Practise how carbon, coenzymes and ATP move through aerobic respiration, compare fermentation and investigate respiration using indicators or a respirometer.
Oxygen is needed for aerobic respiration in cells.
In eukaryotic cells, the mitochondrion is the organelle used for aerobic respiration.
Fig. 1.1 shows a transmission electron micrograph of a mitochondrion.
Fig. 1.1
Table 1.1 lists the four stages of aerobic respiration.
With reference to Fig. 1.1, complete Table 1.1 using the letters A-D to show where each stage occurs.
Each letter may be used once, more than once or not at all.
Table 1.1
In anaerobic conditions, no ATP can be synthesised by oxidative phosphorylation because the process stops.
Explain why ATP synthesis by oxidative phosphorylation stops in anaerobic conditions.
Up to 60\% of the ATP that is produced in cancer cells comes from lactate fermentation of glucose, even though oxygen is present.
Scientists are developing cancer treatments to inhibit the enzyme that catalyses the last step of lactate fermentation.
Explain how the inhibition of this enzyme reduces the production of ATP in cancer cells.
Glycolysis is a biochemical pathway that occurs in the cytoplasm of cells.
In glycolysis, a molecule of glucose is metabolised to two molecules of pyruvate. The process is outlined in Fig. 1.1.
Fig. 1.1
Explain why glucose is phosphorylated at the beginning of glycolysis.
Suggest one use of the reduced NAD that is produced in glycolysis.
Pyruvate can enter the mitochondrion by active transport.
Describe the main conditions that are required for pyruvate to enter the mitochondrion by active transport.
Pyruvate is involved in the link reaction in the matrix of the mitochondrion.
Describe the link reaction.