Question

Photosynthetic pigments of the Rhodophyceae (Red algae) are:
A. Chlorophyll ‘a’ and ‘b’
B. Chlorophyll ‘a’ and ‘c’, fucoxanthin
C. Chlorophyll ‘a’ and ‘d’
D. Chlorophyll ‘a’ and ‘d’ and phycoerythrin

Answer 1

Hint: Red algae have red colour due to presence of phycoerythrin pigment. Red algae belong to the genus Porphyra and contain porphyran and they contain sulphated polysaccharides in the amorphous sections of their cell walls.

Complete answer:
Red algae or rhodophyta is the oldest group of the eukaryotic algae. It is mostly multicellular and marine algae that is, it is present in the water. It has a double cell wall and outer surface contains polysaccharides of agarose and agaropectin. So, this is also a good source of agar.
It contains chloroplast which helps in gaining specific colour to it. These pigments are water soluble and contain evenly spaced and ungrouped thylakoids. Other pigments which present in it are chlorophyll ‘a’, alpha- and beta- carotene (precursor of vitamin A), lutein and others. In these chloroplasts, grana are absent and phycobilisomes are attached on the stromal surface of the thylakoid membrane.
Thus, we can conclude that red algae contain photosynthetic pigments which are Chlorophyll ‘a’, ‘d’ and phycoerythrin is the pigment which is responsible for the colour of the red algae.

Thus, the correct option is option ’D’ that is, Chlorophyll ‘a’ and ‘d’ and phycoerythrin. 

Note: Reproduction of the algae is dependent on factors like length of the day. Red algae can reproduce sexually and asexual. Asexual reproduction can take place through fragmentation, propagules production or by cell division.