NEET · Biology · STD 12 - 9. biotechnology principlas and process

Identify the correct sequence of steps in each cycle of Polymerase Chain Reaction :

A Extension → Annealing → Denaturation
B Annealing → Denaturation → Extension
C Denaturation → Extension → Annealing
D Denaturation → Annealing → Extension

Verified Solution

Answer & Solution

Correct Answer

(D) Denaturation → Annealing → Extension

Step-by-step Solution

Detailed explanation

(D) Denaturation → Annealing → Extension
Polymerase Chain Reaction (PCR) involves three main steps in each cycle:
Denaturation: The double-stranded DNA is heated to a high temperature (around \(94^{\circ} C\)) to break the hydrogen bonds, resulting in two single strands.
Annealing: The temperature is lowered (around \(50^{\circ} C\) to \(65^{\circ} C\)) to allow the primers to bind to the complementary sequences on the single-stranded DNA.
Extension: The temperature is raised (around \(72^{\circ} C\)) to allow Taq polymerase to synthesize the new DNA strand by adding nucleotides to the primers.
Thus, the correct sequence is Denaturation → Annealing → Extension.

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Match List \(I\) with List \(II\)

List \(I\)	List \(II\)
\(A\). Two or more alternative forms of a gene	\(I\). Backcross
\(B\). Cross of \(F_1\) progeny with homozygous recessive parents	\(II\). ploidy
\(C\). Cross of \(F_1\) progeny with any of the parents	\(III\). Allele
\(D\). Number of chromosome sets in plant	\(IV\). Test cross

Choose the correct answer from the options given below:

NEET 2024 Medium

Explore more questions on app

From NEET

Explore more questions on app