Types of Cells: Prokaryotic vs. Eukaryotic

Overview

• Two major types of cells on Earth: Prokaryotic and Eukaryotic.
• Prokaryotic cells:
  • Simplest and most ancient.
  • Sole life form for billions of years.
  • Gave rise to eukaryotic cells.
• Eukaryotic cells:
  • Evolved from prokaryotic cells.

Prokaryotic Cells

• Size and Structure:
  • Smaller and simpler than eukaryotic cells.
  • Simple structure aids in rapid and effective reproduction.
• Internal Structure:
  • Lack nucleus; "prokaryote" means "before nucleus".
  • No membrane-bound organelles.
  • DNA located in the nucleoid region, not enclosed by a membrane.
  • Ribosomes scattered in cytoplasm.
• Cell Wall:
  • Surrounds plasma membrane.
  • Made of complex polysaccharides (varies between archaea and bacteria).
• Movement:
  • Possess flagella for movement.

Eukaryotic Cells

• Size and Structure:
  • Larger and more complex than prokaryotic cells.
  • Contain membrane-bound nucleus and organelles.
• Internal Structure:
  • "Eukaryote" means "true nucleus".
  • More complex internal organization.
• Cellularity:
  • Can be single-celled or multicellular.
• DNA Structure:
  • Organized as linear chromosomes.

Commonalities between Prokaryotic and Eukaryotic Cells

• Genetic Material:
  • Both use DNA as genetic material.
• Components:
  • Both have ribosomes.
  • Both contain cytoplasm.
  • Both have a plasma membrane.

Differences between Prokaryotic and Eukaryotic Cells

• Age and Complexity:
  • Prokaryotes are older, smaller, and simpler.
  • Eukaryotes evolved later, are larger, and more internally complex.
• Nucleus and Organelles:
  • Prokaryotes lack a nucleus and membrane-bound organelles.
  • Eukaryotes have both a nucleus and organelles.
• Cellularity:
  • Prokaryotes are single-celled.
  • Eukaryotes can be single-celled or multicellular.
• DNA Organization:
  • Prokaryotic DNA is a single, circular chromosome.
  • Eukaryotic DNA is organized in linear chromosomes.