Mary Jones, Richard Fosbery, Dennis Taylor and, Jennifer Gregory Solutions for Chapter: Genetic Technology, Exercise 16: EXAM-STYLE QUESTIONS

Explain how it is possible to predict the primary structure of a protein from a gene sequence.

Explain how this is possible to find a function for a protein from knowledge of its primary structure alone.

There are varieties of M. persicae that are resistant to many insecticides. The insecticide pirimicarb acts by binding to acetylcholinesterase (AChE) at synapses in insects. The gene Ace codes for acetylcholinesterase which consists of over 500 amino acids. Sequencing of the DNA of this gene found that resistant aphids had a change to a single amino acid in AChE as shown in the diagram.

Explain how a change to a single amino acid in AChE can give resistance to an insecticide such as pirimicarb.

There are varieties of M. persicae that are resistant to many insecticides. The insecticide pirimicarb acts by binding to acetylcholinesterase (AChE) at synapses in insects. The gene Ace codes for acetylcholinesterase which consists of over 500 amino acids. Sequencing of the DNA of this gene found that resistant aphids had a change to a single amino acid in AChE as shown in the diagram.

Other aphid species that showed resistance to pirimicarb had the same change in the primary structure of acetylcholinesterase. Explain how resistance to pirimicarb may have arisen and evolved in a population of M. persicae.

Mutations to BRCA-1 are inherited as autosomal dominant disorders. Explain how the inheritance of this disorder differs from the inheritance pattern for an autosomal recessive disorder, such as cystic fibrosis.

Some mutations in BRCA-1 are much more common in certain groups of people. A deletion of two nucleotides from the gene results in molecules of BRCA-1 that are only 38 amino acids in length. This mutation is more common in Ashkenazi Jews than in other ethnic groups.

Explain why the protein BRCA-1 is only 38 amino acids in length in people with this mutation.

Some mutations in BRCA-1 are much more common in certain groups of people. A deletion of two nucleotides from the gene results in molecules of BRCA-1 that are only 38 amino acids in length. This mutation is more common in Ashkenazi Jews than in other ethnic groups. Explain why particular mutations of BRCA-1 are more likely to occur in certain ethnic groups.

Some countries have genetic screening programmes for breast cancer. Suggest the implications of the higher frequency of some mutations in certain ethnic groups for these screening programmes.