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In its broadest sense, intracellular digestion is the breakdown of substances within the cytoplasm of a cell. For example, following phagocytosis, the ingested particle (or phagosome) fuses with a lysosome containing hydrolytic enzymes to form a phagolysosome; the pathogens or food particles within the phagosome are then digested by the lysosome's enzymes. Intracellular digestion can also refer to the process in which animals that ''lack'' a digestive tract bring food items into the cell for the purposes of digestion for nutritional needs. This kind of intracellular digestion occurs in many unicellular protozoans, in Pycnogonida, in some molluscs, Cnidaria and Porifera. There is another type of digestion, called extracellular digestion. In amphioxus, digestion is both extracellular and intracellular.〔http://www.biocyclopedia.com/index/general_zoology/subphylum_cephalochordata.php〕 ==Occurrence== Most organisms that use intracellular digestion belong to Kingdom Protista, such as amoeba and paramecium. Amoeba Amoeba uses pseudopodia to capture food for nutrition in a process called phagocytosis. Paramoecium Paramoecium uses cilia in the oral groove to bring food into the mouth pore which goes to the gullet. At the end of the gullet, a food vacuole forms. Undigested food is carried to the anal pore. Euglena Euglena is photosynthetic but also engulfs and digests microorganisms. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「intracellular digestion」の詳細全文を読む スポンサード リンク
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