Transcription Flashcards
What is the pathways of information transfer in cells?
- DNA synthesis (DNA replication)
- RNA synthesis (transcription)
- protein synthesis (translation)
what two regions does each gene have?
regulatory and coding regions
what are regulatory regions?
nucleotide sequences which can increase or decrease gene expression
what is a promoter?
a sequence of DNA where proteins bind to initiate transcription (part of the regulatory region)
What are the three coding regions called?
- transcription start site
- exons
- termination region
Where are the coding regions usually found?
- the transcription start site in usually next to the promoter sequence
- exons are between the start site and termination region
- the termination region is found at the end
What are introns?
noncoding sections of an RNA transcript that aresplicedout before the RNA molecule is translated into a protein
where does transcription take place?
in the nucleus
what is the process of producing RNA and proteins from a gene called?
gene expression
what is the main RNA class involved in protein synthesis?
- mRNA
What four elements are required for transcription to take place?
-a starting DNA template
-a transcription unit
(promoter, RNA coding sequence, terminator)
- the machinery for transcription
- rNTPs
what are the two stands of DNA called in transcription?
- coding strand
- template strand
from which strand of DNA are genes transcribed?
the template strand
in which direction does translation take place?
5’ to 3’
what is RNA polymerase?
an enzyme that synthesises RNA using a DNA template
what do the promoter, RNA coding region and terminator represent together?
a transcription unit
What are the three sequential stages of transcription?
- initiation
- elongation
- termination
What happens during the initiation stage of transcription?
the transcription machinery recognises and binds to the promoter to start synthesis from DNA (no primer needed)
What happens during the elongation stage of transcription?
the RNA polymerase moves along the template during elongation and synthesises RNA, adding nucleotides at the 3’
What happens during the termination stage of transcription?
the enzyme dissociates at the end of the transcription unit and releases RNA
What must happen to chromatin structure for transcription to occur?
Chromatin structure must be modified by regulatory proteins binding near the promoter to make the DNA accessible
Where is the information about the frequency and level of transcription located?
In the promoter
What enzyme is responsible for transcription, and what additional proteins assist?
RNA polymerase (multisubunit, multifunctional) is the enzyme, assisted by accessory proteins, transcription factors, and the mediator complex.
Why does eukaryotic RNA polymerase need many accessory proteins?
becuase it can’t recognise the DNA sequence on it’s own
