Question

Name the pigment which imparts red colour to red algae
A. Phycoerythrin
B. Phycocyanin
C. Carotene
D. Both A and B

Answer 1

Hint: Red algae, or Rhodophyta, is one of the oldest groups of eukaryotic algae. The Rhodophyta also contains one among the biggest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority of species (6,793) are discovered in the Florideophyceae (class), and more often than not consist of multicellular, marine algae, which include many great seaweeds. Red algae are abundant in marine habitats however are surprisingly uncommon in freshwaters.

Complete answer:
• Phycoerythrin (PE) pigment is a crimson protein-pigment complex from the light-harvesting phycobiliprotein family.
• It is found in red algae and cryptophytes, accessory to the main chlorophyll pigments responsible for photosynthesis in the plants.
• Like all phycobiliproteins, it's miles composed of a protein part covalently binding chromophores called phycobilins.
• In the phycoerythrin circle of relatives, the most acknowledged phycobilins are phycoerythrobilin, the standard phycoerythrin acceptor chromophore, and sometimes phycourobilin.
• Phycoerythrins are composed of monomers, generally organised in a disk-formed time or hexamer (2d one is the functional unit of the antenna rods). These ordinary complexes also incorporate a third type of subunit, the γ chain of the algae.
• Red algae or Rhodophyta – It is a one-of-a-kind form of species which can be commonly located in the freshwater lakes and are the oldest kind of eukaryotic algae.
• They are crimson in shade due to the presence of a pigment known as chlorophyll A, phycocyanin, and phycoerythrin.

Hence, the correct answer is option (D).

Note: Phycoerythrin is a light harvesting pigment belongs to phycobiliprotein, act as an accessory protein to the main chlorophyll pigment whereas phycocyanin absorbs and emits light at a longer wavelength and are usually found in cyanobacteria. It also belongs to the phycobiliproteins family used to reflect red light due to which algae look red.