CBSE 2026 · Region 2 · Set 2 · Q25 · 3 marks
(a)What is a genetic code?(b)Why did scientists feel the need to propose a genetic code?(c)Genetic code is said to be 'Universal'. Why?
(a)
What is a genetic code?
(b)
Why did scientists feel the need to propose a genetic code?
(c)
Genetic code is said to be 'Universal'. Why?
Marking-scheme solution
(a)
Genetic Code: It is the sequence of three nitrogenous bases (codon) on mRNA that directs the sequence of amino acids during synthesis of proteins.
(b)
To provide complementarity between nucleotides and amino acids / to support the notion that change in nucleic acids was responsible for change in amino acids in proteins / to establish the correlation between genetic information and protein synthesis / to constitute a combination of four bases to code twenty amino acids.
(c)
As a codon from bacteria to human code for the same amino acid.
Molecular Basis of InheritanceGenetic CodeUnderstandshort_answereasy
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CBSE Class 12 Biology past-paper question from the 2026board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.