Unit 1.6: Mutations

Question 1

What is a mutation?

Answer 1

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

Question 2

What are the 3 types of mutations?

Answer 2

• Substitution - bases are switched and only one amino acid is altered
• Deletion - base is deleted from nucleotide sequence, every amino acid after point of deletion will be put out of sequence
• `Insertion- base added to nucleotide sequence, every amino acid after insertion will be altered

Question 3

What are the forms of mutation?

Answer 3

• Point mutation - only a single point in the amino acid is changed
• Frame shift mutation - All the codons and all of the amino acids after the mutation have been changed. This has a major effect on the structure of the protein produced

Question 4

What are the types of substitution?

Answer 4

• Missense - only one amino acid has been changed for another. This may result in a non-functional protein or have little effect on the protein
• Nonsense - results in a premature stop codon being produced which results in a shorter protein
• Splice-site - results in some introns being retained and/or some exons not being included in the mature transcript

Question 5

What are the 4 chromosomal mutations?

Answer 5

• Duplication - where a section of a chromosome is added from its homologous partner
• Deletion - where a section of a chromosome is removed
• Translocation - where a section of a chromosome is added to chromosome not from its homologous partner
• Inversion - where a section of a chromosome is reversed

Question 6

What is the use of mutations?

Answer 6

Mutations provide new genetic material for variation. This is done by mutations producing new alleles. Without mutations there would be no new variation