This question relates to the following quote of James Watson who, along with Francis Crick, published the three-dimensional structure of DNA in 1953:

‘Bad genes are actually mutated good genes that, because of altered DNA messages, do not function normally’.

With reference to cystic fibrosis, explain the nature of mutations found in the cystic fibrosis gene, the difference between the function of the product of the ‘good gene’ and the function of the product of the ‘bad gene’, and how the difference in function can be related to the cystic fibrosis phenotype. You should include at least one diagram.

You can assume that the reader understands how proteins are made from DNA by transcription and translation and the meaning of all the scientific terms, so you don’t have to explain them. You should be able to answer in about 300 words.