1.6 Mutations

Question 1

Define a ‘Mutation’

Answer 1

A random irreversible change to an organism’s DNA sequence resulting in no protein or an altered protein be produced

Question 2

What are the two possible results of a mutation?

Answer 2

• No protein produced

- Altered Protein

Question 3

How can a mutation affect the phenotype?

Answer 3

Mutation will result in a change to amino acid sequence meaning altered protein / no protein produced. The proteins produced determines the phenotype. This means the phenotype is altered.

Question 4

What are the three types of single gene mutations?

Answer 4

• Substitution
• Insertion
• Deletion

Question 5

What are three types of substitution mutations?

Answer 5

• Missense
• Nonsense
• Splice Site

Question 6

What is a missense substitution mutation?

Answer 6

Missense - causes the change to one amino acid

Question 7

What is a splice site substitution mutation?

Answer 7

A mutation which changes the boundaries between exons and introns, resulting in introns staying in mature transcript

Question 8

What is a nonsense substitution?

Answer 8

A mutation when one triplet is changed to form a stop codon

Question 9

A nonsense mutation results in a … being produced which results in a shorter protein.

Answer 9

premature stop codon.

A nonsense mutation results in a premature stop codon being produced which results in a shorter protein.

Question 10

What is the result of a missense mutation?

Answer 10

May result in a non-functional protein or have little a effect on the protein

Question 11

What kind of substitution can result in a change to the mature mRNA transcript?

Answer 11

Splice site - results in introns being left in and alters final protein produced

Question 12

What is a frame shift mutations?

Answer 12

Mutation resulting in all of the codons and all of the amino acids after the mutation to be changed

Question 13

What type of single gene mutations result in a frame shift mutations?

Answer 13

Insertion

Deletion

Question 14

What are the four types of chromosome mutations?

Answer 14

Duplication
Deletion
Inversion
Translocation

Question 15

Describe an inversion chromosome mutation

Answer 15

An inversion mutation is where a segment of the chromosome breaks off, is inverted 180 degrees and attaches back onto the same chromosome

Question 16

Describe a duplication chromosome mutation

Answer 16

A section of the chromosome is duplicated from the homologous partner and genes are repeated.

Question 17

What type of chromosome mutation decreases the length of the chromosome?

Answer 17

Deletion

Question 18

What is a translocation chromosome mutation?

Answer 18

Segment of chromosome breaks off and attaches to its non homologous chromosome partner

Question 19

Which type of chromosome mutation is most important in terms of evolutionary terms and why?

Answer 19

Duplication

• provides extra genetic material
• can undergo mutation
• increases chance of a new gene being created

Question 20

What is the main difference between a gene mutation and a chromosome mutation?

Answer 20

Gene mutation - change to a single triplet of bases in a gene
Chromosome mutation - change to the gene sequence in a chromosome (structure of chromosome)