Ch 9 Flashcards
Process of DNA replication
DNA gyrase. Relaxes super coiling.
DNA, helicase case unzips the DNA helix
Primase makes a small RNA primer for DNA polymerase
DNA polymerase adds complementary nucleotides
DNA ligase joins DNA fragments of the lagging strand
Transcription
Making double-stranded m-rna from DNA template (gene)
RNA polymerase attaches to
Promoter [tata box] which is upstream of the gene
Steps of Transcription
Initiation, elongation, termination
Prokaryotic mRNA can
Code for
mRNA is a
Temporary copy of information in DNA
Translation
mRNA to protein
mRNA uses
3 - letter codons
Start codon
AUG
Stop codon
UAG,UAA,UGA
Redundancy
Genetic code is degenerative
Translation needs
mRNA, tRNA, ribosome,
Sites in ribosome
A, amino acid has dropped off at the acceptor site
P, peptide is built
E exit site 
Initiation
Ribosome binds to site (A)
AUG is start codon the complete ribosome assembles at the start codon
Elongation
Initiating tRNA still occupies p - site
Second tRNA with its amino acids elongation phase creates a polypeptide proteins
Termination
mRNA stop codon stops translation polypeptide gets released from the ribosome by enzymes.
Added Base pairs
Can make an incorrect reading frame base pair likely nonfunctional protein
Post translational modifications
Polypeptide modified after synthesis
Some must be folded into specific three-dimensional structure with assistance of proteins chaperones
Such as phosphorylation glycosylation methylation 
Prokaryote transcription & translation
70s ribosome ( 30s+50s )
Simultaneous transcription & translation in bacteria
MRNA can be polycistronic
Eukaryotes translation & transcription
80s ribosome (40s + 60s )
Non-coding sequence is our introns spicing removes introns
Exons are expressed regions
MRNA transported to cytoplasm
MRNA typically monocistronic
TRNA
Contains an anti-codon that is complementary to the mRNA codon you binds to a G binds to see
TRNA brings the correct amino acid to the building proteins
