In 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
Most 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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