Mutation

Question 1

What is a mutation?

Answer 1

A random change to the genome of an organism.

Question 2

Name the three types of gene mutations?

SID

Answer 2

Substitution, Insertion, Deletion

Question 3

Name the four types of chromosomes mutations?

Answer 3

Translocation, Inversion, Deletion, Duplication

Question 4

What happens in a substitution mutation?

Answer 4

One base is replaced by another

Question 5

What happens during deletion point mutations?

Answer 5

One base is removed

Question 6

What happens during insertion point mutations?

Answer 6

One base is added

Question 7

What is meant by a missense mutation?

Answer 7

When one amino acid has been substituted for another.

Question 8

What is meant by a nonsense mutation?

Answer 8

When a premature stop codon has been inserted.

Question 9

What is the result of a splice-site mutation?

Answer 9

An intron could remain in the mature mRNA or an exon may have been removed.

Question 10

Which mutations lead to a frameshift effect?

Answer 10

Insertion and deletion

Question 11

What is meant by a frameshift effect?

Answer 11

Each codon after the mutation is altered leading to the wrong amino acids being used.

Question 12

What is meant by a chromosome mutation?

Answer 12

A change to the number or sequence of genes on a chromosome.

Question 13

What happens in a translocation mutation?

Answer 13

A section of one chromosome becomes attached to another.

Question 14

What happens in an inversion mutation?

Answer 14

Genes on the chromosome are flipped (or rotate 180°).

Question 15

What happens in a deletion chromosome mutation?

Answer 15

Genes from the chromosome are deleted.

Question 16

What happens in a duplication mutation?

Answer 16

Genes on the chromosome are repeated.

Question 17

What is polyploidy?

Answer 17

An organism which has an extra set of chromosomes.

Question 18

How does polyploidy occur?

Answer 18

Failure of spindle fibres to separate chromosomes during mitosis or meiosis.

Question 19

How does polyploidy help drive evolution?

Answer 19

It provides material upon which natural selection can act.

Question 20

Give two features of polyploidy plants which make them beneficial?

Answer 20

Increased yield, increased vigour.

Question 21

Which type of point mutation can lead to an expansion of a nucleotide sequence?

Answer 21

Insertion

Question 22

What is meant by a silent mutation?

Answer 22

When the mutation leads to the same amino acid being produced.

Question 23

What is meant by a neutral mutation?

Answer 23

An amino acid with similar properties is used so the protein still functions correctly.

Question 24

Explain how a mutation can lead to the same amino acid being produced?

Answer 24

Many amino acids have more than one codon.

Question 25

What would the effect of a mutation in a regulatory sequence?

Answer 25

Failure in gene expression

Question 26

Give an example of a mutagenic agent?

Answer 26

Mustard gas, U.V. Radiation, X-Rays

Question 27

What is a mutagenic agent?

Answer 27

Something which increases the frequency of mutations.

Question 28

How often do mutations occur?

Answer 28

Randomly, rarely, spontaneously.