B5.1.7 - Mutations

Question 1

What is a mutation?

Answer 1

Change in the sequence of DNA bases

Question 2

What substances can increase the chance of a mutation occurring?

Answer 2

Benzene, ethanol and ionising radiation such as ultraviolet

Question 3

What is a genetic variant?

Answer 3

A different version of an allele caused by a change in the DNA.

Question 4

What are the harmful effects of mutations?

Answer 4

• They can cause cancer, when the cells grown and divide uncontrollably
• They cause the production of abnormal protein channels that do not function properly such as in cystic fibrosis
• Abnormal proteins channels allows molecules to be transported through the cell membrane
• They cause different shaped protein molecules to be made

Question 5

What happens if a mutation occurs within a gene?

Answer 5

DNA bases may be changed, added or deleted. This changes the sequences of bases, so the order of base (in mRNA) produced during transcription may be different.
This can lead to amino acids assembled in a different order leading to the wrong protein being produced or it may fold incorrectly and form a different shape