Use Table 1 to identify the three different amino acids used to make the polypeptide shown in Figure 1.

Left amino acid

Middle amino acid

Right amino acid

Table 2 shows three statements and names of four biological molecules.

Put a tick (✓) in each box where the statement is true for the biological molecule.

Figure 2 represents the structure of adult human haemoglobin.

The number of amino acids in the beta chains in Figure 2 is 3.546% greater than in the alpha chains. Each alpha chain contains 141 amino acids.

Calculate how many amino acids there are in total in the haemoglobin molecule shown in Figure 2. Give your answer to the nearest whole number.

Answer ______________ amino acids

When a substance called BPG binds to haemoglobin, it reduces the affinity of haemoglobin for oxygen.

Figure 3 shows an oxyhaemoglobin dissociation curve for haemoglobin in normal conditions.

Sketch a curve on Figure 3 to show the oxyhaemoglobin dissociation curve for haemoglobin when BPG binds to it.

Suggest and explain when it would be an advantage to a human for BPG to bind to haemoglobin.