Which of the following is a correct sequence of steps in a PCR (Polymerase Chain Reaction) ?
Answer: (C) Denaturation, Annealing, Extension. Answer: (C) Denaturation, Annealing, Extension Solution: Each cycle of PCR has three steps in fixed order: denaturation (separation of double-stranded DNA at high temperature), primer annealing (primers bind complementary regions), and extension of primers by DNA polymerase.
- A.Extension, Denaturation, Annealing
- B.Annealing, Denaturation, Extension
- C.Denaturation, Annealing, Extension✓
- D.Denaturation, Extension, Annealing
Correct Answer
(C) Denaturation, Annealing, Extension
Solution & Explanation
Answer: (C) Denaturation, Annealing, Extension Solution: Each cycle of PCR has three steps in fixed order: denaturation (separation of double-stranded DNA at high temperature), primer annealing (primers bind complementary regions), and extension of primers by DNA polymerase. This cyclic order amplifies the gene of interest. NCERT Reference: Ch 9, p.172, line(s) 19 — "Polymerase chain reaction (PCR) : Each cycle has three steps: (i) Denaturation;"