Week 5 Flashcards
Gene regulation, transcription, and translation
What is the central dogma of molecular biology
- DNA is transcribed into RNA
- RNA is translated into protein
What is transcription?
The synthesis of an RNA molecule from a DNA template
What are the three major components of transcription?
- A DNA template
- The raw materials to build the RNA molecule
- The transcription apparatus
What is the template strand
The DNA nucleotide strand being used for transcription
What is the transcription unit?
The stretch of DNA on the template stand that encodes an RNA molecule and the sequences needed for its transcription
What three things are included in the transcription unit?
- A promoter
- An RNA coding sequence
- A terminator
What is the promoter in a transcription unit?
DNA sequence that the transcription apparatus recognizes and binds to
What three things are determined by the promoter in a transcription unit?
- Which of the two DNA strands is to be read as the template
- The direction of transcription
- The transcription start site
T or F: In many transcription units, the promoter region is located next to the transcription start site, but it itself is not transcribed.
True
What is the RNA coding region in a transcription unit?
The sequence of DNA nucleotides that is copied into an RNA molecule
What is the terminator in a transcription unit?
The sequence of DNA nucleotides that signals where transcription is to end
Is the terminator sequence typically included in the RNA coding sequence?
Yes because transcription stops after the terminator has been copied into RNA
T or F: Upstream refers to movement from the 3’ end to the 5’ end.
False. Upstream or downstream is relative to the point of reference.
Is the promoter sequence upstream or downstream of the transcriptional start site?
Upstream
Is the termination sequence upstream or downstream of the transcriptional start site?
Downstream
Is the RNA-coding sequence upstream or downstream of the promoter?
Downstream
Is the RNA-coding sequence upstream or downstream of the termination site?
Upstream
What is the orientation of the template strand?
3’ to 5’
In which direction is the template strand synthesized/transcribed?
5’ to 3’
RNA synthesis is ____________ and ____________ to the template strand.
Complimentary, Antiparallel
How does the sequence of the transcribed RNA sequence differ from the non-template strand?
They have the same sequence (both complementary to the template strand), but U is substituted for T in the RNA strand
What is the difference between genes being transcribed on the top (+) and genes being transcribed on the bottom (-) strand of the DNA?
Whether the transcription takes place from left to right or right to left (always read 3’ to 5’ and transcribed 5’ to 3’, but because the strands are antiparallel, the 3’ and 5’ ends are different each)
When being numbered, which nucleotide is labelled as +1?
The first nucleotide being transcribed
Are nucleotides downstream from the start site assigned positive or negative numbers?
Positive numbers
Are nucleotides upstream from the start site assigned positive or negative numbers?
Negative numbers
What is the transcription apparatus made of?
RNA polymerase
What is the role of RNA polymerase during transcription?
Synthesizes RNA from the DNA template
Where does RNA polymerase bind during transcription?
The promoter region
What is RNA polymerase II responsible for?
Generating the majority of mRNA for making proteins
T or F: Transcription in eukaryotes is a complex and highly regulated process.
True
What is an operator?
The binding site for a repressor protein