Class 12 · Molecular Basis of Inheritance

Universality of Genetic Code — NEET Biology

✅ Asked in NEET 2023
📖 NCERT Source

The code is nearly universal: for example, from bacteria to human UUU would code for Phenylalanine (phe). Some exceptions to this rule have been found in mitochondrial codons, and in some protozoans.

NCERT Biology · Class 12 · Chapter 5 · Paragraph 96
How NTA Uses This Concept

The genetic code is nearly universal across organisms, meaning the same codon (like UUU) codes for the same amino acid (Phenylalanine) in bacteria, plants, and humans. This universality is one of the key features proving all life shares a common genetic basis. Students often mistakenly think the code is absolutely universal with zero exceptions, but NEET tests the word 'nearly'—there ARE exceptions in mitochondrial DNA and some protozoans due to codon reassignment. Remember: universal ≠ absolutely universal; always account for rare exceptions in special organelles and organisms to avoid falling into trap answers.

Solve This NEET Question

This paragraph was tested 2 times in NEET.

Q1 of 2NEET 2023

The salient features of genetic code include: (NEET 2023) (A) The code is palindromic (B) UGA acts as initiator codon (C) The code is unambiguous and specific (D) The code is nearly universal Choose the correct option:

Q2 of 2NEET 2019

Which feature of genetic code allows bacteria to produce human insulin via rDNA technology? (NEET 2019)

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