Transcription and the Central Dogma of Molecular Biology Flashcards
central dogma of molecular biology
genetic information flows only in one direction, from
DNA, to RNA, to protein, or RNA directly to protein; first proposed by Francis Crick in 1958
transcription
process by which RNA is produced based on a segment
of DNA
reverse transcription
process of synthesizing DNA using RNA as a template (mechanism used by viruses when they enter host cells)
translation
process by which proteins are produced using RNA molecules as templates
In eukaryotes, transcription
occurs in the
nucleus
In prokaryotes, it occurs in
the
cytoplasm
template strand
strand of DNA that serves as a template for transcription; aka non-coding strand
non-template strand
aka coding strand because sequence is the same as that of the new RNA molecule; will be used to generate a protein during translation
how does rna polymerase know when to start transcription
RNA polymerase binds to the promoter region upstream of the start of transcription
promoter region
a region in DNA having a specific DNA sequence where RNA polymerase first binds to initiate transcription
elongation in prokaryotes
RNA polymerase moves along the DNA template and adds nucleotides to the 3’ end of the growing RNA
termination in prokaryotes
when RNA polymerase reaches the termination site, the RNA transcript is set free from the template
how does rna polymerase know when to stop transcription in bacteria
Hairpin structures form within the
elongating RNA strand to signal the end
of transcription → RNA polymerase and
RNA are released from the DNA
template strand
elongation in eukaryotes
RNA polymerase moves along the DNA
template and adds nucleotides to the 3’ end of
the growing RNA
termination in eukaryotes occurs when
RNA is cleaved downstream of polyadenylation (poly-A) signal
