3.5.2 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;
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 2

Describe chemiosmosis. (4)

Answer 2

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 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 NADH;
3. Regenerates NAD;
4. NAD allows glycolysis to continue;
5. Can still release energy from ATP when no oxygen;

Question 5

Describe glycolysis in respiration

Answer 5

• glucose phosphorylated to hexose biphosphate by ATP
• hexose biphosphate split into two Triose phosphate
• triose phosphate oxidised to pyruvate
• this reduces NAD to reduced NAD
• ATP produced

Question 6

Describe the link reaction in respiration

Answer 6

• pyruvate decarboxylated
• CO2 removed
• pyruvate oxidised to produce acetate and reduce NAD
• acetate combines with coenzyme A to form acetyl coenzyme A
• occurs twice per glucose molecule

Question 7

Describe the krebs cycle in respiration

Answer 7

• acetyl coenzyme a combines with 4C molecule
• forms 6C molecule
• 6C decarboxylated and dehydrogenated until 4C molecule reformed
• produces reduced NAD &FAD a
• ATP produced