3.5.2 Respiration

Question 1

What is the purpose of respiration

Answer 1

To produce ATP

Question 2

Where does glycolysis occur

Answer 2

In the cytoplasm

Question 3

Is glycolysis aerobic or anaerobic

Answer 3

Anaerobic

Question 4

What is the first step of glycolysis

Answer 4

Phosphorylation of glucose to glucose phosphate using ATP

Question 5

What is produced after glucose phosphate in glycolysis

Answer 5

Triose phosphate

Question 6

What happens to triose phosphate in glycolysis

Answer 6

It is oxidised to pyruvate

Question 7

What are the products of glycolysis

Answer 7

Net gain of ATP and reduced NAD and pyruvate

Question 8

What happens to pyruvate in anaerobic respiration

Answer 8

Converted to ethanol or lactate using reduced NAD

Question 9

Why is oxidised NAD important in anaerobic respiration

Answer 9

It can be reused in further glycolysis

Question 10

How does pyruvate enter mitochondria in aerobic respiration

Answer 10

By active transport into the mitochondrial matrix

Question 11

What happens to pyruvate in the link reaction

Answer 11

It is oxidised to acetate producing reduced NAD

Question 12

What does acetate combine with in the link reaction

Answer 12

Coenzyme A

Question 13

What is produced when acetate and coenzyme A combine

Answer 13

Acetylcoenzyme A

Question 14

What does acetylcoenzyme A react with in the Krebs cycle

Answer 14

A four carbon molecule

Question 15

What is released when acetylcoenzyme A enters the Krebs cycle

Answer 15

Coenzyme A

Question 16

What does the Krebs cycle produce

Answer 16

A six carbon molecule that enters a series of oxidation reduction reactions

Question 17

What are the products of the Krebs cycle

Answer 17

Reduced coenzymes and ATP by substrate level phosphorylation and carbon dioxide

Question 18

What is oxidative phosphorylation

Answer 18

The synthesis of ATP using energy released by electrons down the electron transfer chain

Question 19

What happens as electrons pass down the electron transfer chain

Answer 19

Protons are transferred across the inner mitochondrial membrane

Question 20

What catalyses the synthesis of ATP in oxidative phosphorylation

Answer 20

ATP synthase embedded in the inner mitochondrial membrane

Question 21

What is the name of the theory that explains ATP synthesis in mitochondria

Answer 21

Chemiosmotic theory

Question 22

What other molecules can act as respiratory substrates

Answer 22

Breakdown products of lipids and amino acids

Question 23

How do lipids and amino acids enter the respiration pathway

Answer 23

They enter the Krebs cycle

Question 24

How is ATP produced? (11)

Answer 24

1. ATP produced in glycolysis;
2. Involving the oxidation of glucose/TP to pyruvate;
3. ATP production/ Substrate level phosphorylation directly from Krebs cycle;
4. Glycolysis/Krebs cycle produce reduced NAD/FAD;
5. Reduced NAD/FAD transfer electrons to electron transport chain;
6. Electrons transferred down a chain of carriers;
7. (Carriers) at decreasing energy levels;
8. Energy (lost by electrons) used to produce ATP;
9. From ADP and (inorganic) phosphate;
10. Protons move into intermembrane space;
11. ATP synthase;

Question 25

Describe chemiosmosis. (4)

Answer 25

1. Electrons transferred down electron transfer chain;
2. Provide energy to transport protons into space between membranes;
3. Protons diffuse/pass back, through membrane/into matrix/through ATP synthase;
4. Energy (from H+ movement) used to combine ADP and phosphate to form ATP

Question 26

Why is there less ATP produced in anaerobic
respiration? (4)

Answer 26

1. ATP formed as electrons pass along transport chain;
2. Oxygen is terminal electron acceptor
3. Forms H2O;
4. Electrons cannot be passed along electron transport chain if no O2 to accept them;

Question 27

Describe anaerobic respiration in
animals. (5)

Answer 27

1. Forms lactate;
2. Use of NADH;
3. Regenerates NAD;
4. NAD allows glycolysis to continue;
5. Can still release energy from ATP when no oxygen;