Protein Synthesis

Question 1

What are the 5 steps of protein synthesis?

Answer 1

Activation. Initiation. Elongation. Termination. Posttraslational modifications.

Question 2

What is the structure of tRNA?

Answer 2

Cloverleaf: 3’ end of molecule (CCA sequence), The T psi C loop, D loop, anticodon loop

Question 3

In what loop does the tRNA bind to the ribosome?

Answer 3

T psi C loop

Question 4

Where is the amino acid binding site on tRNA?

Answer 4

3’ end of the molecule

Question 5

Isoacceptor tRNA

Answer 5

Recognize different codons, but all have the same animo acid

Question 6

Amino acyl tRNA synthetases

Answer 6

Couple the amino acid to tRNA via an ester bond. Requires 2 ATP

Question 7

tRNA f met

Answer 7

Initiation codon for prokaryotes

Question 8

What initiation factors bind to 30S subunit?

Answer 8

IF 1 and 3

Question 9

What does IF2 bind to in prokaryotes?

Answer 9

tRNA f met (then binds to AUG at P site)

Question 10

What is the initiation factor essential for lining up the start codon on the ribosome?

Answer 10

eIF-4E (is an mRNA cap binding factor)

Question 11

What is the leader sequence for prokaryotes?

Answer 11

Shine-Dalgarno

Question 12

What determines the efficiency of eukaryotic message translation?

Answer 12

Kozac Consensus Sequence

Question 13

3 stages of elongation

Answer 13

Binding, peptide bond formation, translocation

Question 14

Polycistronic mRNA

Answer 14

One mRNA can code for several proteins, and each one might be translated

Question 15

Polyribosome

Answer 15

Ribosomes + mRNA during translation

Question 16

What does the phosphorylation of eIF-2 do in eukaryotes?

Answer 16

Inhibits translation

Question 17

Cycloheximide

Answer 17

Inhibits peptide bond formation in eukaryotic cells

Question 18

Diphtheria toxin

Answer 18

Catalyzes the reaction of NAD+ w/ eukaryotic elongation factor, resulting in inhibition of translocation

Question 19

Cloramphenicol

Answer 19

Inhibits peptide bond formation, and can inhibit mitochondrial protein synthesis at high levels in both eukaryotes and prokaryotes

Question 20

Puromycin

Answer 20

Causes premature termination in both eukaryotes and prokaryotes

Question 21

Tetracyline

Answer 21

Inhibits elongation in prokaryotes

Question 22

Sreptomycin

Answer 22

Blocks translation in prokaryotes

Question 23

Erythromycin

Answer 23

Inhibits translocation in prokaryotes