Question

Rhodophyceae is red coloured due to
A) Xanthophyll
B) Carotenoids
C) Phycoerythrin
D) Phycocyanin

Answer 1

Hint: Red Algae or Rhodophyceae is a distinctive type of species that are mostly found in the freshwater lakes and are the oldest type of eukaryotic algae.

Complete answer:
 Let us analyze each option to find out the correct answer.
Option A: Xanthophyll is found in all young leaves and in etiolated leaves. They are yellow pigments that occur widely in nature and form one of two major divisions of the carotenoid group; the other division is formed by the carotenes. Therefore, this is an incorrect option.
Option B: Carotenoids pigments are found in plants, algae, and photosynthetic bacteria. These pigments produce bright yellow, red, and orange colors in plants, vegetables, and fruits. Carotenoids act as a type of antioxidant for humans. Therefore, this is an incorrect option.
Option C: Rhodophyta (red algae) has a predominance of the red pigment, phycoerythrin along with chlorophyll a and chlorophyll d. The red algae usually reproduce vegetatively by fragmentation, asexually by non-motile spores, and sexually by non-motile gametes. The common members are Polysiphonia, Porphyra, Gracilaria, and Gelidium. Therefore, this is the correct option.
Option D: Phycocyanin is a light-harvesting, pigment-binding protein isolated from algae. It is a non-toxic, water-soluble pigment-protein from microalgae that exhibits antioxidant, anti-inflammatory, Therefore, this is an incorrect option.

Thus, the correct answer is option (C) Phycoerythrin.

Note:It should be noted that the agar or agar-agar, a jelly-like substance that is used in puddings, dairy toppings, and other instant food products is extracted from Red algae.