6 (a) Fig. 6.1 shows a transmission electron micrograph of a section through a mitochondrion. [Figure 6.1] Fig. 6.1 Table 6.1 shows some structures and compounds involved in aerobic respiration. Use letter P or letter Q from Fig. 6.1 to complete Table 6.1 to show the location of the structures and where the compounds are used. [Table 6.1] Table 6.1 | compound or structure | location | | :-------------------- | :------- | | ATP synthase | | | acetyl CoA | | | phospholipid bilayer | | | oxaloacetate | |

1. (a)Fig. 6.1 shows a transmission electron micrograph of a section through a mitochondrion. [Figure 6.1] Fig. 6.1 Table 6.1 shows some structures and compounds involved in aerobic respiration. Use letter P or letter Q from Fig. 6.1 to complete Table 6.1 to show the location of the structures and where the compounds are used. [Table 6.1] Table 6.1 | compound or structure | location | | :-------------------- | :------- | | ATP synthase | | | acetyl CoA | | | phospholipid bilayer | | | oxaloacetate | |[3]
2. (b)(i)The number of mitochondria differs from cell to cell. Cells also vary in size and volume. Table 6.2 shows the mean number of mitochondria per cell, the mean cell volume and the mean number of mitochondria per µm³ of three types of mammalian cells. [Table 6.2] Table 6.2 | cell type | mean number of mitochondria per cell | mean cell volume /μm³ | mean number of mitochondria per µm³ | | :-------- | :----------------------------------- | :-------------------- | :------------------------------------ | | fat cell | 100 | 600000 | 0.17 × 10-3 | | heart cell| 2000 | 45000 | 44.44 × 10-3 | | liver cell| 2000 | 125000 | | Calculate the mean number of mitochondria per µm³ for the liver cell. Write your answer in Table 6.2.[1]
3. (b)(ii)Suggest reasons for the difference in mean number of mitochondria per um³ between the fat cell and the heart cell.[2]
4. (b)(iii)Suggest why it is difficult to compare the ability of the three types of cell to respire aerobically, based only on the mean number of mitochondria per cell.[1]

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