Respiration

Question 1

Describe the process of glycolysis (4)

Answer 1

• phosphorylation of glucose using ATP
• oxidation of triose phosphate to pyruvate
• NAD is reduced
• net gain of ATP

Question 2

Malonate inhibits a reaction in the kerbs cycle
Explain why it would decrease the uptake of oxygen in a respiring cell (2)

Answer 2

• fewer electrons removed and passed to electron transfer chain
• oxygen is the final electron acceptor

Question 3

Aerobic respiration produces more ATP per molecule of glucose than anaerobic respiration. Explain why (2)

Answer 3

• oxygen is final electron acceptor
• in aerobic respiration there is oxidative phosphorylation
• in anaerobic respiration only glycolysis occurs

Question 4

In muscles, pyruvate is converted to lactate during exercise.

Explain why converting pyruvate to lactate allows the continued production
of ATP by anaerobic respiration (2)

Answer 4

1. Regenerates NAD
2. (So) glycolysis continues;

Question 5

describe how ATP is made in mitochondria (6)

Answer 5

   1.    ATP produced in Krebs cycle;

2.      Krebs cycle / link reaction produces reduced reduced NAD

3.      Electrons released from reduced NAD

4.  electrons pass along carriers through series of redox reactions;

5.      Energy released;

6.      ADP / ADP + Pi;
7.      Protons move into inter membrane space;
8.      ATP synthase;

Question 6

Plants produce ATP during photosynthesis. They also produce ATP during respiration.
Explain why it is important for plants to produce ATP during respiration in addition to during photosynthesis (5)

Answer 6

1.      In the dark no ATP production from photosynthesis;

2.      Some tissues unable to photosynthesise / produce ATP;

3.      ATP cannot be moved from cell to cell;

4.      Plant uses more ATP than produced in photosynthesis;

5.      ATP for active transport

Question 7

areas of tropical forest are still found on islands. concentration of carbon dioxide in air of these forests changes over period of 24 hours and at different heights above ground.

Use knowledge of photosynthesis and respiration to describe and explain how the concentration of carbon dioxide in the air changes:

*        over a period of 24 hours

*        at different heights above ground.

Answer 7

    1.     High concentration of carbon dioxide linked with respiration at  night

2.      No photosynthesis in night
3.      In light, net uptake of carbon dioxide / use more carbon dioxide than produced
4.      Decrease in carbon dioxide concentration with height; More carbon dioxide absorbed higher up; more photosynthesis
5.      At ground level  less photosynthesis