Skip to content

Life Before a Nucleus – Prokaryotic and Eukaryotic Cell

Biology, Cell / By

Not all cells have a nucleus. Biology breaks cell types into –

(a) Prokaryotic cell

(Pro – before + karyon – nucleus) –

Those with no defined nucleus.

  • These cells are generally small, primitive and incomplete.
  • These cells do not have a well organized nucleus as nuclear membrane, nucleolus are absent.
  • The genetic material is a single chromosome lies in the cytoplasm. The undefined nuclear region in the cytoplasm is called nucleoid.
  • Cell organelles such as mitochondria, lysosome, endoplasmic reticulum, chloroplast etc. are not present.Examples – Bacteria and Blue-green algae.

 

More –

  1. Cell : The Fundamental Unit of Life
  2. Morphology of Cells – Size, Shape and Structure
  3. Outer membrane of Cell – Cell membrane / Plasma membrane
  4. Outer Membrane of The Cell – Cell wall


(b) Eukaryotic cell

(Eu – true + karyon – nucleus)

Those with a defined nucleus.

  • These cells are generally large, advanced and complete.
  • These cells  have a well organized nucleus as DNA is enclosed by a nuclear membrane and nucleolus is also present.
  • The genetic material is composed of two or more chromosomes.
  • Cell organelles such as mitochondria, lysosome, endoplasmic reticulum, chloroplast etc. are present in the cytoplasm.

Examples – Fungi, protozoa, higher advanced unicellular and multicellular animal and plant cells.

 

Read Next –

Nucleus