Protoplasm is the living material that is found in a cell. An older term for the living parts of a cell, protoplasm was first used in 1846 by Hugo von Mohl. Von Mohl used the term to describe what he called a slimy, grainy substance that was found in plant cells.
Protoplasm which makes up the fluid portion of the cell consists of the cell’s cytoplasm and its nucleus. It is mainly composed of nucleic acids, proteins, lipids, inorganic salts, water and carbohydrates.
Water: Water, which is composed of two hydrogen atoms and one oxygen atom, is necessary for the maintenance of life. In the cell, water is of utmost importance because the majority of chemical reactions take place in water.
Nucleic Acids: DNA and RNA are the most important examples of nucleic acids. Both DNA and RNA function in cells as a means of giving important instructions to the cell, as far as structure and function; for example functioning in cell growth and replication.
Proteins: Proteins which are made up of polymers of amino acids are found in the DNA molecule. In addition to the role they play with DNA, proteins are involved in just about every other cell function.
A certain type of protein, known as an enzyme, works within the cell to speed up necessary cell reactions, reactions which are crucial to cellular metabolism.
Lipids: Lipids are molecules which include sterols, fats, and some important vitamins. Lipids function in energy storage and are found within cell membranes. Lipids function is cell signaling, a method of communication between different parts of a cell.
Inorganic Salts: Inorganic salts, which are compounds, composed of sodium, potassium, chloride and calcium play vital roles in the cell. All of these compounds are essential to life and play an important role in reactions which take place in the cell.
Carbohydrates: A carbohydrate is an organic compound which is made up of carbon, oxygen and hydrogen. For every two atoms of hydrogen, there is one atom of oxygen found in carbohydrates.
Carbohydrates function in cells in energy storage and structure; lending themselves often to shape, lending their backbones to the structure of RNA. Carbohydrates also function in the process of biosynthesis in cells, a process where more complex compounds are made from simpler ones.
Proteins, known as enzymes are often involved in the biosynthesis process. Examples of these more complex compounds include such things as proteins and vitamins.