Protoplasm

Protoplasm is the living content of a cell that is surrounded by a plasma membrane. It is a general term for the combination of the cytoplasm and nucleoplasm. In the 19th century, some scientists proposed that all life was built out of a fundamental unit of protoplasm, to which the current cell theory can be seen as a development.

History

The term "protoplasm" comes from the Greek "protos" for first, and "plasma" for thing formed. It was first used in 1846 by Hugo von Mohl to describe the "tough, slimy, granular, semi-fluid" substance within plant cells, to distinguish this from the cell wall and cell nucleus. The term was later applied to the contents of animal cells.

Composition

Protoplasm is composed of a mixture of small molecules such as ions, amino acids, monosaccharides and water, and macromolecules such as nucleic acids, proteins, lipids and polysaccharides. In eukaryotes, this is divided into the cytoplasm and nucleoplasm. In prokaryotes, due to the lack of a nucleus, all the protoplasm is cytoplasm.

Functions

Protoplasm is the site of all the complex biochemical reactions that maintain life. This includes the synthesis of complex molecules, the generation of energy, and the replication of genetic material.

See also

• Cell (biology)
• Cytoplasm
• Nucleoplasm