Question
NEET 2022 (paraphrased): Regarding protein synthesis, which of the following statements is correct? (a) codon refers to AUG, codes for methionine (b) start codon is characterised by 3 nucleotides = 1 amino acid (c) stop codons — UAA, UAG, UGA (d) ribosome has no role in protein synthesis
Solution — Step by Step
This option swaps the definitions. codon is actually 3 nucleotides = 1 amino acid, not what (a) claims. So (a) is out.
Similarly, start codon means AUG, codes for methionine. Option (b) is mismatched. Out.
This one reads correctly: stop codons — UAA, UAG, UGA. Match with NCERT wording confirms it.
ribosome — site of translation; has large and small subunits — plays a real role in protein synthesis, so option (d) is factually wrong.
Correct answer: (c) stop codons — UAA, UAG, UGA.
Why This Works
NEET PYQs on protein synthesis rely on definition swapping. The examiner takes two correct facts and pairs them with the wrong terms. If you know each fact cold, the MCQ dissolves in 20 seconds.
Alternative Method
For definition-swap MCQs, don’t read all four options first. Read option (a), decide true/false, then (b), and so on. This prevents confusion between similar-looking options.
NEET reuses the same fact set every 2–3 years with different distractors. Master the four NCERT facts on protein synthesis listed here and you’ll handle almost any MCQ on this chapter.
Common Mistake
Students second-guess themselves when they see a familiar option listed as “wrong” in the stem. Trust the elimination — if you know the definition, stick with it.
Keep a one-page sheet of definitions for every NEET chapter. Revise only that sheet in the last 48 hours before the exam.