Week 4 Flashcards
What are the 3 steps for Transcription?
- Initiation
- Elongation
- Termination
The top strand starting on 5’ end serves as the ______ strand while the bottom strand starting on the 3’ end serves as the template for the transcriptional process.
Coding
True or false:
The coding strand is the sense strand
True
True or false:
The non-template strand is the sense and coding strand.
True
True or false:
The template strand is the sense strand.
False - the template strand is the strand running 3’ to 5’ and is the antisense strand
True or False:
mRNA is an exact copy of the antisense strand or template strand.
False
mRNA is an exact copy of the coding strand or sense strand
For the process of Transcription, the template strand is the :
Antisense strand (runs in 3’ to 5’ direction) and the mRNA produced will run in 5’ to 3’ direction)
Which strand is the mRNA being produced off of, or is read to make the initial mRNA ?
the template strand that is read in 3’ to 5’ direction
- mRNA synthesized in 5’ to 3’ direction
- the mRNA will match the sense strand/coding strand above the one it is reading
Transcription is similar to DNA synthesis, except for which 4 things ?
- Deoxy nucleotides contain ribose as the sugar
- No primer is needed to initiate process
- Uracil is added instead of Thymine
- RNA polymerase is used instead of DNA polymerase
Genes are specific regions on a chromosome that are comprised of a : _______ region and a ______ (or promoter region)
Transcribed
Regulatory
The transcribed region is _____ of the transcriptional start.
Downstream
The transcribed region contains what 4 things:
- 5’ cap site- required for maturation of mRNA
- Translation start (AUG)
- Introns and Exons
- The poly adenylation site
The promoter region is ____ of the transcriptional start and contains regulatory elements.
Upstream
What elements does the promoter region upstream of the start in transcription contain?
- TATA box (in eukaryotes - Pribnow box in Prokaryotes)
- CAAT or GC box
- Enhancers or repressors (for eukaryotic transcription)
In eukaryotes one gene =
one protein
In prokaryotes one gene =
one mRNA that may code for many genes in tandem- polycistronic (several proteins)
What are the 4 types of RNA?
- mRNA
- tRNA
- rRNA
- snRNA
What is mRNA transcribed by ?
RNA polymerase II
What needs to happen to pre-mRNA before movement in to cytosol for translation ?
5’ capping
Addition of a poly A tail
Splicing (removal of introns)
Where does maturation of mRNA take place?
in Nucleus
True or False:
Prokaryotic mRNA does not require processing
True - transcription is more coupled to translation than in Eukaryotes
What is tRNA transcribed by ?
RNA polymerase III
Does eukaryotic tRNA require maturation?
Yes
What are the maturation steps needed for tRNA?
- Removal of introns
- Addition of the 3’ amino acid attachment site (Trinucleotide CCA)
- Folds into a clover like structure with 3 loops
- Modification of bases to generate non-conventional bases