Lecture 24 - Glucose as a fuel molecule 2

Question 1

What is the main purpose of glycolysis

Answer 1

A conversion of one molecule of glucose into two molecules of pyruvate, captain energy in the form of ATP and NADH

Question 2

What are the two phases of glycolysis

Answer 2

1. Energy investment phase
2. Energy payoff phase

Question 3

Net gain from glycolysis

Answer 3

is 2 ATP and 2 NADH

Question 4

How is glucose activated during glycolysis

Answer 4

Through two ATP consuming reactions catalysed by 1. hexokinase and 3. phosphofructokinase

Question 5

What reaction does hexokinase catalyse in glycolysis

Answer 5

The phosphorylation of glucose to glucose-6-phosphate using ATP. ATP turns into ADP by giving away its phosphate and releasing energy

Question 6

Why is energy input required in the first steps if glycolysis

Answer 6

To activate glucose, making it easier to split and capture energy in later steps

Question 7

What happens to glucose-6-phosphate in the second step of glycolysis

Answer 7

It is isomerised to fructose-6-phosphate by glucose phosphate isomerase

Question 8

What does photofructokinase do in glucose

Answer 8

It catalyses the phosphorylation of fructose-6-phostphate to fructose-1,6-biphosphate using ATP

Question 9

Key enzyme that is responsible for splitting fructose

Answer 9

Aldose - splitting fructose into DHAP and G3P

Question 10

What is the significance of G3P

Answer 10

It enters the energy payoff phase of glycolysis, where ATP and NADH are produce

Question 11

How is NADH generated in glycolysis

Answer 11

Through the oxidation of G3P to 1,3-BPG by G3P dehydrogenase, with NAD+ being reduced to NADH

Question 12

What is substrate level phosphorylation

Answer 12

A direct transfer of a phosphate group from a high-energy substrate to ADP to form ATP

Question 13

what reactions in glycolysis involve substrate level phosphorylation

Answer 13

1. Conversion of 1,3-BPG to 3-phospholglycerate
2. Conversion of phosphoenolpyruvate ti pyruvate

Question 14

what happens to pyruvate under aerobic conditions

Answer 14

It is converted into acetyl CoA, which enters the citric acid cycle

Question 15

What happens to pyruvet under anaerobic conditions

Answer 15

It is converted in into lactate to regenerate NAD+

Question 16

Why is lactate produce under anaerobic conditions

Answer 16

To regenerate NAD+ so that glycolysis can continue in the absence of oxygen

Question 17

How does the chemical arsenic affect glycolysis

Answer 17

Arsenate can replace phosphate in the glycolyic pathway, preventing ATP synthesis and poisoning the pathway

Question 18

What coenzyme is essential for glycolysis and other redox reactions

Answer 18

NAD+ derived from vitamin B3

Question 19

What is Gibbs energy and its relevance in glycolysis

Answer 19

In glycolysis unfavourable reactions are coupled with ATP hydrolysis to make them favourable

Question 20

What are the two main types of reactions involved in ATP synthesis

Answer 20

1. substrate level phosphorylation
2. Oxidative phosphorylation

Question 21

what happens during pyruvate dehydrogenase reaction

Answer 21

Pyruvate us oxidised to acetate CoA - aerobic and NADH is produced as well well as CO2 is released

Question 22

What is the significance of PEP in glycolysis

Answer 22

PEP is high energy compound that donates phosphate to ADP, forming ATP and pyruvate