Quiz 4 study deck Flashcards
(34 cards)
Where is the amino acid attachment site on tRNA
3’ end
What part of the amino acid attaches to the tRNA
the carboxyl
What does aminoacyl-tRNA synthetase do
recognizes specific AA
How much energy does translation use
a lot- major consumer of Energy (need to cleave 4 high-energy bonds)
Describe the antiparallel nature of codon recognition and binding
mRNA codon is read 5’-3’ by an anticodon that pairs 3’-5’
Where does translation take place
on the ribosomes
What are the 4 stages of protein synthesis
tRNA charging, initiation, elongation, termination
What are the 3 steps of initiation
mRNA binds to subunit of ribosome, initiator tRNA binds to mRNA, large ribosome joins complex
What does elongation require
70s complex, charged tRNAs, elongation factors, GTP
What 3 sites do ribosomes have
APE
Steps in elongation
charged tRNA binds to A site, forms peptide bond between A-P site, translocation
When does termination occu
when a ribosome translocates to a termination codon
What level does most gene regulation occur at
at a transcriptoinal level usually
Contranslational modifications vs posttranslational modifications
contranslational: changes to proteins while still attached to ribosome
posttranslational: changes to protein after synthesis is done
Are translated sequences removed the same way or different ways?
Translated sequences are trimmed by many different enzymes and by with many different chemical groups
What is a common way that proteins are degraded
ubiquitination- label proteins for cellular destruction and rapid degredation
What is the primary site of regulation in both prokaryotes and eukaryotes
transcription
What are the regulatory elements
- Regulatory genes
-Regulatory elements (DNA sequences that aren’t transcribed)
-Constitutive genes
What is an operon
group of bacterial genes that are transcribed together (often into a single mRNA)
Negative vs positive control of an operon
Negative: regulatory protein is a repressor
Positive: Regulatory protein is an activator
Describe lactose transport in bacteria
Glucose is preferred by bacteria over lactose, but repressor will bind to operator when need to use lactose for fuel
Is lactose in the lac operon an inducer or repressor
Lactose is the inducer and releases the repressor
What type of operon is Trp
Negative repressible (encode a reperssor that cannot bind to DNA without activator)
When Trp levels are high, trp binds to repressor and activates, halts transcription
What is the stringent response
due to lack of amino acids, leads to inhibition of rRNA synthesis
