BIOL 142 Lecture Notes - Lecture 2: Tata Box, Sense Strand, Enzyme
Thursday, January 25, 2018
BIOL 142
•Coding sequence is read in 5’-3’ direction"
•Copy is complementary and anti-parallel"
•Mutations"
•Silent - does not change the aa specified by the codon"
•Missense - change in nucleotide sequence that changes the aa specified by the
codon"
•Nonsense - change in nucleotide sequence that results in a early stop codon
(changes it to a stop codon)"
•Frameshift - addition or deletion of nucleotide"
•Mutation categories"
•Beneficial mutations - increase the fitness"
•Neutral mutations - Do not affect fitness (silent)"
•Deleterious mutations - decrease the fitness"
•Most mutations are neutral or slightly deleterious"
•Things we need for transcription"
•Template"
•Initiation"
•Separation of strands"
•Polymerase activity"
•Termination "
•Start and stop codons are not relevant here"
•Sense strand (non-template, coding strand) & anti-sense strand (template strand)"
•Sense strands looks like how the RNA would look (except there are Us instead of Ts)"
•RNA polymerase (sigma a holoenzyme) - holoenzyme meaning the enzyme complex"
•Sigma (interface with the substrate) - initiation/promoter recognition"
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