Eukaryotic Gene Excl Lee Flashcards
(35 cards)
What is the central dogma
It defines how genetic information flows from DNA to protein
What is the structural difference between RNA and DNA
RNA has a ribose sugar where DNA has a deoxyribose
Which dna base is switched in RNA and what is it switched to
Thymine is switched to uracil
What is mRNA and what is its function
messenger RNA, codes for proteins
What is rRNA and what is its function
Ribosomal RNA, forms the basic structure of ribosomes and catalyses protein synthesis
What is tRNA and what is its function
Transfer RNA, central to protein synthesis as adaptors between mRNA and amino acids
What is snRNA and what is its function
Small nuclear RNA, used to process and chemically modify rRNAs
What is transcription
The transfer of DNA to mRNA
What are the 3 stages of transcription
Initiation, elongation, termination
Where does transcription begin
Transcription begins at regions of DNA called promoters
What sequence do eukaryotic promoters typically contain
Eukaryotic promoters contain sequences called TATA boxes (usually located
25-35 bases upstream of the transcription start site
What is the pre- initiation complex
The pre-initiation complex is a
collection of transcription factors
What is the role of the transcription factors in the pre-initiation complex
These factors work to recruit RNA
polymerase II to the promoter
What is RNA polymerase II
RNA polymerase II is the enzyme
involved in building mRNA strands
from RNA monomers
What is the sequence of events that occurs at the pre-initiation complex ( from 1-7)
1) TFIID contains a subunit called
TBP (TATA box binding protein)
2) TFIIA binds the TBP, recruiting
TFIID to the TATA box
3) TFIIB is recruited and interacts
with the TBP subunit of TFIID
4) TFIIB allows TFIIF to recruit
RNA Pol II to the complex
5) TFIIE binds the complex,
creating a binding site for TFIIH
6) TFIIH is a helicase and
unwinds DNA for RNA Pol II
7) TFIIH also has kinase activity
and phosphorylates RNA Pol II to
activate it and start producing
mRNA
What is the function of the TFIID subunit 1(TBP component) transcription factor
Recognition of the TATA box and possibly Inr sequence; forms
a platform for TFIIB binding
What is the function of the TFIID subunit 2 (TAF component) transcription factor
Recognition of the core promoter; regulation of TBP binding
What is the function of the TFIIA transcription factor
Stabilises TBP and TAF binding
What is the function of the TFIIB transcription factor
Intermediate in recruitment of RNA polymerase II; influences
selection of the start point for transcription
What is the function of the TFIIF transcription factor
Recruitment of RNA polymerase II
What is the function of the TFIIEtranscription factor
Intermediate in recruitment of TFIIH; modulates the various
activities of TFIIH
What is the function of the TFIIH transcription factor
Helicase activity responsible for the transition from the closed
to open promoter complex; possibly influences promoter
clearance by phosphorylation of the C-terminal domain of the
largest subunit of RNA polymerase II
What happens in the elongation phase of transcription
During elongation, RNA Pol II moves down the template strand in a 3’-5’
direction
RNA Pol II builds up the mRNA molecule by adding nucleotides
complementary to the template strand
What is termination
The area where transcription terminates
