Prokaryotic Organisms

Characteristics of Prokaryotic Organisms

General Properties

  • Prokaryotes are simple, unicellular organisms forming another essential group of living organisms.
  • The term Prokaryotic indicates organisms whose cells lack a nucleus and other membrane-bound organelles.
  • Bacteria and archaea are the two domains that make up prokaryotic organisms.

Cell Simplicity

  • Prokaryotic cells are typically smaller and simpler than eukaryotic cells.
  • They lack the organelles found in eukaryotic cells, such as the nucleus or mitochondria.
  • Despite their simplicity, prokaryotic cells are highly efficient, with all life processes occurring within the single cell.

DNA Structure

  • In contrast to eukaryotes, prokaryotic cells contain a circular DNA molecule that is located in the cytoplasm rather than enclosed in a nuclear envelope.
  • This region where DNA is found is referred to as the nucleoid.
  • Some prokaryotes also carry additional genetic information in structures called plasmids.


  • Prokaryotic organisms mainly reproduce through a type of asexual reproduction known as binary fission.
  • In this process, the cell’s DNA is copied, and the cell divides into two identical daughter cells.

Nutrition and Respiration

  • Prokaryotes can show different forms of nutrition: some are photosynthetic, some are chemosynthetic (derive energy from chemicals), others are heterotrophic.
  • While some prokaryotes in certain conditions can carry out aerobic respiration like eukaryotes, a significant number of prokaryotes are anaerobes, able to live without dependedance on oxygen.

Distribution and Diversity

  • Prokaryotic organisms are found in virtually all environments, from soil to human skin, to thermal vents on the ocean floor.
  • Their capacity for rapid reproduction and genetic variation makes them very adaptable, contributing immensely to the biodiversity of life on Earth.