Mutations Flashcards Preview

BLGY1232 Introduction to genetics > Mutations > Flashcards

Flashcards in Mutations Deck (11):
1

What does 5'-->3' exonuclease activity do?

Chews away ahead of polymerase

2

What does 3'-->5' exonuclease activity do?

Checks for mismatches and removes them. Allows it to reincorporate the correct base pair and increases the fidelity of the DNA polymerase.

3

What does mutation mean?

Change in chromosome number, chromosome structure or DNA sequence

4

What are point mutations and give 3 examples

Single base changes
1. Mis-sense (result in a different amino acid)
2. Non-sense (result in premature termination)
3. frame-shifts (results from insertion/deletion of 1 or 2 bases)

5

What are larger scale mutations and give 2 exmaples?

changes of longer sequences
1. Deletions (loss of part or all of a gene)
2. Insertions (genes disrupted by insertion of large sequences)

6

What are the causes of spontaneous mutations?

Result of errors in replication, chemical changes to bases and insertions resulting from transposon activity

7

What are the causes of induced mutations?

Chemical changes by mutagens, changes caused by radiation and insertions from transposon activity

8

What is replication error usually associated with?

A run of bases, a base is looped out so isnt read by the polymerase

9

What can dinucleotide or trinucleotide repeats result in?

Insertion or deletion of 2 or 3 bases due to looping out.

10

What do mis-sense mutations cause?

A codon to change its codng specificity from one amino acid to another, may result in a change from a basic to acidic amino acid.

11

What do non-sense mutatios cause?

Creates a truncated protein, may have no or partial activity depending on where the mutation occurs.