Exam 1 part 3 Flashcards Preview

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Flashcards in Exam 1 part 3 Deck (11)
1

Central Dogma of Molecular Biology

DNA can replicate itself
DNA can be transcribed to (m)RNA
RNA can be translated to a polypeptide

2

coding strand

where the gene is marked. Includes promoters, +1 site, terminator

3

+1 site

where transcription begins

4

promoter

site where sigma site attaches to place RNA polymerase

5

Molecules involved in transcription

mRNA
transcription factors
template strand
RNA polymerase
NTPs

6

Transcription overview

1. DNA is locally denatured
2. RNA polymerase assembles NTP complementary to the template strand
-reads the template 3'-5'
SYNTHESIZES 5'-3'
No primer needed

7

Steps in transcription

1. Initiation
2. Elongation
3. Termination

8

Initiation in E coli

Sigma binds to 2 conensus sequences
-10 box
-35 box
to orient the polymerase at +1 site
2. RNA polymerase can start synthesizing RNA -does not need a primer

9

nascent

new

10

Termination in E. coli

hairpin in RNA causes pol to stop transcribing
RNA-DNA duplex is dissociated by helicase p (Rho)

11

Prok vs Euk transcription

Prok-1 RNA pol
- no RNA processing
-coupled transcription &translation
polycistronic RNA
Euk-2 RNA pol
-introns removed
-nuclear membrane prevents coupling
-nuclear export
-capping and polyadenylation
monocystronic