Definition, structure and function of Lysosome
Definition, structure and function of Lysosome
Lysosomes
A simple description of lysosomes is that they are tiny sacs filled with fluid containing enzymes which enable the cell to process its nutrients and are also responsible for destroying the cell after it has died.
A lysosome is a type of membrane-bound organelle that is present in animal cells. Lysosomes have a single outer membrane consisting of a phospholipid bilayer and contain acid hydrolases which are enzymes capable of breaking-down macromolecules.
Structure of Lysosomes - The outer surface is formed by a single membrane, a phospholipid bilayer that can fuse with some other membrane-bound organelles.
- Approx. spherical shape of diameter ranging up to one micrometre (1 μm).
- A single lysosome contains many enzyme molecules.
- The enzymes contained within lysosomes are known collectively as acid hydrolases and work best at in acidic environments, i.e. at low pH. The interior of lysosomes is acidic (about pH 4.8 to 5) compared with the slightly basic (about pH 7.2) intracellular fluid, which is also called cytosol, that surrounds organelles such as lysosomes within cells.
Functions of Lysosomes The functions of lysosomes concern the different ways in which the enzymes contained within the membrane (that defines and encloses the lysosome) affect other materials, which can originate from either outside or inside the cell.
- Release enzymes outside of the cell (exocytosis)
which may serve the purpose of destroying materials around the cell. - Break-down 'digestion' of materials from inside the cell (autophagy)
- Break-down 'digestion' of materials from outside the cell (heterophagy)
- Recycle the products of biochemical reactions that have taken place following materials being brought into the cell by endocytosis.
In general, the functions of lysosomes involve breaking-down i.e. processing to 'make safe' or make use of, or removing from the cell e.g. by exocytosis, useless and potentially harmful materials such as old worn-out parts of the cell or potential threats such bacteria.
Lysosomes
A simple description of lysosomes is that they are tiny sacs filled with fluid containing enzymes which enable the cell to process its nutrients and are also responsible for destroying the cell after it has died.
A lysosome is a type of membrane-bound organelle that is present in animal cells. Lysosomes have a single outer membrane consisting of a phospholipid bilayer and contain acid hydrolases which are enzymes capable of breaking-down macromolecules.
- The outer surface is formed by a single membrane, a phospholipid bilayer that can fuse with some other membrane-bound organelles.
- Approx. spherical shape of diameter ranging up to one micrometre (1 μm).
- A single lysosome contains many enzyme molecules.
- The enzymes contained within lysosomes are known collectively as acid hydrolases and work best at in acidic environments, i.e. at low pH. The interior of lysosomes is acidic (about pH 4.8 to 5) compared with the slightly basic (about pH 7.2) intracellular fluid, which is also called cytosol, that surrounds organelles such as lysosomes within cells.
The functions of lysosomes concern the different ways in which the enzymes contained within the membrane (that defines and encloses the lysosome) affect other materials, which can originate from either outside or inside the cell.
- Release enzymes outside of the cell (exocytosis)
which may serve the purpose of destroying materials around the cell. - Break-down 'digestion' of materials from inside the cell (autophagy)
- Break-down 'digestion' of materials from outside the cell (heterophagy)
- Recycle the products of biochemical reactions that have taken place following materials being brought into the cell by endocytosis.
In general, the functions of lysosomes involve breaking-down i.e. processing to 'make safe' or make use of, or removing from the cell e.g. by exocytosis, useless and potentially harmful materials such as old worn-out parts of the cell or potential threats such bacteria.
