1a
2 marks
2 marksIn cells, energy can be released from substrates by anaerobic and aerobic respiration.
Most eukaryotic cells can respire anaerobically.
(i)
Which of the following describes a step in the process of anaerobic respiration?
(1)
| ☐ | A | decarboxylation of lactate | |
| ☐ | B | phosphorylation of hexoses | |
| ☐ | C | oxidation of pyruvate | |
| ☐ | D | removal of phosphate groups from glucose |
(ii)
What happens to the lactate concentration during a period of anaerobic respiration?
(1)
| ☐ | A | decreases, causing a decrease in blood pH | |
| ☐ | B | decreases, causing an increase in blood pH | |
| ☐ | C | increases, causing a decrease in blood pH | |
| ☐ | D | increases, causing an increase in blood pH |
1b8 marks
8 marksMost eukaryotic cells are also able to respire aerobically.
(i)
How do respiratory substrates enter the Krebs cycle?
(1)
| ☐ | A | as molecules containing 2 carbon atoms produced by the link reaction | |
| ☐ | B | as molecules containing 3 carbon atoms produced by the link reaction | |
| ☐ | C | as molecules containing 2 carbon atoms produced by RUBISCO | |
| ☐ | D | as molecules containing 3 carbon atoms produced by RUBISCO |
(ii)
Draw a diagram of a mitochondrion.
Label only the part of the mitochondrion where the Krebs cycle occurs.
(2)
(iii)
Describe the role of chemiosmosis in the synthesis of ATP.
(5)
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