Cytoplasm is the clear liquid that fills the cells of both plants and animals. It contains three parts, the cytosol, the organelles and cytoplasmic inclusions. This liquid functions to suspend and hold into place the organelles within the cell. It is within in this substance that many of the most basic, and most important, facets of biology take place.
The most basic part of cytoplasm is the the cytosol. The cytosol is the basic liquid part of the cell that does not contain any of the organelles or major chemical deposits. It usually is clear, and it takes up most of the space of the cell.
All of the parts of the cell, with the exception of the nucleus, are held within the cytoplasm. These parts are called organelles. The organelles are microscopic semi-organs that facilitate a number of important metabolic reactions, such as breaking down protein, producing energy and cell mitosis or meiosis. Examples of such organelles are Golgi bodies, mitochondria, endoplasmic reticulum and ribosomes. Without the function of these organelles, cells would wither and die, and life would not be possible.
Maintaining the shape of the cell and suspension of organelles is the most important task of cell cytoplasm, but it also serves in several other roles. Cytoplasm acts as a storage space for the chemical building blocks of the body, storing protein, oxygen and other substances until they can be used by the organelles, and storing the waste byproducts of metabolic reactions, such as carbon, until they can be disposed of. These stores are the cytoplasmic inclusions.
The last function that cytoplasm sometimes involves is allowing cell movement. By squeezing organelles to a particular part of the cell, cytoplasm can cause the cell to move within the blood flow. In humans, this allows white blood cells to get the parts of the body where they need to be in order to operate. In basic organisms, such as the amoeba, this provides their only means of transportation. In plants, this process, called cytoplasmic streaming, allows them to optimize cell organelles for the collection of sunlight necessary for photosynthesis.