PCR and the steps of recombinant DNA technology — NEET & JEE Questions

Question 1 · difficulty L1 · recall

PCR is primarily used to

• A. amplify a selected DNA sequence
• B. separate proteins by mass
• C. translate DNA into protein
• D. destroy all template DNA

Question 2 · difficulty L2 · understanding

Polymerase chain reaction (PCR) amplifies DNA following the equation.

• A. $2 n+1$
• B. $2 \mathrm{~N}^2$
• C. $\mathrm{N}^2$
• D. $2^n$

Question 3 · difficulty L2 · understanding

During PCR, what happens during the annealing step?

• A. Restriction enzymes cut the amplified DNA
• B. DNA strands are separated by high temperature
• C. DNA polymerase synthesises new strands at maximum temperature
• D. Primers bind to complementary sequences on the template DNA

Question 4 · difficulty L2 · understanding

During PCR, the denaturation step mainly

• A. separates the two DNA strands
• B. allows primers to bind
• C. extends primers with DNA polymerase
• D. ligates vector and insert

Question 5 · difficulty L3 · understanding

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

Question 6 · difficulty L3 · understanding

Following are the steps involved in the process of PCR. A. Annealing B. Amplification (~1 billion times) C. Denaturation D. Treatment with Taq polymerase and deoxynucleotides E. Extension Choose the correct sequence of steps of PCR from the options given below :

• A. $$\mathrm{C} \rightarrow \mathrm{A} \rightarrow \mathrm{D} \rightarrow \mathrm{E} \rightarrow \mathrm{B}$$
• B. $$\mathrm{A} \rightarrow \mathrm{B} \rightarrow \mathrm{E} \rightarrow \mathrm{D} \rightarrow \mathrm{C}$$
• C. $$\mathrm{A} \rightarrow \mathrm{C} \rightarrow \mathrm{E} \rightarrow \mathrm{D} \rightarrow \mathrm{B}$$
• D. $$\mathrm{D} \rightarrow \mathrm{B} \rightarrow \mathrm{E} \rightarrow \mathrm{C} \rightarrow \mathrm{A}$$

Question 7 · difficulty L3 · understanding

Thermostable DNA polymerase used in PCR was isolated from :

• A. Thermus aquaticus
• B. Escherichia coli
• C. Agrobacterium tumifaciens
• D. Bacillus thuringiensis

Question 8 · difficulty L3 · understanding

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Polymerase chain reaction is used in DNA amplification. Reason (R) : The ampicillin resistant gene is used as a selectable marker to check transformation. In the light of the above statements, choose the correct answer from the options given below :

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Question 9 · difficulty L3 · understanding

Match List-I with List-II . List-I List-II (a) Protpolast fusion (i) Totipotency (b) Plant tissue culture (ii) Pomato (c) Meristem culture (iii) Somaclones (d) Micropropagation (iv) Virus free plants Choose the correct answer from the options given below.

• A. (a) (b) (c) (d) (iv) (iii) (ii) (i)
• B. (a) (b) (c) (d) (iii) (iv) (ii) (i)
• C. (a) (b) (c) (d) (ii) (i) (iv) (iii)
• D. (a) (b) (c) (d) (iii) (iv) (i) (ii)

Question 10 · difficulty L3 · understanding

Which of the following is not an application of PCR (Polymerase Chain Reaction)?

• A. Detection of gene mutation
• B. Molecular diagnosis
• C. Gene amplification
• D. Purification of isolated protein