Question

Photosynthetic pigments such as chl a chl b, xanthophyll, and carotene can be separated by which of the following techniques?
A) Paper chromatography
B) Gel electrophoresis
C) X- ray diffusion
D) ELISA test

Answer 1

Hint: It is an analytical method mainly used for the separation of colored chemicals or substances. Its main principle is mainly partition rather than adsorption and also used as a teaching tool. By this method, a complex mixture of compounds having a similar polarity is separated.

Complete answer:
- For the metabolic process all living organisms require energy. Sun is the ultimate source of energy.
- Plants, protists, blue-green algae are the photosynthetic organisms that convert light energy into chemical energy required for metabolism. During photosynthesis, molecules are required to capture the light energy.

- Molecules also known as pigments due to the wavelength of the color they reflect. These pigments can be easily separated and identified using a paper chromatography technique.
- The pigment is composed of two green pigments Chlorophylls and two yellow pigments called carotenoids and these are separated according to their solubilities.
- The chlorophyll pigment is dissolved in a solvent and a drop is placed on to chromatography paper. The solvent carrying the solutes is slowly moving up the paper. How further the solvent moves depend upon the solubility of the solvent.
- When a pigment of tea leaves a separated using a chromatography paper we can see that the color of leaves is not due to the single pigment but due to the presence of four pigments which are Chlorophyll b (yellow-green) , Xanthophylls (yellow) , and carotenoids (yellow-orange).

Additional information:
Gel electrophoresis - In this technique a DNA fragment is separated according to their size. At the end of a gel, the samples are loaded into the Wells. DNA is negatively charged molecules. Therefore, when an electric current is applied to migrate towards the positive electrode.
X- Ray Diffusion - The information on structures, phases, Orientation of crystal, other structural parameters like the size of grain, crystallinity strain, and crystal defects all are characterized by this technique.
ELISA - For detection and the measurement of the antibodies in the blood this test is used. It helps in determining if the antibodies related to certain infectious conditions or not.
So, the correct answer is, ”A) Paper chromatography”.

Note:
- For separation and identification of different plant pigment paper chromatography is a very useful technique.
- There are four types of pigments of green plants that can be separated using this technique. Four pigments are two green pigments called Chlorophyll and two yellow pigments called carotenoids.