A-level BIOLOGY Paper 3

A-level BIOLOGY Paper 3The mutation that caused the C G allele was due to a 24 base-pair deletion from the outside the box C allele. . 4 The protein coded for by the CB allele is 306 amino acids long. Calculate the percentage reduction in size of the protein coded for by the CB allele compared with the protein coded for by the CG allele. Give your answer to 3 significant figures and show your working. [2 marks] Answer In S. carolinensis, fur colour depends on the distribution and relative amounts of light pigments and dark pigments in the hairs of the fur. Figure 1 shows how the protein produced from the CG allele can result in the production of a light pigment or a dark pigment. Figure 1 0 1 5 Do not write *05 * IB/H/Jun21/7402/3 9 The deletion mutation in the CB allele results in the production of a receptor protein that does not have glutamic acid. The lack of glutamic acid in the receptor protein has the same effect as αMSH leaving the receptor protein. . 5 Use Figure 1 and this information to suggest why S. carolinensis with the genotype CBCB have black fur rather than grey fur. outside the box [3 marks] Turn over for the next question Turn over ► 0 1 6