Transcription Flashcards
(34 cards)
Gene Expression
the production of a functional gene product.
Transcription
the synthesis of a single-stranded RNA molecule
based on base-pairing with a single-stranded DNA template.
Translation
the production of a polypeptide based on an RNA
nucleotide sequence.
Types of RNA
mRNA, tRNA, rRNA.
Not important: miRNA (micro), sn(small nuclear), hn (heterogeneous nuclear)
What facilitates the binding of RNA polymerase in Prokaryotes?
sigma factor
Which of the following statements best describes the
promoter of a protein-coding gene?
a. The promoter is a nontranscribed region of a gene.
b. The promoter is part of the RNA molecule.
c. The promoter is a site at which only RNA
polymerase will bind.
d. The promoter is a site found on RNA polymerase.
a. The promoter is a nontranscribed region of a gene.
What facilitates binding of promoter in Eukaryotes?
transcription factors
Eukaryotic RNA Polymerases
I Nucleolus
II Nucleoplasm
III Nucleoplasm
Where does Eukaryotic transcription occur?
The nucleus
Which three statements correctly describe the processing that takes
place before a mature mRNA exits the nucleus?
a. A translation stop codon is added to the 3’ end of the pre-
mRNA.
b. Sequences called introns are removed by spliceosomes.
c. A polyA tail is added to the 3’ end of the mRNA.
d. Sequences called exons are removed by spliceosomes.
e. A cap consisting of a modified guanine nucleotide is added to
the 5’ end of the mRNA.
f. A ribosome binds the 5’ end of the mRNA.
? Kelly didn’t post the answer
Where does prokaryotic transcription occur?
The cytoplasm
How is Eukaryotic mRNA modified?
- 5’ capping
- 3’ polyadenylation
- Splicing
Processed mRNA is transported to the cytoplasm and translated.
What causes Prokaryotic RNA transcription to stop?
Hairpin Loop
NTPs vs dNTPs
NTP: ribonucleoside triphosphates used by RNA pol in transcription. Have a -OH group on the 2’
dNTPs: deoxyribonuceloside triphosphates used for DNA synthesis
How many RNA pol do bacteria have?
One
How many RNA pol do Eukaryotes have?
Three
Promoters
regions of DNA that promote the start, sites where transcription should begin.
Haloenzyme
bacterial RNA pol core enzyme and sigma together.
Downstream
DNA located in the direction RNA pol moves
Upstream
DNA located in the opposite direction RNA pol moves.
Bacterial Transcription steps
- Initiation begins, sigma binds to promoter.
- RNA pol opens up DNA helix, transcription begins.
- sigma is released, transcription continues
Elongation
enzyme reads DNA template as it catalyzes the addition of nucleotides to 3’ end.
Bacterial Transcription Termination
-RNA pol transcribes a DNA sequence, the transcription-transcription signal. This signal causes RNA to fold back on itself, to form a hairpin.
Transcription differences prokaryotes vs eukaryotes
- Eukaryotes have thee major RNA pol.
- Promoters in eukaryotes are larger and more diverse
- Instead of sigma, eukaryotes use general transcription factors.
- A polyAsignal ends eukaryote transcription
- In eukaryotes, transcription and translation are separated.
