Question

The DNA fragments separated on an agarose gel can be visualised after staining with

• A. Bromophenol blue
• B. Acetocarmine
• C. Aniline blue
• D. Ethidium bromide

Answer 1

The correct option is D

Ethidium bromide

The correct option is D.

Explanation of the correct option:

Ethidium bromide:

1. The small DNA fragments when stained with ethidium bromide they can be visualised under UV light easily.
2. It is one of the most commonly used stains for detecting DNA or RNA fragments.
3. It absorbs UV radiation of wavelength 300 nm to 360 nm.
4. It stains the DNA fragment dark red in colour.

Explanation of the incorrect options:

Option A:

Bhromophenol blue is a laboratory indicator which changes colour from yellow at PH 3 to purple at PH 4.6.

Option B:

1. Acetocarmine is a saturated solution which is used for staining fresh and non-fixed chromosomes.
2. It contains 45% acetic acid.

Option C:

1. Aniline blue is popularly known as China blue it is basically a soluble dye used as a biological dye in the field of fluorescence microscopy.
2. It is used for staining collagen fibres.

Final answer: The DNA fragments separated on an agarose gel can be visualised after staining with ethidium bromide.