Mutations

Question 1

What are mutations and the result of them

Answer 1

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

Question 2

3 types of point mutations (substitutions)

Answer 2

Missense, nonsense, splice-site mutations

Question 3

Single gene mutations summary (1)

Answer 3

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

Question 4

Missense mutations

Answer 4

Result in one amino acid being changed for another. This may result in a non - functional protein due to the change of shape of the protein, or have little effect on the protein

Question 5

Nonsense mutations

Answer 5

Result in a premature stop codon being produced which results in a shorter protein which is generally non-functional or its function is affected.

Question 6

Splice- site mutations

Answer 6

Result in some introns being retained and/or some exons not being included in the mature transcript. Results in a very different protein being made.

Question 7

What results in frame- shift mutations

Answer 7

Nucleotides insertions or deletions.

Question 8

What is a frame- shift mutation

Answer 8

When the codon reading frame in the ribosome is shifted by one codon, causing all of the codons and amino acids after the mutation to be changed.
Has a major effect on the structure of the protein produced

Question 9

What results in point mutations

Answer 9

Substitutions of nucleotides

Question 10

Chromosome structure mutations and the 4 types (6)

Answer 10

-alterations that affect whole chromosomes and whole genes.
-The substantial changes in chromosome mutations often are lethal

1- deletion
2- translocation
3. Inversion
4. Duplication

Question 11

Duplication chromosome structure mutations

Answer 11

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

Question 12

Deletion- chromosome structure mutation

Answer 12

Where a section of a chromosome is removed

Question 13

Inversion

Answer 13

Where a section of chromosome is reversed

Question 14

Translocation

Answer 14

Where a section of a chromosome is added to another chromosome which is not its homologous partner

Question 15

Importance of mutations and gene duplication in evolution

Answer 15

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