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Biochem Ch. 40.1-40.4
Biochem Ch. 40.1-40.4
56
Biochemistry
Undergraduate 3
04/02/2018

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Term
the 3 parts of protein synthesis
Definition
1: initiation
2: elongation
3: termination
Term
protein-synthesis initiation requires the the cooperation of...
Definition
-the ribosome
-tRNA
-mRNA
-various protein factors
Term
the 3 tRNA binding sites in ribosomes
Definition
-A site (aminoacyl)
-P site (peptidyl)
-E site (exit)
Term
depiction of the binding sites of transfer RNA
Definition
refer to p. 722
Term
depiction of an active ribosome
Definition
refer to p. 722
Term
the start signal for translation is usually...
Definition
AUG
Term
polycistronic
Definition
when an mRNA encodes 2 or more polypeptide chains
Term
all known mRNA molecules contain...
Definition
the start and stop signals of the polypeptide chain(s) they encode
Term
other than the initiating codon, what else is involved in initiation in bacteria?
Definition
a purine-rich sequence called the Shine-Dalgarno sequence
Term
Shine-Dalgarno sequence
Definition
purine-rich sequence upstream of start codon that helps initiate translation
Term
depiction of initiation sites
Definition
refer to p. 723
Term
function of untranslated regions of mRNA
Definition
usually to regulate the usage of mRNA molecules
Term
the 2 kinds of interactions that determine where protein synthesis starts in bacteria
Definition
1: pairing of mRNA bases with the 3' end of 16S rRNA
2: pairing of the initiator codon on mRNA with the anticodon of an initiator tRNA molecule
Term
bacterial protein synthesis is initiated by...
Definition
formylmethionyl tRNA
Term
protein synthesis in bacteria starts with...
Definition
the modified amino acid N-formylmethionine (fMet)
Term
depiction of N-formylmethionine (fMet)
Definition
refer to p. 723
Term
depiction of the formylation of methionyl-tRNA
Definition
refer to p. 723
Term
the rate-limiting step in protein synthesis
Definition
formation of the 70S complex
Term
depiction of translation initiation in bacteria
Definition
refer to p. 724
Term
reading frame
Definition
basically where the ribosome reads the mRNA
Term
elongation factors
Definition
deliver aminoacyl-tRNA to the ribosome
Term
accommodation
Definition
rotation of the aminoacyl-tRNA in the A site so that the amino acid is brought into proximity with the aminoacyl-tRNA in the P site on the ribosome

this process aligns the amino acids for peptide bond formation
Term
are internal AUG codons read by the initiator tRNA?
Definition
no
Term
peptidyl transferase center
Definition
catalyzes the formation of a peptide bond
Term
the ribosome gets much of its catalytic power from...
Definition
catalysis by proximity and orientation
Term
depiction of peptide bond formation
Definition
refer to p. 726
Term
depiction of the mechanism of protein synthesis
Definition
refer to p. 726
Term
translocation in ribosomes is enhanced by...
Definition
elongation factor G (EF-G) aka translocase
Term
elongation factor G (EF-G) aka translocase
Definition
enhances elongation in ribosomes
Term
depiction of the translocation mechanism
Definition
refer to p. 727
Term
where the peptide chain stays during translation
Definition
in the P site of the ribosome; it leaves thru the exit tunnel
Term
how tRNA moves thru the ribosome
Definition
in the A site, thru the P site, and out the E site
Term
direction the polypeptide chain is synthesized in
Definition
amino-terminal-to-carboxyl-terminal
Term
depiction of polypeptide chain growth
Definition
refer to p. 727
Term
which terminus are new amino acids added to in protein synthesis?
Definition
carboxyl terminus
Term
protein synthesis is terminated by...
Definition
release factors that read stop codons
Term
stop codons are recognized by...
Definition
release factors (RFs)
Term
depiction of the termination of protein synthesis
Definition
refer to p. 728
Term
what a release factor does
Definition
recognizes a stop codon in the A site and stimulates the release of the completed protein from the tRNA in the P site
Term
where bacteria and eukaryotes differ in protein synthesis
Definition
initiation
Term
some areas where bacteria and eukaryotes differ in the initiation of protein synthesis
Definition
1: ribosomes
2: initiator tRNA
3: initiation
4: the structure of mRNA
5: elongation and termination
6: organization
Term
difference between bacterial and eukaryotic ribosomes
Definition
eukaryotic ribosomes are larger
Term
difference in initiator tRNA between bacteria and eukaryotes
Definition
-the initiator in bacteria is N-formylmethionine
-the initiator in eukaryotes is methionine
Term
the initiating amino acid in bacteria
Definition
N-formylmethionine
Term
the initiating amino acid in eukaryotes
Definition
methionine
Term
the initiating codon in eukaryotes
Definition
always AUG
Term
initiation in eukaryotes begins with...
Definition
the formation of the ternary complex consisting of the 40S ribosome and Met-tRNAi in association with eIF-2
Term
why a bacterial mRNA can serve as the template for the synthesis of several proteins
Definition
because it can have multiple Shine-Dalgarno sequences, thus multiple start sites, making it able to serve as the template for multiple proteins
Term
part of the reason the initiation mechanisms between bacteria and eukaryotes are different
Definition
difference in RNA processing
Term
depiction of eukaryotic translation initiation
Definition
refer to p. 729
Term
the shape of eukaryotic mRNA
Definition
circular
Term
depiction of how protein interactions circularize eukaryotic mRNA
Definition
refer to p. 729
Term
how the translation machinery is organized in higher eukaryotes
Definition
organized into large complexes associated with the cytoskeleton
Term
some antibiotic inhibitors of protein synthesis
Definition
-streptomycin and other aminoglycosides
-tetracycline
-chloramphenicol
-cycloheximide
-erythromycin
-puromycin
Term
table of antibiotic inhibitors of protein synthesis
Definition
refer to p. 731
Term
depiction of the antibiotic action of puromycin
Definition
refer to p. 731
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