Question

Which of the following pigments are found in brown algae?
A. Chl a, Chl c
B. Chl a, Chl d
C. Chl a, Chl c and fucoxanthin
D. Chl a, phycoerythrin

Answer 1

The members of Phaeophyceae also known as brown algae possess chlorophyll a, along with chlorophyll c, as well as carotenoids and xanthophyll. They vary in their colour which depend upon the amount of the xanthophyll pigment, as well as fucoxanthin present in them.

Complete answer:
Option A- Chlorophyll a, is a type of chlorophyll which is considered as most common and predominant in all oxygen-evolving photosynthetic organisms like higher plants, red as well as green algae. It is best at absorbing wavelengths in the 400-450 nm along with 650-700 nm of the electro-magnetic spectrum. Its molecular formula is written as ${C_{55}}{H_{72}}{O_5}{N_4}Mg$.
Chlorophyll c, is a type of chlorophyll that is present only in algae, specifically the diatoms, dinoflagellates as well as brown algae. Its main role is to pass on the light excitation to chlorophyll a. Its molecular formula is written as ${C_{35}}{H_{28}}{O_5}{N_4}Mg$.
Option – B – chlorophyll d, is a form of chlorophyll that occurs in marine red algae and cyanobacteria, as well as absorbs the infrared light of the electro-magnetic spectrum. It is the key chlorophyll in cyanobacteria living in an environment depleted in the visible light but abundant in infrared light. Its molecular formula is written as ${C_{54}}{H_{70}}{O_6}{N_4}Mg$.
Option – C – Fucoxanthin – Fucoxanthin is a xanthophyll that contributes more than 10 percent of the estimated total production of carotenoids in nature. It is considered an accessory pigment present in the chloroplasts of many brown macroalgae, like Fucus spp.
Option – D - Phycoerythrin is a red protein-pigment that is complex from the light-harvesting phycobiliprotein family, found in red algae as well as cryptophytes, accessory to the key chlorophyll pigments responsible for photosynthesis.

Thus, the right answer to the question is option- C “Chl a, Chl c, and Fucoxanthin”.

Note: The brown algae are characterized by five chief distinguishing features. The photosynthetic pigments consist of chlorophyll-a and chlorophyll-c, $\beta$ carotene, fucoxanthin, violaxanthin, diatoxanthin along with other xanthophylls.