Question

A protein with $100$ amino acid residues has been translate d based on triplet genetic code, had the genetic code been quadruplet the gene that codes for the protein would have been

• A. same in size
• B. longer in size by 25%
• C. longer in size by 100%
• D. shorter in size

Answer 1

Answer: (B)

Since, the genetic code is a triplet, $64$ triplets of - nucleotides will be involved $(4^3=64)$. If the genetic code is quadruplet it consists of $256$ triplets of nucleotides $(4^4=256)$. $64$ triplets coded for $100$ amino acid residues. So, when $256$ triplets are involved in coding the genes that code for the proteins would have been longer in size by $25\%$.
Calculation $(100\times 256)/64=400$ amino acids.
Hence, the percentage change will be
$(100/400)\times 100=25\%$.
Thus, the correct answer is option (b).