unit 5 respiration

Question 1

How is ATP produced? (11)

Answer 1

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;
6. (Carriers) at decreasing energy levels;
7. Energy (lost by electrons) used to produce ATP;
8. From ADP and (inorganic) phosphate;
9. Protons move into intermembrane space;
10. ATP synthase;

Question 2

Describe chemiosmosis. (4)

Answer 2

allows chemiosmosis
1. Electrons transferred down electron transfer chain;
2. Provide energy to transport protons into space between membranes;
chemiosmosis

3. Protons diffuse through membrane/into matrix/through ATP synthase;
4. Energy (from H+ movement) used to combine ADP and phosphate to form ATP

Question 3

Why is there less

ATP produced in anaerobic

respiration? (4)

Answer 3

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 4

Describe anaerobic respiration in

animals. (5)

Answer 4

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

Question 5

Describe oxidative phosphorylation (6)

Answer 5

1. reduced NAD and FAD transport electrons to the electron transport chain
2. electrons travel along the electron transport chain releasing energy
3. this energy is used to power the proton pumps which pump the protons into intermembrane space
4. the protons move down a gradient through the ATP synthase
5. ATP is produced through a condensation reaction between ADP+PI
6. electrons are removed from the carrier by O2 because it is the final electron acceptor, which then forms H2O

Question 6

describe the Krebs cycle

Answer 6

1. ATP by substrate level phosphorylation
2. Reduced coenzyme
3. CO2 from decarboxylation

Question 7

describe the link reaction

Answer 7

1. Oxidation of Pyruvate to acetate (1xCO2 2xH 1x reduced NAD)
2. Acetate combines with coenzyme A to form acetylcoenzyme A

Question 8

explain why a reduction the krebs cycle reduces the production of ATP (3)

Answer 8

1. less reduced NAD and FAD
2. less electrons transported to electron transport chain by the reduced FAD and NAD
3. less electrons travel along electron transport chain releasing energy
4. less protons diffusing down a gradient through ATP synthase

Question 9

explain why a reduction in the krebs cycle reduces the uptake of oxygen

Answer 9

1. less reduced NAD and FAD
2. less electrons transported to electron transport chain by the reduced FAD and NAD
3. less electrons travel along electron transport chain releasing energy
4. less O2 needed to remove electrons from electron transport chain as their are less electrons
5. O2 is the final electron acceptor

Question 10

Describe glycolysis

Answer 10

1. Glucose is phosphorylated to GP by 2xATP
2. GP splits into 2x triose phosphate
3. Triose phosphate is oxidised to 2x pyruvate (2x reduced NAD, 2xATP per glucose)