two types of reactions that involve energy conversions?

Answer 18

1. Those involving ATP and ADP
2. Redox reactions, fuel molecules are oxidised

Question 19

What is this molecule?

Answer 19

NAD

Question 20

What is NAD derived from?

Answer 20

Niacin, (vitamin B3)

Question 21

What does NADH (reduced form) carry?

Answer 21

2 x e-
1 x H+

Question 22

NAD undergoes a _________ reduction.

Answer 22

two-electron (accepts two reducing equivalents).

Question 23

What is the overall reaction for glycolysis?

Answer 23

Question 24

What is coenzyme A (Co-A) derived from?

Answer 24

Pantothenic acid (vitamin B5)

Question 25

What does Co-A carry?

Answer 25

acyl groups, (2C - long C chains)

Question 26

What are the two forms of Co-A?

Answer 26

Free coenzyme: Co-ASH
Acyl Group attached: Acyl-CoA (different to acetyl-CoA)

Question 27

What stage glycolysis does arsenic effect?

Answer 27

1st Substrate level phosphorylation, so no energy captured and no net gain of APT

Question 28

If arsenic present which molecule would be changed?

Answer 28

1,3-BPG for 1-arseno-3-phosphateglycerate. Arsenate substitutes for phosphate.

Question 29

Why does arsenate prevent ATP profit being made?

Answer 29

Arsenate substitutes for phosphate on 1,3-BPG so no high energy bond to cleave, therefore no energy released, and no ATP made