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Biology

Key Terms

BiologyKey Terms

Key Terms

biological carbon pump
process by which inorganic carbon is fixed by photosynthetic species that then die and fall to the sea floor where they cannot be reached by saprobes and their carbon dioxide consumption cannot be returned to the atmosphere
bioluminescence
generation and emission of light by an organism, as in dinoflagellates
contractile vacuole
vesicle that fills with water (as it enters the cell by osmosis) and then contracts to squeeze water from the cell; an osmoregulatory vesicle
cytoplasmic streaming
movement of cytoplasm into an extended pseudopod such that the entire cell is transported to the site of the pseudopod
endosymbiosis
engulfment of one cell within another such that the engulfed cell survives, and both cells benefit; the process responsible for the evolution of mitochondria and chloroplasts in eukaryotes
endosymbiotic theory
theory that states that eukaryotes may have been a product of one cell engulfing another, one living within another, and evolving over time until the separate cells were no longer recognizable as such
hydrogenosome
organelle carried by parabasalids (Excavata) that functions anaerobically and outputs hydrogen gas as a byproduct; likely evolved from mitochondria
kinetoplast
mass of DNA carried within the single, oversized mitochondrion, characteristic of kinetoplastids (phylum: Euglenozoa)
mitosome
nonfunctional organelle carried in the cells of diplomonads (Excavata) that likely evolved from a mitochondrion
mixotroph
organism that can obtain nutrition by autotrophic or heterotrophic means, usually facultatively
pellicle
outer cell covering composed of interlocking protein strips that function like a flexible coat of armor, preventing cells from being torn or pierced without compromising their range of motion
phagolysosome
cellular body formed by the union of a phagosome containing the ingested particle with a lysosome that contains hydrolytic enzymes
plankton
diverse group of mostly microscopic organisms that drift in marine and freshwater systems and serve as a food source for larger aquatic organisms
plastid
one of a group of related organelles in plant cells that are involved in the storage of starches, fats, proteins, and pigments
raphe
slit in the silica shell of diatoms through which the protist secretes a stream of mucopolysaccharides for locomotion and attachment to substrates
test
porous shell of a foram that is built from various organic materials and typically hardened with calcium carbonate
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