Question

Which one is the precursor of chlorophyll?
a. Tryptophan
b. Protochlorophyll
c. Bacteriochlorophyll
d. Bacterioviridin

Answer 1

Hint: Chlorophyll is a dominant pigment found in green plants and several algal species. It is responsible for trapping light energy from the sun that is used in photosynthesis. This pigment originates from some other pigment which gets converted to chlorophyll by the action of sunlight.

Complete answer:
When the seed starts to germinate it lacks chlorophyll because they are present in the dark and have protochlorophyll, once leaves appear and are exposed to sunlight, the protochlorophyll present in the leaves converts to chlorophyll. 5 aminolevulinate is also required for the conversion of protochlorophyll into chlorophyll.

Hence, the correct answer is option (B).

Additional information:
• Chlorophyll are magnesium porphyrin compounds consisting of four pyrrole rings called tetrapyrrole.
• Chlorophyll is present inside the chloroplasts which are found in the mesophyll layers of leaf which have thylakoids inside which is chlorophyll.
• Chloroplasts are known as ‘food factories’ of the plants as they carry out photosynthesis and generate food and energy for the plant.
• Four major types of chlorophyll are found – chlorophyll a, chlorophyll b, chlorophyll c and chlorophyll d, chlorophyll e, chlorophyll f.
• Protochlorophyll is found in association with pheo porphyrin in very small amounts. It is found in large amounts in yellow parts of pumpkin.
• Because of the presence of phytol chlorophyll is hydrophobic.

Note: Chlorophyll a and b are mostly found in the plants and other photosynthetic organisms. Chlorophyll c is a brownish-golden coloured pigment which is found along chlorophyll a. Bacteriochlorophyll and bacterioviridin are found in photosynthetic bacteria.