Glycolysis 17.1

Question 1

Where does glycolysis take place?

Answer 1

In the cytoplasm of the cell

Question 2

Is it anaerobic or aerobic?

Answer 2

Anaerobic

Question 3

List the 4 steps of glycolysis

Answer 3

• Phosphorylation
• Lysis
• Phosphorylation
• Dehydrogenation and formation of ATP

Question 4

Phosphorylation 1

Answer 4

2 molecules of ATP are required. They are hydrolysed and the 2 inorganic phosphates bind to the glucose to make hexose bisphosphate

Question 5

Lysis

Answer 5

hexose bisphosphate is unstable so will split into 2 triose phosphate (TP) molecules

Question 6

Phosphorylation 2

Answer 6

A phosphate group will add to each triose phosphate to make triose diphosphate. The phosphate groups come from free-floating inorganic phosphate ions in the cytoplasm

Question 7

Dehydrogenation + ATP formation

Answer 7

• Firstly the NAD+ coenzymes will oxidise the triose bisphosphate to remove hydrogens and they will become reduced NAD (NADH). This is called dehydrogenation
• 2 ADP molecules will accept all the phosphates on the triose phosphates and form 4 ATP molecules by substrate phosphorylation. The product remaining is pyruvate.

Question 8

What is substrate-level phosphorylation?

Answer 8

When a phosphate group is removed from a molecule and added to another molecule to make ATP. It doesn’t involve the electron transport chain. In this example, the phosphate was removed from the triose bisphosphate and added to the ADP.

Question 9

What is the net produce of glycolysis?

Answer 9

Per glucose molecule

• 4 ATP used, 2 ATP created so 2 ATP net
• 2 NADHs formed
• 2 pyruvate molecules formed