Large particles and bacteria can be engulfed by phagocytosis.Phagocytes move in a particular direction down a chemical gradient. This is called chemotaxis and is caused by a chemoattractant being released in one location.Phagocytes can recognise chemicals on the surface of bacteria such as bacterial lipopolysaccharides which are the major outer surface membrane components present in almost all Gram-negative bacteria.The phagocyte engulfs the pathogen in a vesicle called the phagosome. Lysosomes from inside the cell move towards the phagosome and fuse with it.Lysozyme within the phago-lysosome digest and destroy the pathogen by hydrolysis.The soluble products are absorbed into the cytoplasm of the phagocyte.