Question

“Chlorophyll a” is found in
A. All Oxygen releasing photosynthetic forms
B. Only higher plants
C. Higher plants that photosynthesise
D. All photosynthetic eukaryotes.

Answer 1

Hint: Chlorophyll is a pigment present in the leaves of plants and other autotrophs. It captures sunlight and along with carbon dioxide and water, it helps in the production of assimilates.

Complete answer: Chlorophyll is the green pigment that helps organisms to absorb sunlight during the process of photosynthesis. Chlorophyll is seen in many organisms other than plants. With the help of this pigment, organisms are able to prepare their own food. Hence, it is present in all oxygen releasing photosynthetic forms. Many types of chlorophyll are known. They are chlorophyll a, chlorophyll b, chlorophyll c and chlorophyll d. Among these, chlorophyll a is widely distributed in all autotrophic plants. The chlorophyll contains a porphyrin ring that has a magnesium atom at the centre. A long hydrocarbon chain is connected to it called a phytol tail. Photochemical reaction, which is also called light reaction, takes place only in organisms having chlorophyll a. Chlorophyll a molecules are of different types. Some of them are chlorophyll a 673, chlorophyll a 683, etc. Chlorophyll a is the chief pigment associated with photosynthesis. Oxygen release is associated with the photochemical phase of the light reaction. It involves two pigment systems in which chlorophyll a is the reaction centre of both systems. Oxygen is released in the process called non-cyclic photophosphorylation.
Hence the correct answer is option A.

Note: Autotrophs use sunlight, water, carbon dioxide, etc. in the process of photosynthesis.
All autotrophs are not photosynthetic in nature. Some produce food by a process called chemosynthesis. Here, they use chemical substances in order to prepare food. They are called chemoautotrophs. Examples are certain chemosynthetic bacteria like green sulphur bacteria, purple sulphur bacteria, etc.