Question

Phycobilin occur in
A. Blue green algae
B. Red algae
C. Green algae
D. Both a and b

Answer 1

hint: Phycobilins or biliproteins are light-capturing pigments in some algae. They act as accessory photosynthetic pigments and are able to absorb light in green and orange spectral regions where chlorophyll absorbs poorly.

Complete step by step answer:
There are Three classes of pigments in cells of algae, Chlorophyll(a,b,c,d, and e), carotenoids(alpha, beta, gamma carotene, lycopene, flavine, fucoxanthin, violaxanthin, myxoxanthin, zeaxanthin), and phycobilins or biliproteins(phycocyanin, phycoerythrin, allophycocyanin). Rhodophyceae includes the red algae which are characterized by distinctive red coloration. The thallus of red algae is red colored due to the presence of excessive amounts of the pigments phycoerythrin and phycocyanin. Cyanobacteria or blue- green algae are prokaryotic organisms. They are considered as monerans. The chief pigments in cyanobacteria are chlorophyll- a, phycocyanin, allophycocyanin, phycoerythrin, myxoxanthin, Oscillaxanthin, β- carotene, and lutein, etc. The presence of Phycocyanin(blue) and phycoerythrin(red) gives them a characteristic blue- green color.

Additional information:
- Algae are simple,chlorophyll- bearing, and photosynthetic non- vascular plants.
- Their body is a simple thallus without differentiation into roots, stems, and leaves.
- The chief pigments in them are chlorophyll, carotenoids, and phycobilins, or biliproteins.
- The three different phycobilins are Phycocyanin, phycoerythrin, and allophycocyanin.
- Phycocyanin is a blue accessory pigment used to trap light for photosynthesis.
- Phycoerythrin is a red protein pigment used for light trapping
- Allophycocyanin is an intensely bright phycobiliprotein.
- The presence of phycocyanin and phycoerythrin in cyanobacteria and red algae gives them characteristic colors.
- Phycoerythrin is significant in that it can absorb the light energy of short wavelengths more effectively than chlorophylls can.
So, the correct answer is ‘both a and b, blue- green algae and red algae’.

Note:
- The name Cyanophyceae or blue- green algae denotes the presence of blue- green pigment phycocyanin.
- Phycobilin allows red algae to carry out photosynthesis in deep water.
- Phycocyanin is used in medicine and food applications. Red algae are the most beautifully colored members of sea- weeds.