Question

Gel electrophoresis is used for

• A. Cutting of DNA into fragments
• B. Construction of recombinant DNA by joining with cloning vectors
• C. Isolation of DNA molecule
• D. Separation of DNA fragments according to their size

Answer 1

The Correct Option is D

Yes, gel electrophoresis is used for the separation of DNA fragments according to their size.

How it Works:

DNA samples are loaded into wells in an agarose gel and subjected to an electric field.

Since DNA is negatively charged due to its phosphate backbone, it moves towards the positive electrode (anode).

Smaller DNA fragments migrate faster and farther, while larger fragments move slower and remain near the wells.

DNA bands are visualized using staining agents like ethidium bromide (EtBr) or SYBR Green under UV light.

Applications:

DNA fingerprinting

PCR product analysis

Checking restriction enzyme digestion

DNA sequencing

Genetic disorder diagnosis

Thus, gel electrophoresis is a key technique for DNA fragment separation based on size.

Answer 2

Gel electrophoresis is a widely used technique in molecular biology that allows the separation and analysis of DNA, RNA, and proteins based on their size and charge.

In the case of DNA, the technique involves placing the DNA samples onto a gel matrix, typically made of agarose or polyacrylamide, and applying an electric field across the gel.

The DNA fragments migrate through the gel based on their size and charge, with smaller fragments moving faster and traveling farther from the point of origin.