| Question |
Answer |
| What enzyme joins amino acids to the correct tRNA? |
aminoacyl-tRNA-synthetases |
| What end of the tRNA does the amino acid join to? 3' or 5' |
3' |
| What kind of linkage joins the amino acid to the tRNA molecule? |
ester |
| What stop codon can sometimes specify seleno cysteine? |
UGA |
| What AA is sometimes called the 21st AA? |
selenocysteine |
| What special sequence requires a stem-loop forming sequence downstream of a UGA codon? |
Selenocysteine Insertion Sequence |
| What is the number of small subunits for higher level organisms? |
40S |
| What is the first codon used in most protein synthesis? |
AUG |
| What AA does AUG code for? |
Met |
| What is eIF2? Function? |
eukaryotic initiation factor 2; binds tRNAiMet to small subunit |
| What is the "Kozak" consesus? |
PuPyPyAUGG; favorable start codon |
| What does eIF4 do? |
caps the 5' end |
| What is the Shine-Dalgarno sequence? |
upstream sequence to a start codon that can base pair to 3' end of 16S RNA |
| What is the P-site? |
peptide chain bound to the last tRNA |
| WHat is the A-Site? |
aminoacyl-tRNA |
| What two things are required for binding an incoming charged tRNA? |
hydrolysis of GTP and elongation factors |
| What is peptide bond formation catalyzed by? |
28S rRNA |
| What two things are required for the A-site to move to the P-site? |
GTP hydrolysis and EF2 |
| How does the peptide chain terminate in the P-site? |
stop codons, special release factors bind |
| From what end to what end is the mRNA read? |
5' to 3' |
| From what end to what end is the protein synthesized? |
from amino to carboxyl end |
| Peptidyl transferase reside on what rRNA? |
28S |
| What is the term for multiple ribosomes working on a single mRNA? |
polysomes |
| What are the 2 times of chaperones? |
Hsp 60 and Hsp 70 |
| What are function of Hsp 70's? |
BiP - major ER chaperone |
| What is another name of Hsp 60? |
chaperonins; in mitochondrial matrix; example is GroEL |
| What is the chaperone mechanism? |
bind and release hydrophobic regions until all are buried inside of the protein |
| What inhibits pro and eukaryote protein synthesis? |
puromycin |
| What inhibits peptidyl transferase in eukaryotes? |
cycloheximidine |
| What inihbits protein synthesis initiation and causes misreading in prokaryotes? |
Streptomycin |
| What inhibits binding of tRNA to 30s subunit? |
tetracycline |
| What inhibits peptidyl transferase in 50s subunits in prokaryotes? |
chloramphenicol |
| What binds to 50s subunits and inhibits translocation in prokaryotes? |
erythromycin |
Ch.18 LTI-MA 509
