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

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

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

Answer 9

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

Question 10

What is a frame shift mutations?

Answer 10

Mutation resulting in an unnatural reading position of the amino acids

Question 11

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

Answer 11

Insertion

Deletion

Question 12

What are the four types of chromosome mutations?

Answer 12

Duplication
Deletion
Inversion
Translocation

Question 13

Describe an inversion chromosome mutation

Answer 13

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

Question 14

Describe a duplication chromosome mutation

Answer 14

A section of the chromosome is duplicated, and genes are repeated

Question 15

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

Answer 15

Deletion

Question 16

What is a translocation chromosome mutation?

Answer 16

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

Question 17

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

Answer 17

Duplication

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

Question 18

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

Answer 18

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)

Question 19

What is a Polyploid?

Answer 19

When the organism contains extra sets of chromosomes within the genome

Question 20

How many sets of chromosomes does a tetraploid have?

Answer 20

4n

Question 21

How many sets of chromosomes does a triploid contain?

Answer 21

3n

Question 22

What is Polyploidy?

Answer 22

The failure of spindle fibres to separate during cell division resulting in extra sets of genetic material

Question 23

Why are polyploid organisms important in evolutionary terms?

Answer 23

Provide extra sets of chromosomes which increase the chance of mutations
Mutations may lead to advantageous change in genotype

Question 24

Describe why polyploid crops important for human food production

Answer 24

Produce more turgid crops/ larger fruits or seeds which grow fasts
Help food security

Question 25

Give an example of a polyploid food

Answer 25

Banana - triploid

Potato - tetraploid

Question 26

What is a regulatory sequence mutation and what can it effect?

Answer 26

Regulatory Sequence Mutation - mutation that occurs at non coding regions
Effect: Gene expression