The easiest way to identify the DNA two different tubes where one has high G-C content.
(a) A sucrose density gradient
(b)Agarose gel electrophoresis
(c) A cesium chloride density gradient
(d) All of the above

The correct answer is:

(c) A cesium chloride density gradient

Explanation:

• DNA with a higher G-C content has a higher density than DNA with a lower G-C content because G-C base pairs have three hydrogen bonds, making them more stable and compact compared to A-T base pairs (which have only two hydrogen bonds).
• Cesium chloride (CsCl) density gradient centrifugation separates DNA based on its buoyant density, making it the best method to distinguish between DNA samples with different G-C contents.
• Sucrose density gradients (option a) separate molecules based on size and shape, not density, making them ineffective for this purpose.
• Agarose gel electrophoresis (option b) primarily separates DNA based on size, not density differences due to G-C content.
• Option (d) “All of the above” is incorrect because not all methods listed are effective for distinguishing DNA based on G-C content.

Thus, CsCl density gradient centrifugation is the easiest and most effective method to identify DNA with different G-C content.