The average amino acid length of proteins in Escherichia coli is 235. Therefore, according to the video, the elongation time for an average E. coli protein would be about seconds. How is the small ribosomal unit positioned to allow for translation to start at the proper start codon?Choose one:
A. Shine-Dalgarno sequence
B. The start codon sequence is specifically attracted to the P site.
C. Initiation factors position the mRNA accordingly.
D. The small ribosomal subunit starts at the far 5' end of mRNA where the start codon is located.

approximately 15 seconds

A. Shine-Dalgarno sequence

Explanation:

In Escherichia coli, it has been shown that the translation elongation rate is approximately 16 amino acids per ribosome per second (16 x 15 = 240). On the other hand, the Shine-Dalgarno sequence is a polypurine stretch of variable length present in prokaryotic cells and acts as a ribosomal binding site for the messenger RNA (mRNA). This sequence can base-pair to a complementary sequence known as the 'anti-Shine-Dalgarno sequence' at the 3' end of the bacterial 16S rRNA subunit and is required to initiate the process of translation by which a polypeptide chain is synthesized. Generally, the Shine-Dalgarno sequence is located from 10 to 8 nucleotides upstream of the start codon (AUG codon). In E. coli, the Shine-Dalgarno sequence is AGGAGGU.

they deliver oxygen to the blood