Chapter 18 Flashcards
(17 cards)
Define mutation
Alteration in DNA sequence
- Differentiate between somatic mutation and germline mutation
Somatic is in somatic tissues, which affect organism but not gametes (Unlike germline mutation)
- Define base substitution
One nucleotide is changed for another
- Differentiate between transitions and transversions
Transition- Purine->purine or pyrimidine -> pyrimidine
Transversion- Purine -> pyrimidine or vice versa
- Define insertions and deletions and state what type of mutation these cause
Nucleotide added/removed- frameshift
- Define in-frame insertions and deletions and describe how they arise
Insertions/deletions (indels) that don’t affect reading frame- insertions/deletion of a whole codon
- Define expanding nucleotide repeats
Mutation causing increasing number of copies in a set of nucleotides
- Explain how strand slippage can cause expansion of nucleotide repeats
Bubble forms in new strand, when it’s straightened out extra nucleotides are filled in
- Define and describe 3 effects base substitutions can have on the amino acid sequence
Missense changes AA, Nonsense ends it prematurely, Silent doesn’t change AA sequence
- Differentiate between forward mutation and reverse mutation
Forward changes WT to mutant, reverse changes mutant back to WT
neutral mutation,
Alter DNA sequence, not helpful or harmful
- Define suppressor mutation
Alleviates effects of an existing mutation
- Define intragenic suppressor mutations
Mutation in a gene that restores original function of the same gene gene
Describe mismatch repair as below:
o mismatched bases distort DNA structure
o distorted section cut out and replaced
loss-of-function mutation,
Inactivates a gene
gain-of-function mutation,
altered genes or noncoding RNAs possess a new molecular function or a new pattern of expression
lethal
mutation
Fatal or greatly reduces lifespan
