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The chloroplasts of red algae have chlorophylls a and c (often), and phycobilins, while those of green algae have chloroplasts with chlorophyll a and b without phycobilins. Land plants are pigmented similarly to green algae and probably developed from them, thus the Chlorophyta is a sister taxon to the plants; sometimes the Chlorophyta, the ...
Green algae have chloroplasts that contain chlorophyll a and b, giving them a bright green colour, as well as the accessory pigments beta carotene (red-orange) and xanthophylls (yellow) in stacked thylakoids. [12] [13] The cell walls of green algae usually contain cellulose, and they store carbohydrate in the form of starch. [14]
The oldest undisputed evidence of cyanobacteria is dated to be 2.1 Ga ago, but there is some evidence for them as far back as 2.7 Ga ago. [27] Cyanobacteria might have also emerged 3.5 Ga ago. [173] Oxygen concentrations in the atmosphere remained around or below 0.001% of today's level until 2.4 Ga ago (the Great Oxygenation Event). [174]
Other forms of chlorophyll exist, such as the accessory pigments chlorophyll b, chlorophyll c, chlorophyll d, [12] and chlorophyll f. Chlorophyll b is an olive green pigment found only in the chloroplasts of plants , green algae , any secondary chloroplasts obtained through the secondary endosymbiosis of a green alga, and a few cyanobacteria ...
The Chlorophyceae are one of the classes of green algae, distinguished mainly on the basis of ultrastructural morphology. [2] They are usually green due to the dominance of pigments chlorophyll a and chlorophyll b. The chloroplast may be discoid, plate-like, reticulate, cup-shaped, spiral- or ribbon-shaped in different species.
[note 1] Unlike red and green algae, glaucophytes have never been involved in secondary endosymbiosis events. [10] The cells of the Archaeplastida typically lack centrioles and have mitochondria with flat cristae. They usually have a cell wall that contains cellulose, and food is stored in the form of starch. However, these characteristics are ...
Some Phaeophyceae (brown algae, seaweeds) develop as large multicellular thalli with differentiated tissues. [7] All ochrophytes uniformly have tubular mitochondrial cristae . [ 10 ] This is a common trait shared with their relatives, heterotrophic stramenopiles , as well as other closely related groups such as Rhizaria , Telonemia and Alveolata .
The chlorophyte and charophyte green algae and the embryophytes or land plants form a clade called the green plants or Viridiplantae, that is united among other things by the absence of phycobilins, the presence of chlorophyll a and chlorophyll b, cellulose in the cell wall and the use of starch, stored in the plastids, as a storage polysaccharide.