1.7

Question 1

What happens in the Energy Investment Stage

Answer 1

ATP is used to phosphorylate the glucose and the intermediates
2ATP are used up per glucose molecule

Question 2

What happens in the Energy Payoff Stage

Answer 2

4 ATP are produced per glucose molecule so there is a net gain of 2ATP
The dehydrogenase enzyme removes Hydrogen ions AND electrons and passes them to the coenzyme NAD to form NADH which travels to the 3rd stage – the electron transport chain
This occurs in both glycolysis and the citric acid cycle

Question 3

Where do the 3 stages respiration occur

Answer 3

1 - Glycolysis - in the cytoplasm (doesn’t require oxygen)
2 - Citric Acid Cycle - in the matrix of the mitochondria (requires oxygen)
3 - Electron Transport Chain - in the inner membrane of the mitochondria

Question 4

What happens in the Citric Acid Cycle

Answer 4

In aerobic conditions pyruvate is broken down to an acetyl group that combines with coenzyme A, forming Acetyl coenzyme A.
In the citric acid cycle the acetyl group from acetyl coenzyme A combines with Oxaloacetate to form citrate.
During a series of enzyme-controlled steps, citrate is converted back in to Oxaloacetate which results in the generation of ATP and the release of Carbon Dioxide.
Dehydrogenase Enzymes remove hydrogen ions and electrons and pass them to the coenzyme NAD forming NADH.
NADH travels to the electron transport chain on the inner mitochondrial membrane.
This occurs in both Glycolysis and the Citric Acid Cycle

Question 5

What happens in the Electron Transport Chain

Answer 5

Electrons (from NADH) are passed along the electron transport chain releasing energy.
This energy allows hydrogen ions to be pumped across the inner mitochondrial membrane.
The flow of the Hydrogen ions back through the membrane protein ATP Synthase results in the production of ATP.
Finally, hydrogen ions and electrons combine with oxygen to form water.
ATP is used to transfer energy to cellular processes which require energy