16 - Transcription Flashcards
Transcription
is the synthesis (production) of RNA using information in the DNA
Translation
is the synthesis of a polypeptide using the information in the mRNA
Triplet
the genetic instructions for a polypeptide chain are written in the DNA as a series of nonoverlapping, three-nucleotide words
Template strand
1/2 DNA strands that is transcribed, it provides the pattern, or template, for the sequence of nucleotides in an RNA transcript
Nontemplate / coding strand
is the DNA strand that has the same sequence as the RNA transcript being produced, except that thymine (T) in DNA is replaced by uracil (U) in RNA.
Promoter
The DNA sequence where RNA polymerase attaches and initiates transcript
Transcription unit
the stretch of DNA downstream from the promoter that is transcribed into a RNA molecule
TATA box
is a short DNA sequence found in the promoter region of many genes in eukaryotes
Transcription factors
A collection of proteins in eukaryotes that help guide the binding of RNA polymerase and the initiation of transcription
RNA polymerase 2
is an enzyme in eukaryotic cells responsible for transcribing DNA into messenger RNA (mRNA).
Initiation
After RNA polymerase binds to the promoter, the polymerase unwinds the DNA strands and initiates RNA synthesis at the start point on the template strand
Elongation
The polymerase moves downstream, unwinding the DNA and elongating the RNA transcript 5’—-3’. After transcription has occurred, the DNA strands re-form a double helix
Termination
Eventually, the RNA transcript is released, and the polymerase detaches from the DNA
Uracil
one of the four nucleotide bases found in RNA. In DNA, uracil is replaced by thymine (T), but in RNA, uracil takes its place as a key component in the genetic code.
Polyadenylation signal
is a specific sequence of nucleotides in a gene’s DNA that signals where the addition of a poly-A tail should occur on the RNA transcript.
5’ Cap
is a modified nucleotide added to the 5’ end of a newly synthesized messenger RNA (mRNA) molecule in eukaryotic cells shortly after transcription begins.
Poly -A tail
formed by an enzyme that adds 50-250 more adenine (A) nucleotides , added to the 3’ end of a newly synthesized messenger RNA (mRNA) molecule in eukaryotes
Start codon
is a specific sequence of three nucleotides in mRNA that signals the beginning of protein synthesis during translation, not transcription.
Stop codon
Intron
non-coding segments of a gene that are transcribed into RNA but are removed during RNA processing. During RNA splicing, introns are excised, and the remaining exons are joined together to form the mature mRNA.
Exon
segments of a gene that are transcribed into RNA and remain in the final messenger RNA (mRNA) after the RNA processing steps. During RNA splicing, exons are joined together, while non-coding regions called introns are removed.