- biology any of a class of red or blue-green pigments found in the red algae and cyanobacteria
- Any of a class of water-soluble, mostly red, orange, and blue pigments found in cyanobacteria and red algae. Phycobilins absorb the blue and blue-green frequencies of light which penetrate deep water, and allow red algae to carry on photosynthesis at greater depths than other organisms. Phycobilins are chemically similar to chlorophyll and, like the heme in hemoglobin, are often found bound to proteins.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.