Lecture 14 Flashcards
How can mutations be induced?
Through mutagens such as base analogues, base alteration, damage a base
What is the difference between a transition and transversion mutation?
Transitions are where purines and pyrimidines are exchanged for another base of the same type
Transversions are where bases are exchanged for bases of different types
What is the difference between a silent and synonymous mutations?
Both mutations do not result in a change in the amino acid sequence, synonymous mutations are a subclass of these mutations which occurs in exons
What are the types of non-synonymous mutations?
Non-sense mutations is when a premature STOP codon is formed, resulting in severe functional change in a protein
Missense mutations where there is a change in the amino acid sequence, these can be conservative where the amino acid is functionally similar or nonconservative where the amino acid is functionally different
What are the two types of mutations that cause frameshifts?
Base insertions or deletions
How do base analogs cause mutations?
The are incorporated into DNA where they cause mispairing
How do alkylating agents cause mutations?
Modification of bases changing pairing E.g. Ethyl methane sulphonate alkylates G so it pairs with T
How do intercalating agents cause mutations?
Bind between bases in DNA often causing base deletions or insertions and frame shifts
What is the Ames test?
A mechanism of testing reversion to determine the nature of mutations, does not show deletions
What mutations can be reversed by nitrous acid?
Transitions (GC -> AT), (AT -> GC)
What mutations can be reversed by Proflavin?
Frameshift mutations
What mutations can be reversed by hydroxylamine/ Ethyl metahne sulfonate?
Transition (AT -> GC)
