, bounded by a single membrane, that contains hydrolytic enzymes (e.g. acid phosphatase, ribonuclease, β-galactosidase, protease) capable of degrading cellular components. Phagolysosomes are formed in association with vacuoles containing ingested material (see endocytosis
). Autolysis occurs when components of the cell, e.g. mitochondria or fragments of endoplasmic reticulum, are degraded by the activity of lysosomal enzymes. This process is important in the recycling of valuable nutrients from ageing plant tissue. Vesicles from the *golgi apparatus
are also involved in the intracellular translocation of lysosomal enzymes.