Prokaryotes and Eukaryotes
Prokaryotes are uni- or multicellular organisms made up of cells that do not have a nuclear envelope (pro – before, karyon – nucleus). The genetic material is not bound in a nucleus. They also lack cell organelles such as an endoplasmic reticulum, a Golgi apparatus, lysosomes, and mitochondria. Prokaryotes are divided into two main groups namely the Bacteria and the Archaea (ancient bacteria).
Eukaryotes are organisms that possess a membrane-bound nucleus that holds genetic material (eu – true, karyon – nucleus). Eukaryotes may contain other membrane-bound cell organelles, such as mitochondria and chloroplasts. Eukaryotic organisms can be unicellular or multicellular. Eukaryotes include organisms such as plants, animals, fungi, and protists.
Table: Differences between prokaryotes and eukaryotes.
|Small cells||Large cells|
|Unicellular or multicellular||Often (but not always) multicellular|
|Genetic material is not contained within a nucleus||Genetic material is contained in a membrane-bound nucleus|
|Cells have a simple membrane internal system but no organelles Example: no chloroplast, no mitochondria||Cells have a distinct membrane system with organelles Examples: Chloroplast, mitochondria, golgi bodies|