Inclusions

Definition

Inclusions are distinct intracellular structures found within prokaryotic cells that serve as storage vessels for nutrients, metabolic byproducts, and other substances. They help bacteria survive in fluctuating environmental conditions.

5 Must Know Facts For Your Next Test

1. Inclusions can store a variety of substances such as glycogen, polyphosphate, sulfur, and even gas vesicles for buoyancy.
2. Polyhydroxybutyrate (PHB) granules are a common type of inclusion used for carbon storage.
3. Gas vacuoles found in some aquatic prokaryotes allow them to regulate their buoyancy.
4. Magnetosomes are inclusions containing magnetic iron minerals that help certain bacteria orient themselves along the Earth's magnetic field.
5. Inclusions are not membrane-bound but are visible under light microscopy due to their high density.

Review Questions

• What types of substances can be stored in bacterial inclusions?
• How do gas vacuoles benefit aquatic prokaryotes?
• What is the function of magnetosomes in certain bacteria?

Related terms

Cytoplasm: The gel-like substance inside the cell where metabolic reactions occur.

Ribosome: Molecular machines within cells that synthesize proteins from amino acids.

Plasmid: Small, circular DNA molecules found in prokaryotes that replicate independently of chromosomal DNA.