Prokaryotic cells

Prokaryotic cells are a type of cell that lack a nucleus and other organelles due to the absence of a nuclear membrane. They are typically smaller and simpler than their counterparts, eukaryotic cells. Prokaryotic cells are found in bacteria and archaea, two of the three domains of life.

Characteristics

Prokaryotic cells are generally smaller than eukaryotic cells, typically ranging from 0.1 to 5.0 micrometers in diameter. They have a simple cell structure without many of the organelles found in eukaryotic cells. The most notable absence is the lack of a nucleus; instead, the genetic material is found in a region of the cell called the nucleoid.

Structure

Cell Wall

Most prokaryotic cells have a rigid cell wall that provides shape and protection. The cell wall composition varies between bacteria and archaea.

Plasma Membrane

The plasma membrane of a prokaryotic cell regulates the movement of substances in and out of the cell.

Cytoplasm

The cytoplasm of a prokaryotic cell is where the functions for cell growth, metabolism, and replication are carried out.

Genetic Material

Prokaryotic cells contain a single, circular DNA molecule in the nucleoid.

Reproduction

Prokaryotic cells reproduce asexually through a process called binary fission.

Classification

Prokaryotic cells are classified into two domains: Bacteria and Archaea. Bacteria are the most diverse and well-known group of prokaryotes, while Archaea are less well-known and are often found in extreme environments.

See Also

• Eukaryotic cells
• Cell biology
• Microbiology