Question

If there are 999 bases in an RNA that codes for a protein with 333 amino acids, and the bases at position 901 are detected such that the length of the RNA becomes 998 bases, how many codons will be altered?
(a) 333
(b) 1
(c)11
(d) 33

Answer 1

Hint: We know that 1 codon consists of three bases, usually corresponding to a single amino acid. there is a deletion happening in the base at the 901st position. Subsequently, there will be a change just in the last 99 bases and there will be no adjustment in the initial 900 bases.

Complete answer:
For 333 amino acids, 999 bases in RNA codes for a protein. On the off chance that the base at 901 positions is erased, at that point, the initial 900 bases will be ordinary while bases after the 901st base will be modified, that is 99 bases will be changed.
3 bases represent 1 codon, in this way, 99 bases = 33 codons will be changed because of the cancellation of one base at 901 positions.

Additional Information: At the point when translation starts, the small subunit of the ribosome and an initiator tRNA molecule gather on the mRNA transcript. In the ribosome, there is a small subunit of the three binding sites: an amino acid site (A), a polypeptide site (P), and an exit site (E). For conveying the amino acid, in the initiator tRNA molecule, the methionine binds to the AUG start codon of the mRNA transcript at the ribosome’s P site where it will become the first amino acid that will bind into the growing polypeptide chain.
So the correct answer is ‘33’.

Note: The initiator methionine tRNA is the main aminoacyl-tRNA that can bind in the P site of the ribosome, and the A site is aligned with the second mRNA codon. At the second aminoacyl-tRNA at the A site, the ribosome is consequently prepared to bind which will be joined to the initiator methionine by the first peptide bond.