Transcription, Genetic Code, Translation Flashcards
Element found downstream of the transcription start site (Pribnow box and -35 in eukaryotes; TATA box, CAAT box, GC box in eukaryotes)
Promoter
Promoter, -10 nt downstream of tss (prokaryotes)
Pribnow Box
Promoter, -30 to -100 bp downstream of tss (eukaryotes)
TATA box
Element that increases transcription, found 1000s of nt’s downstream of tss (eukaryotes)
Enhancer
An enhancer element that is responsive to regulation from an environmental stimuli, for example hormones or metals (eukaryotes)
Response element
Trans-acting protein that binds to promoter or initiator site to promote transcription (eukaryotes)
Transcription factor
Synthesizes single rRNA transcript (eukaryotes)
RNA Pol I
Transcribes tRNAs and 5S rRNA (eukaryotes)
RNA Pol II
Transcribes mRNA (eukaryotes)
RNA Pol III
Regulatory subunit of RNA polymerase, binds -35 region (prokaryotes)
Sigma factor
Multi-protein coding genetic cassette under regulation (prokaryotes)
Operon
Binds operator site of operon and prevents transcription (prokaryotes)
Repressor
Binds and inactivates repressor (allolactose in lac operon, prokaryotes)
Inducer
Un-translated region of RNA that is removed by splicing
Intron
Expressed region of RNA that remains after splicing
Exon
Adenosine nucleotide in the center of an intron, U2 binds here
Branch Site
Splicing intermediate after the first splicing reaction occurs, cyclic intermediate connecting 5’-end of intron to the branch site
Lariat
Ribonucleoprotein subunit involved in mRNA processing through splicing
snRNP
Write out the chemical equations for the two steps in the reaction catalyzed by aminoacyl tRNA transferase. Include all products and reactants.
Step 1: amino acid activation
Step 2: aminoacyl transfer to the tRNA
amino acid + ATP → aminoacyl-AMP + PPi
aminoacyl-AMP + tRNA → aminoacyl-tRNA + AMP
Write the chemical equation for the net reaction catalyzed by aminoacyl transferase.
amino acid + ATP + tRNA → aminoacyl-tRNA + AMP + 2Pi
“Coding center” where mRNA pairs with tRNA anti-codon end
30S subunit
“Catalytic center” where aminoacyl end of tRNA binds and the peptide chain is synthesized
50S subunit
GTPase which shifts register of tRNAs from A-P sites to P-E sites, uses GTP
EF-G
Utilizes GTP to recruit charged tRNAs to the A site of the ribosome
EF-Tu
Binds A site to prevent premature ribosomal assembly
IF-1
GTPase which guides initiator tRNA to the 30S ribosomal pre-initiation complex
IF-2
Binds E site to prevent premature ribosomal assembly
IF-3
Binds A site when a stop codon is present on the mRNA, ends translation
RF-1
Charges tRNAs with activated amino acids
Aminoacyl tRNA synthetase
3 nt sequence on tRNA that is reverse complement to codon
Anticodon
3 nt sequence on mRNA which codes for an amino acid
Codon
1st base of the anticodon (3rd base of the codon) has more flexibility in base pairing, leads to degeneracy in codons
Wobble Hypothesis
Purine rich sequence downstream of start codon which binds to 16S rRNA of 30S subunit to initiate translation
Shine-Delgarno Sequence
The ribosome has three sites for binding tRNAs. What are they?
A site:
- “Aminoacyl site”
- where charged tRNAs enter
P site:
- “Peptidyl site”
- Where the growing peptidyl chain is found
E site:
- “Exit site”
- Where the uncharged tRNAs exit
