Unit 1.4 Gene mutations

Question 1

What is a missense mutation?

Answer 1

A substitution mutation where one amino acid codon is replaced with another, meaning one amino acid will be changed from another in the protein chain

Question 2

What is a mutagenic agent?

Answer 2

A substance which artificially increases mutation rate

Question 3

What is a mutation?

Answer 3

A change in the DNA structure or composition which causes a change in the phenotype

Question 4

What is an example of a missense mutation?

Answer 4

sickle cell disease

Question 5

What is a nonsense mutation?

Answer 5

Also a substitution mutation where one nucelotide is replaced with a premature stop codon which results in a shorter protein

Question 6

What is an example of a nonsense mutation?

Answer 6

Duchenne muscular dystrophy

Question 7

What is a splice site mutation?

Answer 7

This mutation may alter the codons that trigger the removal of introns in translation, resulting in some introns being retained and/or some exons being excluded from the mature mRNA transcrip

Question 8

What is an example of a splice site mutation?

Answer 8

Beta-Thalassemia

Question 9

What is a deletion mutation? (FRAMESHIFT)

Answer 9

A nucleotide is removed from the sequence. This causes all the codons and therefore all the amino acids after the mutation to be changed

Question 10

What is an example of a deletion mutation? (FRAMESHIFT)

Answer 10

Cystic Fibrosis

Question 11

What is an insertion mutation? (FRAMESHIFT)

Answer 11

An extra nucleotide is added to the sequence. This causes all of the nucleotides and therefore all the amino acids after this mutation to be changed

Question 12

What is an example of an insertion mutation? (FRAMESHIFT)

Answer 12

Tay-Sachs Syndrome