Like mitochondrial lysosomes are also typical membrane bound and dense fluid filled sac like cytoplasmic organelles of all eukaryotic cells these however, different from mitochondria in their smaller size 0.08to0.8 in diameter and typically spheroidal ellipsoidal or ovoid shape having a single limiting in units membrane and containing only hydrolytic enzymes in their watery ,matrix, These were first observed and isolated by Nobel laureate de duve 1949 and named , lysosomes by him and novikoff in 1955 .
These organelles arise as primary lysosomes from diastalcisterna at the maturing at the maturing face of Golgi complex units. Each primary lysosome is known to contain 40to50 hydrolytic enzyme in an acidic medium, the protein back bones of these enzyme are synthesize by ribosomes, accumulate and glycosylated conjugated to carbohydrates in endoplasmic reticulum and then transferred to Golgi complex through transitional vesicles in the cisternae of Golgi complex .these enzyme are sorted out and ultimately packaged into primary lysosomes.
Functions of lysosomes: Intracellular and extracellular digestion of most biological substance is the sole function of lysosomes These are -
1. Digest liquid or silid materials taken in by cells from extracellular medium respectively by pinocytosis and phagocytises .
2. Bring about breakdown of organic materials outside the cells when poured out in extracellular medium by the saprozoic organisms and
3. Digest worn out or unnecessary parts of the cells or even whole cells by the so called process of autophagy.