What Is the Cell Structure of Archaea?

Archaea have been known to exist in harsh environments such as near volcano vents.

In the late 1970s, Dr. Carl Woese and his associates at the University of Illinois rocked the scientific community with the discovery of a new group of organisms. Once thought to be part of the eubacteria, or bacteria domain, the archaea's cellular makeup warranted the creation of a third type--or domain--of life.

Size

Archaea are slightly less than 1 micron long. A micron is 1/1,000 of a millimeter. In order to see their cellular features, scientists use powerful electron microscopes.

Shape

Shapes can be spherical or ball shaped and are called coccus. Others are rod shaped, long and thin, and labeled bacillus. Variations of cells have been discovered in square and triangular shapes.

Locomotion

Some archaea have flagella, hair-like structures that assist in movement. There can be one or many attached to the cell's outer membrane. Protein networks can also be found on the cell membrane, which allow cells to attach themselves in groups.

Cell Features

Within the cell membrane, the archaea cell contains cytoplasm and DNA, which are in single-looped forms called plasmids. Most archaeal cells also have a semi-rigid cell wall that helps it to maintain its shape and chemical balance. This protects the cytoplasm, which is the semi-liquid gel that fills the cell and enables the various parts to function.

Phospholipids

The molecules that make up cell membranes are called phospholipids, which act as building blocks for the cell. In archaea, these molecules are made of glycerol-ether lipids. It is a stronger bond than that found in the cells of bacteria and the eukaryotes, which are the higher forms of life that include us.

Ether Bonding

The ether bonding makes it possible for archaea to survive in environments that are extremely acidic or alkaline, or that have great extremes in temperature. They have been found in deep ocean habitats near volcano vents that are releasing lava and gases.

References

• Was Darwin Wrong?: Carl Woese: from scientific dissident to textbook orthodoxy
• UCMP Berkeley.edu: Archaea: Morphology
• UCMP Berkeley.edu: Introduction to the Archaea