MUTATIONS

Question 1

mutations

Answer 1

changes in the DNA that can result in no protein or an altered protein being synthesised

Question 2

single gene mutations

Answer 2

involve the alteration of a DNA nucleotide sequence as a result of the substitution, insertion or deletion of nucleotides

Question 3

nucleotide substitutions: missense mutations

Answer 3

• result in one amino acid being changed for another.
• This may result in a non-functional protein or have little effect on the protein.

Question 4

nucleotide substitutions: nonsense mutations

Answer 4

result in a premature stop codon being produced which results in a shorter protein.

Question 5

nucleotide substitutions: splice-site mutations

Answer 5

result in some introns being retained and/or some exons not being included in the mature transcript

Question 6

nucleotide insertions/deletions: frame-shift mutations

Answer 6

• cause all of the codons and all of the amino acids after the mutation to be changed
• has a major effect on the structure of the protein produced

Question 7

chromosome structure mutations: duplication

Answer 7

Duplication is where a section of a chromosome is added from its homologous partner

Question 8

chromosome structure mutations: deletion

Answer 8

Deletion is where a section of a chromosome is removed

Question 9

chromosome structure mutations: inversion

Answer 9

Inversion is where a section of chromosome is reversed

Question 10

chromosome structure mutations: Translocation

Answer 10

Translocation is where a section of a chromosome is added to a chromosome, not its homologous partner

Question 11

importance of mutation and gene duplication in evolution

Answer 11

duplication allows potential beneficial mutations to occur in a duplicated gene whilst the original gene can still be expressed to produce its protein