Protoplasm is the living contents of a cell that is surrounded by a plasma membrane. It is a general term for the cytoplasm. 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 the protoplasm surrounding the cell nucleus is known as the cytoplasm and that inside the nucleus as the nucleoplasm. In prokaryotes the material inside the plasma membrane is the bacterial cytoplasm, while in Gram-negative bacteria the region outside the plasma membrane but inside the outer membrane is the periplasm.

The word "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, cell nucleus and the cell sap within the vacuole. Thomas Huxley later referred to it as the "physical basis of life" and considered that the property of life resulted from the distribution of molecules within this substance. Its composition, however, was mysterious and there was much controversy over what sort of substance it was. Attempts to investigate the origin of life through the creation of synthetic "protoplasm" in the laboratory were not successful, yet.

The idea that protoplasm of eukaryotes is divisible into a ground substance called "cytoplasm" and a structural body called the cell nucleus reflects the more primitive knowledge of cell structure that preceded the development of electron microscopy, when it seemed that cytoplasm was a homogeneous fluid and the existence of most sub-cellular compartments, or how cells maintain their shape, was unknown. Today, it is known that the cell contents are structurally very complex and contain multiple organelles.

Protoplasm can exist in two forms: 1. Sol state 2. Gel state, so called because its consistency resembles that of jelly.

Whether protoplasm is in the sol or the gel state depends on the physiological state of the cell.

Other articles related to "protoplasm":

Ergastic Substance
... Ergastic substances are non-protoplasm materials found in cells ... The living protoplasm of a cell is sometimes called the bioplasm and distinct from the ergastic substances of the cell ... Ergastic substances may appear in the protoplasm, in vacuoles, or in the cell wall ...
Bathybius Haeckelii
... Haeckel had theorized about Urschleim ("primordial slime"), a protoplasm from which all life had originated ... Huxley thought Bathybius could be that protoplasm, a missing link (in modern terms) between inorganic matter and organic life ... did not agree but speculated that Bathybius formed a continuous mat of living protoplasm that covered the whole ocean floor ...
Slime Mould - Life Cycle
... The streaming protoplasm within a plasmodial strand can reach speeds of up to 1.35 mm per second which is the fastest rate recorded for any micro-organism ... plasmodium is accomplished when more protoplasm streams to advancing areas and protoplasm is withdrawn from rear areas ...
Wanda Kirkbride Farr - Notable Scientific Discovery
... to this time to emerge fully formed in the cell's protoplasm ... could be seen to occur in stages, in structures called plasmids inside the cell protoplasm ... Farr discovered that cellulose-manufacturing plastids do exist in the protoplasm of the cell, but that such plastids had been invisible because they have a light refractive ...
Hugo Von Mohl
... The word protoplasm was his suggestion the nucleus had already been recognized by R ... Brown and others but Mohl showed in 1844 that the protoplasm is the source of those movements which at that time excited so much attention ... lining of the vacuolated cell, and first described the behaviour of the protoplasm in cell division ...