November 6th micro notes

I. Transcription: DNA  RNA
DNA(Instructions! – like a blueprint  RNA Protein (building block of organism) First step is Transcription) (second step is called translation)
Gene ~ DNA instructions for a particular protein.
1. Initiation – determining which bit of DNA will be copied to RNA (DNA must be unwound, unzipped before it can be transcribed) (this is because signle strand serves as a template for RNA copy)
a) RNA polymerase(Enzyme that copies DNA into RNA Copy. (RNA copy is single-stranded, complementary to one DNA strand)(RNA polymerase binds to promoter sequences on DNA): sigma factors(subunit) – subunit of RNA polymerase that binds to DNA promoter sequences. Different factors attach to different promoter sequences. (different sigma factors attach to different promoter sequences)(Different sigma factors expressed under different conditions) (attaches to promoter sequences on DNA) (different igma factors produced in response to different environmental conditions)
b) Promoter sequence on DNA – where transcription initiation occurs: where DNA is unwound and unzipped so RNA copy can be made (have lots of T and A) (TATA box – TATAAT – like sequence at almost all promoter sites)(While have common TATA – box sequence, also have variability in surround bases)(specific sequence of bases on DNA that RNA polymerase(enzyme that make RNA copy of DNA strand) attaches to)(Pg. 261 gives examples of these)(variability in promoter sequences though some consensus)
c) Rifampin Binds Bacterial, But not eukaryotic or archaeal, RNA polymerase

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