PCR and the steps of recombinant DNA technology — practice questions

Question 1 · 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 2 · 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 3 · 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 4 · 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 5 · 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 6 · 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 7 · 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 8 · 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

Question 9 · difficulty L3 · understanding

Which of the following is a correct sequence of steps in a PCR (Polymerase Chain Reaction)?

• A. Annealing, Denaturation, Extension
• B. Denaturation, Annealing, Extension
• C. Denaturation, Extension, Annealing
• D. Extension, Denaturation, Annealing

Question 10 · difficulty L3 · understanding

During the process of gene amplification using PCR, if very high temperature is not maintained in the beginning, then which of the following steps of PCR will be affected first?

• A. Ligation
• B. Annealing
• C. Extension
• D. Denaturation