Question

Why is it important to include both the uncut PCR product and a standard on the gel for analysis?

A. To check for contamination

B. To determine the size of DNA fragments

C. To ensure proper PCR amplification

D. To assess the efficiency of the gel electrophoresis

Answer 1

The presence of both the uncut PCR product and a standard, like a DNA ladder, on a gel during electrophoresis allows for the determination of the size of DNA fragments. It serves as both a size reference and an indirect check for successful PCR amplification and gel efficiency.

Step-by-step explanation:

The importance of including both the uncut PCR product and a standard on the gel for analysis primarily helps B. To determine the size of DNA fragments.

When running an agarose gel electrophoresis, the presence of a DNA ladder, or molecular weight standard, allows you to estimate the sizes of the PCR fragments by comparing them against the known sizes of the DNA ladder fragments. Without the standard, it would be challenging to assess the length of your PCR products accurately. Additionally, ensuring that the uncut PCR product is the expected size can help confirm that the PCR amplification was successful, which indirectly contributes to verifying that contamination did not occur and the efficiency of the electrophoresis process.