5.7.4 Glycolysis

Question 1

What does glycolysis involve

Answer 1

• Trapping glucose in the cell by phosphorylating the molecule
• Splitting the glucose molecule in two

Question 2

What does glycolysis result in the production of?

Answer 2

• 2 pyruvate molecules (3C)
• Net gain of 2 ATP
• 2 reduced NAD

Question 3

State and describe the steps of glycolysis

Answer 3

1. Phosphorylation
   Glucose (6C) is phosphorylated by 2ATP to form fructose biphosphate
2. Lysis
   Fructose biphosphate (6C) splits into two molecules of triose phosphate (3C)
3. Oxidation
   Hydrogen is removed from each molecule of triose phosphate and transferred to coenzyme NAD to form 2 reduced NAD
4. Dephosphorylation
   Phosphates are transferred from the intermediate substrate molecules to form 4 ATP through substrate-linked phosphorylation
5. Pyruvate is produced
   The end product of glycolysis which can be used in the next stage of respiration

Question 4

Describe phosphorylation

Answer 4

Glucose (6C) is phosphorylated by 2 ATP to form fructose biphosphate (6C)
Glucose + 2ATP = fructose biphosphate

Question 5

Describe lysis

Answer 5

Fructose biphosphate (6C) splits into two molecules of triose phosphate (3C)
Fructose biphosphate = 2 triose phosphate

Question 6

Describe oxidation

Answer 6

Hydrogen is removed from each molecule of triose phosphate and transferred to coenzyme NAD to form 2 reduced NAD
4H + 2NAD = 2NADH +2H

Question 7

Describe dephosphorylation

Answer 7

Phosphates are transferred from the intermediate substrate molecules to form 4ATP through substrate-linked phosphorylation
4Pi + 4ADP = 4ATP

Question 8

Describe the stage of pyruvate being produced

Answer 8

The end product of glycolysis which can be used in the next stage of respiration
2 Triose phosphate = 2 pyruvate

Question 9

Why is ATP used at the start of glycolysis

Answer 9

ATP is used to make glucose more reactive (it is usually very stable)) and to lower the activation energy of the reaction.