Flashcards in Session 13-Intro To Mutations Deck (12):
What is a mutation?
Heritable alteration in a gene or chromosome (change in sequence of nucleotides) but also the process that produces the alteration
What are the exogenous ways that can lead to mutations? (2)
Ionising radiation/particles and free radicals
Mutagenic chemicals and anti-cancer agents
What are the endogenous ways that can lead to a mutation? (2)
DNA replication defects
What are transposable elements?
They don't have a fixed position in the genome; they can move to random sites from one chromosome to another
True or false: small genes are easily disrupted by transposable elements
FALSE - large genes are more easily disrupted eg. BRCA1 gene for breast cancer
What are transition changes?
Change to the same type of base:
Purine to purine
Pyrimidine to pyrimidine
What are transversion changes?
Changes to different type of base:
Purine to pyrimidine or vice versa
Where is the mutation for sickle cell anaemia and what type of mutation is it?
Codon 7 of HBB
Base substitution mutation (missense)
One AA change (6th AA) Glu -> Val
Changing one AA to another AA, mutations that change gene products
Which type of mutations do not have an effect? (2)
Silent or neutral mutations
Synonymous mutations (both codons code for same AA)
What type of mutations change the polypeptide length? (3)
1. Frameshift - insertions or deletions
2. Mutations of a stop codon
3. Nonsense mutations - stop codon is created