Protein synthesis and processing 2

Question 1

What are the steps of initiation of transition in eukaryotic cells?

Answer 1

Step 1: The 40S ribosomal subunit, various initiation factors (eiFs),
Step 2: The 40S/ tRNAmet/ eIF complex meets up with a mature mRNA& binds to the 5’m7G cap.
Step 3: The entire complex slides along the mRNA until it finds the AUG start codon
Step 4: Most of the complex (except
met
for 40S subunit & tRNA ) dissociates
from start site & 60S rib s.u attaches

Question 2

What are the 3 steps in specificity of amino acid incorporation during Translation?

Answer 2

(1) contains an anticodon which will match the correct mRNA codon, 2) brings correct amino acid to the ribosome
(3) Decoding centre within 40s ribosomal Subunit ensures proper aminocacyl tRNA pairs with codon

Question 3

What are the steps in elongation in eukaryotic cells?

Answer 3

Step 1: tRNAmet / ribosome complex is sitting at AUGstart site of mRNA (&P site of ribosome).
Step 2: the next c harged tRNA comes to A site
Step 3: peptide bond formation between amino acids
Step 4: ribosome moves downstream ( = tRNA moves from A site to P site)
Step 5: repeat steps 2-4

Question 4

What are the steps in termination in eukaryotic cells?

Answer 4

Step 1: stop signal (codon) in A site.
Step 2:releasing factor in A site.
Step 3: poly- peptide chain released
Step 4: ribosome disassembly