Transcription Flashcards
Describe the primary and secondary structure of RNA
primary structure is generally single stranded, but RNA can also form some 3-D secondary structures if it is complementary with itself
What is rRNA?
RNA molecule that is a structural component of the ribosome, which is involved in protein synthesis
What is pre-mRNA?
immediate products of transcription in eukaryotes that is processed to mRNA; not in bacteria
What is mRNA?
messenger RNA; RNA molecule that carries the coding instructions for a polypeptide chain from DNA to a ribosome
What is tRNA?
transfer RNA; RNA molecule that carries an amino acid to the ribosome and transfers it to the growing polypeptide chain
What three things does transcription require?
- A DNA template
- raw materials (ribonucleotide triphosphates)
- a transcription apparatus (associated proteins and enzymes)
What is the template strand?
The DNA nucleotide strand that is used as the template during transcription; the RNA synthesized during transcription is complementary and antiparallel to the template strand
What is the coding strand?
The DNA strand that is complementary to the template strand; the RNA transcript will match this strand, except T will be replaced with U
aka the nontemplate strand
What is a transcriptional unit and what are its parts?
A sequence of nucleotides in DNA that encodes a single RNA molecule and the sequences necessary for its transcription
Normally contains a promoter, an RNA-coding region, and a terminator
What is the promoter?
A DNA sequence that the transcription apparatus recognizes and binds to; indicates the direction of transcription, which DNA strand will be the template, and the starting point of transcription
often upstream of the transcription start site
What is a consensus sequence?
A group of common nucleotides (often A and T) in a stretch within the promoter
What is the RNA coding region?
The sequence of DNA nucleotides that is copied into an RNA molecule
What is the terminator?
sequence of DNA nucleotides that brings about the end of transcription
How do rNTPs differ from dNTPs?
rNTPs have a hydroxyl at the 2’ carbon of their sugar (ribose), making it less stable than DNA
RNA nucleotides also utilize U (uracil) instead of T
What is RNA Polymerase and in what direction does it transcribe?
The enzyme that synthesized RNA from a DNA template
works from 5’ to 3’