Unit 2 - Mutations

Question 1

What are mutations?

Answer 1

Changes in the DNA that can result in no protein or an altered protein being synthesised

Question 2

What are single gene mutations?

Answer 2

They involve the alteration of a DNA nucleotide sequence due to substitution,insertion, or deletion.

Question 3

What types of single gene mutations are there?

Answer 3

the SUBSTITUTION of one nucleotide with another
the INSERTION of one or more nucleotides into a DNA sequence
the DELETION of one or more nucleotides from a DNA sequence

Question 4

What do substitutions result in?

Answer 4

Either 1. Missense Mutation , 2. Nonsense Mutations or 3. Splice-site mutations

Question 5

What are missense mutations?

Answer 5

They result in 1 amino acid being changed for another resulting in either a non-functional protein or little effect on the protein

Question 6

What are nonsense mutations?

Answer 6

They result in a premature stop coon being produced = shortened protein

Question 7

What are splice-site mutations?

Answer 7

They result in some introns being retained and/or some exons not being included in the mature transcript

Question 8

What does insertion/deletion cause?

Answer 8

Frameshift mutations meaning everything is moved so all amino acids after mutation is changed having a change on the protein produced

Question 9

What types of Chromosome structure mutations are there?

Answer 9

• duplication occurs when a section of a chromosome is added from its homologous partner.
• deletion is where a section of a chromosome is removed.
• inversion is where a section of a chromosome is reversed.
• translocation is where a section of a chromosome is added to a chromosone which is not it’s homologous partner