Transcription Flashcards
DNA is found inside the
nucleus
Proteins, however, are made in the cytoplasm of cells by organelles called
ribosomes
DNA‘s code must be copied and taken to the
cytosol
In the cytoplasm, this code must be read so amino acids can be assembled to make
polypeptides (proteins)
The process of copying the sequence of one strand of DNA, the template strand
Transcription
What copies the template strand ?
mRNA
Transcription requires the enzyme______
RNA Polymerase
In transcription, part of DNA temporarily unzips and is used as a template to assemble complementary nucleotides into
messenger RNA (mRNA)
identifies gene start and end points on the DNA to initiate and terminate transcription.
RNA polymerase
What is the only enzyme in transcription?
RNA polymerase
recognizes the correct DNA strand to avoid transcribing non-informative DNA strands.
RNA polymerase
Recognition of initiation and termination sequences in DNA allows________ to perform these tasks effectively.
RNA polymerase
RNA polymerase binds to the DNA of the gene at a region called the
promoter
contain the information for transcription initiation and are the major sites in which gene expression is controlled
promoter
a DNA sequence that indicates where a genetic sequence can be read and decoded
TATA Box
is a protein that binds to specific DNA sequences, thereby controlling the rate of transcription of genetic information from DNA to messenger RNA
Transcription Factor
stabilize or block the binding of RNA polymerase to DNA
Transcription Factor
control when, where, and how efficiently RNA polymerases function
Transcription Factor
Termination of transcription comes about when the polymerase enzyme recognizes a DNA region known as a
terminator sequence
marks the end of a gene transcription
Termination sequence
signals to the RNA polymerase enzyme that the gene has been fully transcribed into a strand of RNA
Termination signal
80%
Major component of the ribosomes; site of protein synthesis
Ribosomal RNA
rRNA
5%
Carries information for protein synthesis from the DNA to the ribosomes
Messenger RNA
mRNA
15%
Brings specific amino acids to the site of protein synthesis
Transfer RNA
tRNA
Pre-mRNA
Heterogeneous nuclear RNA
hnRNA
RNA formed directly by DNA transcription
Heterogeneous nuclear RNA (hnRNA)
Post-transcription processing converts the heterogeneous nuclear RNA to
messenger RNA
RNA that facilitates the conversion of heterogeneous nuclear RNA to messenger RNA
It contains from _____ to ____ nucleotides
Small nuclear RNA (snRNA)
100 to 200
Component of splicesosome
Small nuclear RNA (snRNA)
Splicesosome
Gets rid of introns
hRNA to actual mRNA
Addition of a 5’ cap to the beginning of the RNA (________)
RNA capping
(tail of A nucleotides)
poly-A tail
Addition of a poly-A tail (tail of A nucleotides) to the end of the RNA
polyadenylation
added to the first nucleotide in the transcript during transcription
a modified guanine nucleotide
protects the transcript from being broken down
used as a recognition signal for ribosomes to bind to the mRNA
5’ cap
Poly-A tail
AAAA to 3’ end of RNA transcript are added (polyadenylation)
plays a role in the stability of the mRNA
3’ tail
is the process of removing introns from an hnRNA molecule and joining the remaining exons together to form an mRNA molecule
RNA splicing
a gene segment that conveys (codes for) genetic information
is a gene segment that does not convey (code for) genetic information
Exons
Introns
