Key Area 7

Question 1

Which 3 stages are in aerobic respiration?

Answer 1

Glycolysis
Citric Acid Cycle
Electron Transport Chain

Question 2

Which stage is in fermentation?

Answer 2

Glycolysis

Question 3

What are the 3 sections of the mitochondrion?

Answer 3

Outer membrane
Inner membrane
Matrix

Question 4

What is the first stage of respiration?

Answer 4

Glycolysis

Question 5

Where does Glycolysis occur?

Answer 5

Cytoplasm

Question 6

Summarise glycolysis briefly

Answer 6

The breakdown of glucose to pyruvate

Question 7

What 2 sections can glycolysis be split into?

Answer 7

Energy investment Phase

Energy payoff Stage

Question 8

What happens in the Energy investment Phase?

Answer 8

Phosphate is added to glucose ( phosphorylation ) which requires 2 ATP. This occurs twice

Question 9

What happens in the energy payoff stage?

Answer 9

4 ATP is generated, resulting in a net gain of 2 ATP

Enzyme - dehydrogenase removes hydrogen ions and electrons from the intermediate molecules

The hydrogen ions and electrons are passed to coenzyme NAD to form NADH

Question 10

What happens if oxygen is present?

Answer 10

Aerobic respiration can occur

Question 11

What happens if oxygen is not present?

Answer 11

The fermentation pathway takes place and pyrvate is converted to lactate

Question 12

What is the second stage of aerobic respiration?

Answer 12

The citric acid cycle

Question 13

Where does the citric acid cycle occur?

Answer 13

The matrix of the mitochondria

Question 14

What happens to pyruvate at the beginning of the citric acid cycle?

Answer 14

It is transported from the cytoplasm into the matrix in the mitochondria

Question 15

What happens in the Citric Acid Cycle?

Answer 15

Pyruvate is broken down into an acetyl group

This combines with coenzyme A to form acetyl coenzyme A

Carbon Dioxide is produced

More hydrogen ions and electrons are removed by dehydrogenase and from NADH

acetyl coenzyme A joins with oxaloacetate to form citrate

more hydrogen ions and electrons are removed to form NADH

More ATP is produced

citrate is converted back to oxaloacetate

Question 16

What is the Electron Transport Chain?

Answer 16

A group of protein molecules on the inner membrane of the mitochondria

Question 17

What happens during the Electron Transport Chain?

Answer 17

Hydrogen ions and electrons are passed to the ETC by NAD

Electrons are passed along the ETC releasing energy which is used to pump hydrogen ions across the inner mitochondrial membrane

Once they have crossed, they will flow back in the opposite direction through membrane protein - ATP synthase, resulting in the production of more ATP