Page 123 - Genetics_From_Genes_to_Genomes_6th_FULL_Part2

282 Chapter 8 Gene Expression: The Flow of Information from DNA to RNA to Protein

FEATURE FIGURE 8.10

Transcription in Bacterial Cells
(a) The initiation of transcription
1. RNA polymerase factor
core enzyme
3' 3'
5' 5'
Termination
Promoter region
2. RNA-like strand Nascent mRNA

3'
3'
5'
5' 5'
3'
factor released
Template strand
Direction of transcription
(b) Elongation
Transcription bubble
1.
DNA rewinds
3'
3'
3' 5'
5'
Promoter region Termination
5' mRNA region
RNA polymerase movement

2.

Promoter Transcription

(c) Termination
Termination region

3' 3'
5'
5'
Termination signal
A hairpin loop termination signal
3'
mRNA
5'
RNA polymerase released
at terminator
5' UAAUCCCACAG C C GC CAGUUCCGCUG 3'
GC G G CAUUUU

b.2: © Professor Oscar Miller/SPL/Science Source
(Continued)