Exam 2: Transcription & Translation Flashcards
direction of DNA & RNA synthesis
nucleotides added to 3’ end
direction of protein synthesis
new AAs added to c-terminal end
5’ —-> 3’ strand names
sense, coding, + strand
same sequence as mRNA
3’ —- 5’ strand names
anti-sense, template, - strand
replication
DNA from DNA
transcription
RNA from DNA
translation
protein from RNA
transcription unit
region of DNA that can be transcribed into RNA
definite beginning and end (specific nucleotides)
begins in promotor region and ends at terminator
first product of transcription
exact copy of the transcription unit in RNA
in eukaryotes this is the “primary transcript” not mRNA
the primary transcript must undergo…
RNA processing in the nucleus to become mRNA
RNA polymerase
makes RNA form a DNA template
reads 3’ to 5’ creating a 5’ to 3’ sequence of RNA
transcript definition
piece of RNA copied from DNA
product of transcription
how many parts does mRNA have
3
5’ UTR
ORF/CDS
3’ UTS
UTR
untranslated region
5’ called leader sequence
3’ called trailer sequence
ORF/CDS
open reading frame
coding sequence
how many bases are in the ORF
multiple of 3 b/c there are 3 bases per AA code
cap
protects mRNA and helps attach to ribosome
tail
protects mRNA and helps it be exported from nucleus
long string of nucleotides of only Adenine
RNA processing
process of turning primary transcript into mRNA
capping, splicing, polyadenylation
happens in nucleus
spliceosomes
splice introns from 1º transcript
introns are….
regions of extra DNA in transcription units (anywhere)
copied into RNA then spliced out
have no codons
does mRNA have introns?
no
reason for introns
allow eukaryotes to code for more proteins by alternative splicing
ribosomes made of…
mostly RNA, only some protein
an mRNA is ready….
to be translated by ribosomes in the cytoplasm to make proteins
do prokaryotes add caps and tails to mRNA?
no
do prokaryotes have introns and exons?
no
post-transcriptional processing
capping, splicing, polyadenylation
all occurring in the nucleus before mRNA leaves
can eukaryotes have alternate promotors and terminators in the same gene?
yes, allows for more mRNA from same sequence just like introns
