Question

Which of the following is not true about gel electrophoresis?

• A. Gel electrophoresis can be used to separate nucleic acids or proteins.
• B. Agarose and polyacrylamide are routinely used in gel electrophoresis.
• C. In gel electrophoresis of DNA, the digested DNA fragments move toward the negative electrode of the tank.
• D. In gel electrophoresis of DNA, ethidium bromide, a DNA binding dye, is used to locate the DNA fragments of interest under UV light.

Hint:

Remember that DNA is a nucleic \textbf{acid}. Acids donate protons, leaving a negative charge. In electrophoresis, opposites attract, so negative DNA migrates to the positive pole (anode).

Answer 1

The Correct Option is C

Step 1: Concept Overview:
Gel electrophoresis separates molecules based on charge within an electric field. Migration direction is determined by the molecule's net charge. DNA possesses a negative charge due to its phosphate backbone.
Step 2: Statement Analysis:
Analyzing each statement:


(A) Correct. Gel electrophoresis is a widely applicable technique for separating nucleic acids (DNA and RNA) and proteins (commonly via SDS-PAGE).

(B) Correct. Agarose gels are suited for larger DNA fragments, while polyacrylamide gels (PAGE) provide higher resolution for smaller DNA fragments and proteins.

(C) Incorrect. DNA, being negatively charged, migrates towards the positive electrode (anode) under an electric field. Opposite charges attract.

(D) Correct. Ethidium bromide intercalates into DNA and emits fluorescence under UV light, enabling visualization of DNA bands.

Step 3: Conclusion:
The false statement is (C).