Prokaryotes

Definition

Prokaryotes are unicellular organisms that lack a nucleus and membrane-bound organelles. They include bacteria and archaea, characterized by their simple cell structure.

5 Must Know Facts For Your Next Test

1. Prokaryotes have a single circular chromosome located in the nucleoid region.
2. They reproduce asexually through binary fission, a process where the cell divides into two genetically identical cells.
3. Gram-positive bacteria have thick peptidoglycan layers in their cell walls, which retain the crystal violet stain used in Gram staining.
4. Prokaryotes can live in diverse habitats including extreme environments such as hot springs, deep-sea vents, and acidic or alkaline waters.
5. Some prokaryotes form symbiotic relationships with other organisms, including mutualistic relationships like those found in human microbiomes.

Review Questions

• What is the main difference between prokaryotic and eukaryotic cells?
• How do Gram-positive bacteria differ from Gram-negative bacteria in terms of cell wall structure?
• Name at least two types of habitats where prokaryotes can thrive.

Related terms

Binary Fission:

A method of asexual reproduction in prokaryotes where the cell divides into two genetically identical daughter cells.

Peptidoglycan:

A polymer that forms a mesh-like layer outside the plasma membrane of most bacteria, providing structural strength.

Microbiome:

The collection of microorganisms living in association with an organism or environment, often playing crucial roles in health and ecological balance.