Lecture 16- RNA Transcription Flashcards
What are the two strands of DNA when talking about RNA transcription?
The template strand (off of which the RNA is made), and the coding strand (has the same base pairs as the RNA).
What are the three steps for transcription?
Initiation, elongation, termination.
What happens during initiation?
The holoenzyme binds to the promoter, which sits at -35 and -10. The holoenzyme will then unwind around 10 base pairs of DNA.
What are the core enzyme and the holoenzyme?
The holoenzyme initiates transcription using its sigma factor. Then, the core enzyme continues transcription, elongating the RNA. Both are RNA polymerases!
What happens during elongation?
The hydrolysis of ATP provides the energy for the polymerase (holoenzyme) to start moving. At this point, the sigma factor is no longer needed (enzyme could become core enzyme). During elongation, the 9 newest bases interact with the template strand of DNA to stabilize.
What happens during termination?
A terminator sequence in the DNA stops the movement of the polymerase. This can form a hairpin structure in the new RNA, which causes the polymerase to stop and dissociate.
What did Beadle and Tatum conclude and what did their experiments look like?
They concluded that the genes within DNA are responsible for the synthesis of proteins.
Their experiments used mutated genes and tested to find that if given the protein that the mutated could no longer synthesize, then the reaction pathway could still occur. This proved that mutating genes caused proteins to malfunction or not appear.
