Gene expression Flashcards
(42 cards)
What are two purines
Guanine
Adenine
What are the two pyrimidines
Thymine
Cytosine
What type of helical structure does RNA have
right handed
Is RNA more reactive or DNA and why
RNA- has 2’OH
What are all cellular RNA’s transcribed from
DNA templates
What is the production of RNA from DNA carried out by
DNA-dependent RNA polymerases
Whats the tole of RNA polymerase
Couples together ribonucleotide triphosphatases (NTPs: ATP, CTP, GTP, UTP)
Where does RNA polymerase work and what is it driven by
On DNA template
-driven by release and hydrolysis of PPi
What contains RNAP
All cells
Why is RNA synthesis easier in prokaryotes
RNA synthesis is initiated at DNA specific sites;
- expression involves small, single stand genome portions
- no primer needed and template fully conserved
what does the DNA serve as in prokaryotic transcription
Antisense/noncoding strand
What is the same sequence as sense/coding strand
RNA (except for T)
What are structural genes
Protein-coding genes
How are structural genes transcribed in eukaryotes
Transcribed individually
How are structural genes transcribed in prokaryotes
Transcribed together
where is transcription initiated
At a promoter
Where does RNAP bind
Initiation site through base sequence known as promoters
Where do promoters lie
Lies upstream of RNA’s starting molecule
In which direction does RNA synthesis proceed
5-3
What does the binding of the RNAP holoenzyme lead to
DNA ‘melting’ (separation) in its vicinity (transcription bubble)
What does the formation of. a transcription bubble allow
Allows complementary RNA strand synthesis
the bubble travels with RNAp
What does a processive RNA polymerase mean
Does not dissociate from template
When can protein synthesis begin before RNA is completely synthesized
In prokaryotes
How is transcription terminated in prokaryotes
DNA contains specific termination sites
