Building Blocks Of Life 3

Question 0

What occurs in initiation?

Answer 0

Transcription factors allow RNA pol to bind to promoter on the gene.

Question 1

What are the three steps of RNA synthesis?

Answer 1

Initiation, elongation, termination.

Question 2

How are promotors recognised in eukaryotes?

Answer 2

Due to consensus sequences. TATA box is made consensus sequence.

Question 3

What is the consensus sequence in bacteria?

Answer 3

Hexamere at -35 and Tataat sequence at -10. Promoters are asymmetrical allowing RNA pol to know the direction.

Question 4

What happens in elongation?

Answer 4

By RNA pol, RNA copy is synthesised complimentary to template strand.

Question 5

How does RNA pol work?

Answer 5

RNA pol moves stepwise along DNA stepwise unwinding the DNA helix at the active site. As it progresses RNA pol adds nucleotides at the polymerisation site using exposed DNA strand as template. Rudder on pol allows DNA behind to rewind via the displacement of newly formed RNA.