DNA Mutations

Question 1

What is Deletion?

Answer 1

One nucleotide is lost when DNA is replicated

• All bases after deletion are shifted along one
• Frame-Shift
• Reading of triplet code is affected

Question 2

What is a Nonsense Mutation?

Answer 2

Base change forms stop codon

• Polypeptide is terminated early
• Will not form normal function

Question 3

What is Mis-Sense Mutation?

Answer 3

Base change codes for different amino acid

• Will affect bonding of tertiary structure
• Often leads to malfunctioning protein

Question 4

What is a Silent Mutation?

Answer 4

Substituted base codes for same amino acid

• Because of Degenerate Code
• No effect on Protein

Question 5

How do Mutations create Non-Functioning Proteins?

Answer 5

• Change in DNA base
• Amino acid sequence changed
• Change in H/ionic bonds
• Tertiary Structure is altered (thus shape of active site is altered)
• No enzyme/substrate complexes can be formed