when there is a substitution in the last base, also known as synonymous substitutions
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What are missense mutations?
produces a non functional protein. The change in bases causes the triplet codon to code for another amino acid.
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What are nonsense mutations?
leads to truncated protein as the base change codes for a stop codon.
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What are frame shift mutations?
larger mutations affecting the Open Reading Frame
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What are the types of mutation?
Spontaneous, DNA replication errors, environmentally induced
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What are transition point mutations?
when a purine base is replaced with another purine base, or a pyrimidine base is replaced with a different pyrimidine base.
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What are transversion point mutations?
when a purine base is replaced with a pyrimidine base or a pyrimidine base is replaced with a purine base.
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Discuss mismatch repair
Mismatched bases are recognised by mismatch repair proteins (MSH2 & MSH6). repair proteins recruit an endonuclease. Helicase unwinds the DNA at this site exposing offending mutation where an exonuclease degrades the DNA in the nicked strand
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What is base excision repair?
glycosidase specific for the mutated base flips the base out of the helix and cuts it away from the sugar
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Other cards in this set
Card 2
Front
What are missense mutations?
Back
produces a non functional protein. The change in bases causes the triplet codon to code for another amino acid.
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