Module 8 Part 2

•requires ribosomal subunits assembled with the mRNA to form the P (peptidyl) site and A (aminoacyl) sites.

•The charged tRNAs enter the A site, and ________ ___________ catalyzes peptide bond formation between the amino acid on the A site and the P site.

Which step in elongation?

• Second charged tRNA has entered A site, facilitated by EF-Tu

• First peptide bond forms; uncharged tRNA moves to the E site and subsequently out of the ribosome;

• the mRNA has been translocated 3 bases to the left, causing the tRNA bearing the dipeptide to shift into the P site

• first elongation step is complete, facilitated by EF-G. The third charged tRNA is ready to enter the A site.

Which step in elongation?

• Second charged tRNA has entered A site, facilitated by EF-Tu

• First peptide bond forms; uncharged tRNA moves to the E site and subsequently out of the ribosome;

• the mRNA has been translocated 3 bases to the left, causing the tRNA bearing the dipeptide to shift into the P site

• first elongation step is complete, facilitated by EF-G. The third charged tRNA is ready to enter the A site.

Which step in elongation?

• Second charged tRNA has entered A site, facilitated by EF-Tu

• First peptide bond forms; uncharged tRNA moves to the E site and subsequently out of the ribosome;

• the mRNA has been translocated 3 bases to the left, causing the tRNA bearing the dipeptide to shift into the P site

• first elongation step is complete, facilitated by EF-G. The third charged tRNA is ready to enter the A site.

•forms by a dehydration reaction between the carboxyl group of one amino acid and the amino group of another.

Two amino acids joined together to form a

The small ribosomal unit is responsible for what action during elongation?

• Decoding the triplets present in mRNA

• Transcribing DNA into mRNA
• Initiating protein synthesis
• Releasing the completed polypeptide chain

The large ribosomal unit is responsible for what action during elongation?

• Decoding the triplets present in mRNA

• Peptide bond synthesis

• Initiating protein synthesis
• Releasing the completed polypeptide chain

What are the stop codons?

• UAG

• UGA

• UAA

• UGG