Practice question

MCQ

Question

Har Gobind Khorana and Marshall Nirenberg elucidated the genetic code by using a cell-free protein synthesizing system. It was found that poly(U) and poly(C) result in the synthesis of poly(L-Phe) and poly(L-Pro), respectively. Based on these observations, which one of the following conclusions is correct?

Options

Choose one · Correct answer highlighted

Codon GGG specifies L-Phe and codon AAA specifies L-Pro Codon CCC specifies L-Phe and codon UUU specifies L-Pro Codon AAA specifies L-Phe and codon GGG specifies L-Pro Codon UUU specifies L-Phe and codon CCC specifies L-Pro Correct

Explanation

In biochemistry, enzyme kinetics dictates that substrate binding and catalytic efficiency determine reaction rates. Therefore Codon UUU specifies L-Phe and codon CCC specifies L-Pro is correct as it reflects active-site specificity and regulation, supported by mechanistic studies and conserved across related systems.

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