Overview
This lecture explains the differences and similarities between prokaryotic and eukaryotic cells, and why this is important for understanding infections and cell biology.
Introduction: Infections and Treatments
- Ringworm is a fungal infection, not caused by a worm, and is treated with antifungals, not antibiotics.
- Antibiotics target bacteria by disrupting their cell functions, but do not work on fungal infections.
Prokaryotic vs. Eukaryotic Cells
- Prokaryotes include organisms in the domains Bacteria and Archaea; they are unicellular (single cell).
- Eukaryotes belong to the domain Eukarya and include protists, plants, animals, and fungi; they can be unicellular or multicellular.
- "Prokaryote" and "eukaryote" refer to organisms; "prokaryotic cell" and "eukaryotic cell" refer to their cell types.
Shared Features of All Cells
- Both prokaryotic and eukaryotic cells contain DNA (genetic material).
- Both cell types have ribosomes to make proteins.
- Both have cytoplasm (jelly-like fluid inside the cell).
- All cells have a cell membrane (plasma membrane) to control entry and exit of substances.
Differences Between Prokaryotic and Eukaryotic Cells
- Most prokaryotes have a cell wall; some eukaryotes (plants, fungi) have cell walls, but animal cells do not.
- Prokaryotic cells are generally smaller and simpler than eukaryotic cells.
- Prokaryotic cells lack a nucleus; their DNA is not enclosed within a membrane.
- Prokaryotic cells have no membrane-bound organelles.
- Eukaryotic cells have a nucleus containing their DNA.
- Eukaryotic cells contain membrane-bound organelles like mitochondria, endoplasmic reticulum, and Golgi apparatus.
- Plant eukaryotic cells may have chloroplasts, animal eukaryotic cells do not.
Importance of Cell Types
- All living things are made of prokaryotic or eukaryotic cells.
- Knowing the type of cell involved helps determine appropriate treatment for infections.
Key Terms & Definitions
- Prokaryote — organism with cells lacking a nucleus and membrane-bound organelles.
- Eukaryote — organism with cells containing a nucleus and membrane-bound organelles.
- Cell membrane (plasma membrane) — boundary controlling substance movement in and out of the cell.
- Ribosome — cell structure that makes proteins.
- Cytoplasm — jelly-like fluid inside cells.
- Cell wall — outer structure for support and protection in some cells.
- Nucleus — membrane-bound organelle containing DNA in eukaryotic cells.
- Membrane-bound organelle — specialized structure with its own membrane within eukaryotic cells.
Action Items / Next Steps
- Practice using vocabulary to compare and contrast prokaryotic and eukaryotic cells.
- Review which cell types are associated with different domains of life (Bacteria, Archaea, Eukarya).