Free PCR Thermal Cycling Parameters & Optimization Questions and Answers

Question 1

What is the typical temperature for the denaturation step in PCR?

Accepted Answer

94–95°C

Answer

70–72°C

Answer

40–50°C

Answer

20–25°C

Question 2

What temperature range is used for primer annealing?

Accepted Answer

50–65°C

Answer

30°C

Answer

75°C

Answer

90°C

Question 3

Why is the elongation step performed at 72°C?

Accepted Answer

It is the optimal temperature for Taq polymerase

Answer

To cool primers

Answer

To break DNA

Answer

It removes RNA

Question 4

What can happen if annealing temperature is too low?

Accepted Answer

Non-specific products form

Answer

Enzyme inactivation

Answer

Template degrades

Answer

Cycle time increases

Question 5

Which parameter affects specificity of PCR the most?

Accepted Answer

Annealing temperature

Answer

Elongation time

Answer

Initial denaturation

Answer

Final extension

Question 6

Why is cycle number important in PCR?

Accepted Answer

It controls DNA yield and fidelity

Answer

It defines RNA yield

Answer

It sets probe sequence

Answer

It affects pH

Question 7

What is the purpose of a final extension step?

Accepted Answer

Complete any unfinished strands

Answer

Cool the PCR tube

Answer

Begin denaturation

Answer

Store the DNA

Question 8

How can optimization improve PCR efficiency?

Accepted Answer

Enhances product quality and consistency

Answer

Shortens primers

Answer

Lowers enzyme use

Answer

Reduces denaturation

Question 9

Which element helps avoid non-specific amplification?

Accepted Answer

Hot-start polymerase

Answer

Cool-start primers

Answer

Low MgCl₂

Answer

High cycle count