phagotrophic

Phagotrophic describes feeding by phagocytosis, a process in which a cell engulfs solid particles such as bacteria, algae, or detritus. In phagotrophy, membrane extends around a particle to form a phagosome, which typically fuses with lysosomes to form a phagolysosome where ingested material is digested. Nutrients are then absorbed or transported for use by the cell. Phagotrophy is distinct from osmotrophy, in which nutrients are absorbed as dissolved substances across the cell membrane.

Mechanism and cellular basis are centered on the cytoskeleton, particularly actin, which drives membrane protrusions and engulfment. Phagocytosis can be initiated by recognition of prey through surface receptors, followed by enclosure and internalization. Some cells compartmentalize waste material into residual bodies after digestion. Phagotrophy is widespread among protists, including amoebae and some ciliates, and is also a key feeding mode for certain immune cells in animals, such as macrophages and neutrophils.

Ecological and biological significance is broad. Phagotrophs control microbial populations, influence nutrient cycling, and form an important link in food webs by converting ingested prey into cellular biomass. In multicellular organisms, phagocytosis is central to innate immunity and pathogen clearance. While many eukaryotes rely on phagotrophy, others use osmotrophy or phototrophy, or combinations thereof in mixotrophic strategies.

In summary, phagotrophic feeding centers on the ingestion and digestion of solid particles through phagocytosis, supporting diverse ecological roles and evolutionary adaptations across different lineages.