The interior structures of this cell type are: the cytoplasm, the cytoskeleton, ribosomes nucleic acids, and granules.
The cytoplasm is the gel-like material that fills the interior of the cell. The interior cell structures are bathed in this material, which contains water and a variety of other molecules and ions. It allows for the movement of materials from one part of the organism to another, and helps maintain homeostasis for the cell.
Until recently, it was thought that prokaryotes did not possess a cytoskeleton. However, we now know that certain types of bacteria and Archaeans have cytoskeleton proteins that function in a similar manner to a cytoskeleton. These proteins, found in the cytoplasm, provide structural support and also play a role in the process of binary fission, a form of cell division.
These structures are composed of RNA (ribonucleic acid) and are found in the cytoplasm of the cell. In prokaryotes, individual ribosomes are composed of two subunits that combine and are utilized to create proteins for the cell. An average bacterium may contain up to 15,000 ribosomes. These structures are essential for the cell to manufacture proteins.
As you might expect, prokaryotes contain both DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). The DNA of most prokaryotes is contained on a single chromosome that forms a circle and is concentrated in an area referred to as the nucleoid. It is anchored directly to the plasma membrane and is suspended in the cytoplasm. The DNA carries the genetic information of the cell.
RNA is also found in prokaryotes in several different forms and is required for creating proteins.
Some bacterial cells will contain small circular pieces of DNA that are not part of the chromosome. This DNA is referred to as plasmid DNA and is able to be transferred from one bacterium to another through the conjugation pili discussed earlier. Plasmid DNA often contains information that will allow a bacterial cell to produce new proteins. For example, some plasmids allow bacteria to become resistant to a particular antibiotic.
Usually rounded in shape with a phospholipid bilayer, granules are found in large numbers in most bacteria. They can store nutrients, individual elements (such as sulfur), as well as gas. The number and size of these structures will vary with the species of bacterium.