A M S ARUN KRISHNA
Last Activity: 9 Years ago
ENDOCYTOSIS
Endocytosis and exocytosis are active processes involving bulk transport materials through membranes, either into cells (endocytosis) or out of cells (exocytosis). Amoeba engulfs food through this endocytosis process.
Endocytosis occurs by an in folding or extension of the plasma membranes to form a vesicle or vacuole. It is of two types
PHAGOCYTOSIS
Intake of substances as solid particles is called phagocytosis. Membrane folds out going round the particle, forming a cavity thus engulfing the whole particle. Cells involved in this process are called phagocytes and said to be phagocytic. Example : Some white blood cells. A phagocytic vacuole is formed during uptake.
PINOCYTOSIS
Intake of substances as fluid droplets or in liquid form is called pinocytosis. Membrane folds in and forms a cup like structure sucks in the droplets. Vesicles which are very small are formed during intake.
Pinocytosis is often associated with amoeboid protozoans, and in kidney cells involved in fluid exchange. It can also occur in plant cells