MCBG S9 Introduction To DNA Mutations

Question 1

What is a mutation?

Answer 1

A heritable alteration in a gene or chromosome

- Change in nucleotide sequence

Question 2

What are transposable elements?

Answer 2

DNA sequnces that transpose as a unit to random sites.

Question 3

Where are the 3 places a TE could insert itself and what are the resulting effects?

Answer 3

TE into exon of a gene - inactivating it.

TE jump into regulatory sequence - cause uncontrollable activation - wont switch off

TE jumps to non-coding region.

Question 4

What are some exogenous causes of mutation?

Answer 4

Ionising radiation and particles

Mutagenic chemical

Anti-cancel agents

Question 5

What are some endogenous causes of mutation?

Answer 5

DNA replication defects

TEs

Question 6

What is a missense mutation?

Answer 6

Codon for AA changed to another by substitution of base.

Question 7

What is a silent mutation?

Answer 7

Change in base but still same codon coded for.

Question 8

What do frameshift mutations occur as a result of?

Answer 8

Insertions or deletions.

Question 9

What is a non-stop mutation?

Answer 9

Stop codon - no longer stop codon

Question 10

What is a nonsense mutation?

Answer 10

Codon changed into a stop codon

Question 11

Mutations that change the amount of gene product?

Answer 11

• Altered promoter region activity
• Altered start codon
• Prevention of mRNA splicing
• Reducation of mRNA stability.