Lecture Notes: Prokaryotic vs. Eukaryotic Cells

Overview

• Two major types of cells on Earth:
  • Prokaryotic Cells
  • Eukaryotic Cells

Prokaryotic Cells

• Definition: Simplest and most ancient cell type.
• Historical Significance:
  • Only form of life for billions of years.
  • Gave rise to eukaryotic cells.
• Size and Structure:
  • Smaller than eukaryotic cells.
  • Simple structure allows for rapid reproduction.
• Key Features:
  • Lack a nucleus (nucleoid region instead).
  • Open cell structure with no membrane-bound organelles.
  • Ribosomes scattered in the cytoplasm.
  • Cell wall surrounding plasma membrane (composition varies).
  • May possess flagella for movement.

Eukaryotic Cells

• Definition: More complex cells with a membrane-bound nucleus.
• Size and Structure:
  • Larger and more complicated than prokaryotic cells.
• Key Features:
  • Contain a true nucleus and membrane-bound organelles.
  • Can be single-celled or multicellular organisms.

Commonalities Between Prokaryotes and Eukaryotes

• Both have:
  • DNA as genetic material
  • Ribosomes
  • Cytoplasm
  • Plasma membrane

Differences Between Prokaryotes and Eukaryotes

• Age:
  • Prokaryotes: oldest type of cell
  • Eukaryotes: evolved from prokaryotes
• Cell Structure:
  • Prokaryotic: small and simple
  • Eukaryotic: larger and complex
• Nucleus and Organelles:
  • Prokaryotic: lack nucleus and membrane-bound organelles
  • Eukaryotic: have a nucleus and organelles
• Cell Type:
  • Prokaryotic: single-celled organisms
  • Eukaryotic: single-celled or multicellular
• DNA Organization:
  • Prokaryotic: usually a single, circular chromosome
  • Eukaryotic: organized as linear chromosomes

Conclusion

• Understanding differences and similarities helps in studying cell biology and evolution.