1.6 Mutations

Question 1

Define a ‘Mutation’

Answer 1

a change in the DNA that can result in no protein or an altered protein being synthesised.

Question 2

What are the two types of mutation?

Answer 2

1. Single gene mutation
2. Chromosome structure mutation

Question 3

Describe what a single gene mutation is

Answer 3

the alteration of a DNA nucleotide sequence of a single gene.

Question 4

State the three types of single gene mutation

Answer 4

1. Substitution
2. Insertion
3. Deletion

Question 5

What is the effect of a substitution mutation on DNA?

Answer 5

One (or more) bases are replaced by another

Question 6

What is the effect of a substitution mutation on the protein?

Answer 6

One amino acid is changed for another

Question 7

What are the three types of substitution mutation?

Answer 7

1. Missense
2. Nonsense
3. Splice-site Mutation

Question 8

Describe the effect of a missense mutation on the DNA and protein

Answer 8

DNA = One (or more) bases are replaced by another.
Protein = One amino acid is changed for another, this may result in a non-functional protein or have little effect on the protein.

Question 9

Describe the effect of a nonsense mutation on the DNA and protein

Answer 9

DNA = results in a premature stop codon.
Protein = produces a shorter protein

Question 10

Describe the effect of a splice-site mutation on the DNA and protein

Answer 10

DNA = Substitution results in some introns being retained or some exons being removed from the mature transcript.
Protein = Result in a longer or shorter protein.

Question 11

What are a missense, nonsense, splice-site mutations all an example of?

Answer 11

Types of substitution mutation

Question 12

Insertion and deletion mutations are both examples of a?

Answer 12

Frameshift mutation

Question 13

Describe the effect of a insertion mutation on the DNA and protein

Answer 13

DNA = One (or more) bases are added to the DNA causing a frameshift which changes all the codons after the mutation
Protein = Changes all the amino acids after the mutation resulting in a major effect on protein structure.

Question 14

Describe the effect of a deletion mutation on the DNA and protein

Answer 14

DNA = One (or more) bases are removed from the DNA causing a frameshift which changes all the codons after the mutation
Protein = Changes all the amino acids after the mutation resulting in a major effect on protein structure.

Question 15

State the four types of chromosome structure mutation

Answer 15

1. Deletion
2. Translocation
3. Duplication
4. Inversion

Question 16

Describe what a homologous chromosome is

Answer 16

There are two copies of each chromosome (one maternal and one paternal) which share the same genes and are the same size.

Question 17

Describe a chromosome structure deletion mutation

Answer 17

When a section of a chromosome is removed

Question 18

Describe a chromosome structure translocation mutation

Answer 18

When a section of a chromosome is added to a chromosome, not its homologous partner.

Question 19

Describe a chromosome structure duplication mutation

Answer 19

When a section of a chromosome is added from its homologous partner

Question 20

Describe the advantage of a duplication mutation

Answer 20

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

Question 21

Describe a chromosome structure inversion mutation

Answer 21

When a section of a chromosome is reversed