Protein Synthesis Flashcards
Transcription
process of making mRNA from a gene
What do we need for transcription?
- Template
- Initiation
- Separation of strands
- Polymerase activity
- Termination
Sense
non-template (coding) strand
reads 5’ to 3’
the same as mRNA strand except for T instead of U
Anti-sense
template strand
reads 3’ to 5’
complimentary to mRNA and sense strand
Which direction is RNA built in?
5’ to 3’ direction
Sigma factor
part of protein complex that initiates the process by binding directly to DNA
recognizes and binds to the promoter
Do promoters vary?
Yes, but they all are similar so that sigma factor can recognize
Does the promoter get copied?
No
Location where transcription begins?
+1
RNA polymerase
elongates
Termination phase
termination sequence codes RNA which will create a hairpin in the mRNA
Is the terminator sequence transcribed?
It has to be because it codes for the hairpin
Transcription in eukaryotes
diverse promoters
TATA box
basal transcription factors
TATA box
found in eukaryotes
30 boxes upstream
promoter sequence
Basal transcription factors
found in eukaryotes
bind to DNA promoter and initiate transcription
Transcription in prokaryotes
can have simultaneous transcription and translation since no nucleus
What is an evolutionary advantage that prokaryotes have?
They are able to metabollically adapt very quickly to new conditions and produce new proteins
Post transcriptional controls
splicing
add non-coding regions to protect
help interact with ribosome
Translation
mRNA is converted to an amino acid sequence in a protein
3 phases of translation
- initiation
- elongation
- termination
Ribosomes
catalyze translation of the mRNA sequence into protein
A site
the acceptor site for an aminoacyl tRNA
P site
where a peptide bond forms that adds an amino acid to the growing polypeptide chain
E site
where tRNAs no longer bond to an amino acid exit the ribosome
Order of the sites
EPA
tRNA
CCA sequence at 3’ end binds to amino acid
anticodon base pairs with the mRNA codon
shaped like upside down L
redundancy in protein synthesis
multiple codons code for the same amino acid
redundancy in protein synthesis
multiple codons code for the same amino acid
Where do tRNAs vary?
Different anticodons and amino acids
