Transcription and translation Flashcards
dna
has two strands making a double helix
what is a single strand composed of
4 types of nucleotides; building blocks of dna
nucleotide components
suagr
phosphate
nucleobase
how do nucleotides of one strand pair up with the other
via hydrogen bonds
how does the coding strand run
5’ to 3’
how does the template strand run
3’ to 5’
how does transxription start
unpacking of DNA from chromatin and de-helicization - meaning that the double helix unwinds a bit so that individual genes are exposed
how is the start point of a gene determined
by a promotor region
what is a promotor region
repetitive non-coding sequence of nucleotides
TATA box
famous promotor
marks where to start transciribing
pre initiation complex
proteins come together around the promoter featuring an enzyme called polymerase
elogation
rna polyermase unzips the two strands by shearing the hydorgen bonds between the complementary nucleotides
action of rna polymerase
polymerase follows the template strand and uses it to assemble an mRNA molecule, that is the mirrored image of the template strand
how does mrna differ from dna
t replaced with uracil
how does mrna run
5’ to 3’
how does rna move along
3’ to 5’
what does rna do to mrna
attaches complemetary nucleotides
if the leading strand is AATCCAGTA what is the template and mrna strand
template; T T A G G T C A T
mrna; A A U C C A G U A
what happens as rna polymerase goes down the dna
zips the dna back together nearer the end
terminator sequence
where the rna polymerase eventually reaches
contains two complimentary sequences in a row
what makes the rna polymerase detach from dna strand
when the terminator sequence gets transcribed into mrna and the seuqnces bond with each other causing termination
termination
mrna detaches from enzyme
dna closes back up
rn goes off to transcirbe aother
spliceosome
splices intorns out of mrna
exons
coding regions
intorns
non coding
how does the mrna get out of the nucelus
through a pore and hooks up with an idle ribosome to beign translation
initiation
ribosome grabs mrna
codon
groups of 3 letters
what does a codon code for
amino acid
how does the irbsoome start
start codon- usually AUG
when does translation continue until
stop codon also known as termination
trna
takes amino acid to ribosome
anticodon
trna
complementary to mrna so can bind and deposit amino acid in ribosome
3 binding sites of ribosome for trna to bind
aminoacyl site
peptidly site
exit site
what begins translation
trna binding to p site with methionine; AUG
what binds to A site
amino acid-carrying tRNA with the complementary codon for the mRNA
peptide bond role
hoolds growing protein together
where does a peptide bond form
between the amino acid of the tRNA in the A-site and the amino acid of the charged tRNA in the P-site
where is the growing polyp chain transferred to
a site
how is the process repeated
trna with polyp chain moves to p site and so a site becomes open for a new trna to bring another AA
final part of translation
ribosome carrying its fresh protein to endoplasmic reticulum
