Free PCR Data Analysis & Troubleshooting Questions and Answers

Question 1

What does a clear single band on a gel indicate after PCR?

Accepted Answer

Successful target amplification

Answer

Multiple template presence

Answer

Contamination

Answer

No amplification

Question 2

What might cause no bands to appear in a PCR gel?

Accepted Answer

Missing enzyme or wrong temperature

Answer

Too many cycles

Answer

Overstaining

Answer

Extra primers

Question 3

What does a smear on the gel indicate?

Accepted Answer

Degraded DNA or over-cycling

Answer

High specificity

Answer

Strong amplification

Answer

Low annealing temp

Question 4

Which factor helps confirm primer specificity?

Accepted Answer

Melt curve analysis

Answer

Cycle number

Answer

Final extension

Answer

Enzyme type

Question 5

Why is a negative control used in PCR?

Accepted Answer

To check for contamination

Answer

To boost yield

Answer

To stain DNA

Answer

To reduce heat

Question 6

What is a common cause of non-specific bands?

Accepted Answer

Low primer specificity or annealing temp

Answer

Perfect buffer

Answer

Too few cycles

Answer

Extra Taq

Question 7

What does high background noise on a gel suggest?

Accepted Answer

Primer dimers or contamination

Answer

Strong target DNA

Answer

Slow migration

Answer

High DNA quality

Question 8

How can yield be increased if amplification is weak?

Accepted Answer

Adjust template or cycling conditions

Answer

Reduce enzyme

Answer

Skip denaturation

Answer

Use less primer

Question 9

What is an internal control in PCR?

Accepted Answer

A known DNA sequence to check reaction success

Answer

An off-target primer

Answer

A temperature marker

Answer

A failed sample