Lecture 8

Question 1

What are the different types of DNA mutations?

Answer 1

1. Point mutations
2. Insertions and deletions
3. Gene deletions
4. Translocations
5. Complex chromosomal arrangements

Question 2

Which are the purines and pyrimidines?

Answer 2

Pure As Gold
Purines - Adenine and Guanine
Pyrimidines - Cytosine, Thymine and Uracil

Question 3

What does the effect of the mutation depend on?

Answer 3

Where it occurs, whether it be the cider sequence or in the promoter or non-coding regions.

Question 4

What is a frameshift mutation?

Answer 4

An insertion where the number of nucleotides is not a multiple of 3 which could lead to a premature stop codon.

Question 5

What happens when you move to the gene and chromosomal level?

Answer 5

Duplications of sections and inversions.

Question 6

What is a trinucleotide repeat expansion? and what are some examples?

Answer 6

A series of 3 bases gets repeated over and over again.
Huntington’s disease
Fragile X syndrome - Repeats in the non-coding part of genes causes a reduction in expression and therefore loss of gene function
Myotonic Dystrophy - muscle weakness

Question 7

What is cystic fibrosis

Answer 7

A build up of mucous in the lungs

Question 8

What type of inheritance is cystic fibrosis?

Answer 8

Autosomal recessive

Question 9

What causes sickle cell anaemia? + type of inheritance?

Answer 9

Single nucleotide missense mutation. Autosomal recessive

Question 10

Haemophilia inheritance ans cause

Answer 10

X-linked recessive. 2 types:
A - Mutations in Factor 8 gene
B- Mutations in factor 9 gene
Causes - Deletions, point mutations and rearrangements