Silva, Paul C. Department of Botany, University of California, Berkeley, California.
Moe, Richard L. Department of Botany, University of California, Berkeley, California.
A division of the plant kingdom (also known as Chromophyta) comprising nine classes of algae: Bacillariophyceae (diatoms), Chrysophyceae (golden or golden-brown algae), Cryptophyceae, Dinophyceae (dinoflagellates), Eustigmatophyceae, Phaeophyceae (brown algae), Prymnesiophyceae, Raphidophyceae, and Xanthophyceae (yellow-green algae). Some of these classes are closely related, while others stand so far apart that they are sometimes assigned to their own divisions. The chief unifying character is the presence of chlorophyll c rather than chlorophyll b as a complement to chlorophyll a (although only chlorophyll a is present in Eustigmatophyceae). The chloroplasts are usually brown or yellowish because of large amounts of β-carotene and various xanthophylls, many of which are restricted to one or more classes. Storage products include lipids, starch, and glucans (glucose polymers with β-1,3 linkages). In all classes except Dinophyceae, the chloroplast is surrounded by chloroplast endoplasmic reticulum that is continuous with the nuclear envelope, and the deoxyribonucleic acid of the chloroplast forms an annular genophore. Except in Cryptophyceae, thylakoids are in groups of three. In most classes, motile cells bear two unequal flagella, one of which may be almost completely reduced and at least one of which bears two rows of hairlike appendages. Algae in this division range in size and complexity from unicellular flagellates to gigantic kelps. See also: Algae; Bacillariophyceae; Chrysophyceae; Cryptophyceae; Dinophyceae; Eustigmatophyceae; Phaeophyceae; Prymnesiophyceae; Raphidophyceae; Xanthophyceae
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information