Mutations

Question 1

Mutation

Answer 1

A permanent change in DNA resulting in a variation in alleles of a gene. If a mutation occurs in the egg or sperm, this can lead to variation within a population. Not all mutations are bad e.g. natural selection & evolution.

Question 2

When do Mutations Occur?

Answer 2

During DNA replication. The base sequence is changed and mistakes occur in the manufacturing of the proteins.

Question 3

Types of Gene Mutations

Answer 3

There are 4 main types of gene mutations. Silent, missense, nonsense, and frameshift.

Question 4

Silent Mutations

Answer 4

A single base is changed and doesn’t affect the protein.

Question 5

Missense Mutations

Answer 5

A single base is substituted. Change doesn’t stop the gene from making the protein, but the protein will be different. The protein may not function or cause disease. e.g. sickle cell anemia.

Question 6

Nonsense Mutations

Answer 6

Cause the cell to stop reading the gene before it finishes. This causes a disfunctional protein. e.g. cystic fibrosis.

Question 7

Frameshift Mutations

Answer 7

Caused by the insertion/deletion of one or more bases. All following genetic info becomes jumbled, so it can’t be read to make a protein.

Question 8

Mutagens

Answer 8

Agents that cause mutations. i.e. chemicals, radiation, pathogens. e.g. UV, X - Rays (in high amounts), processed food, carcinogens, viruses, bacteria.