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The glycocalyx is a type of identifier that the body uses to distinguish between its own healthy cells and transplanted tissues, diseased cells, or invading organisms. Included in the glycocalyx are cell-adhesion molecules that enable cells to adhere to each other and guide the movement of cells during embryonic development. [3]
The branching system of Chara species is complex with branches derived from apical cells which cut off segments at the base to form nodal and internodal cells alternately. [4] The main axes bear whorls of branches in a superficial resemblance to Equisetum (a vascular plant). [ 5 ]
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 ...
The algae supply nutrients produced via photosynthesis to the Hydra. Because the algae live in the vacuoles of the cells, they are protected from the digestive enzymes of the Hydra. [3] During long period of darkness, such as storms or blooms that block sunlight, algae loss starts from the tentacles, hypostome and growth region.
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]
Algae constitute a polyphyletic group since they do not include a common ancestor, and although their chlorophyll-bearing plastids seem to have a single origin (from symbiogenesis with cyanobacteria), they were acquired in different ways. Green algae are a prominent examples of algae that have primary chloroplasts derived from endosymbiont ...
Brown algae have a δ 13 C value in the range of −30.0‰ to −10.5‰, in contrast with red algae and greens. This reflects their different metabolic pathways. [51] They have cellulose walls with alginic acid and also contain the polysaccharide fucoidan in the amorphous sections of their cell walls.
The microbial cells growing in a biofilm are physiologically distinct from planktonic cells of the same organism, which, by contrast, are single cells that may float or swim in a liquid medium. [8] Biofilms can form on the teeth of most animals as dental plaque , where they may cause tooth decay and gum disease .