Overview
This lecture explains the key differences and similarities between prokaryotic and eukaryotic cells, highlighting their structures, functions, and significance in distinguishing between types of organisms and infections.
Prokaryotes vs Eukaryotes: Definitions & Domains
- Prokaryotes are single-celled organisms found in the domains Bacteria and Archaea.
- Eukaryotes belong to the domain Eukarya, including protists, plants, animals, and fungi.
- Eukaryotes can be unicellular or multicellular.
Similarities Between Prokaryotic and Eukaryotic Cells
- Both cell types have DNA, which serves as genetic material.
- Both have ribosomes, responsible for protein synthesis.
- Both contain cytoplasm, the jelly-like interior of the cell.
- Both have a cell membrane (plasma membrane) that controls entry and exit of substances to maintain homeostasis.
- Most prokaryotic cells and some eukaryotic cells (e.g., plants, fungi) have cell walls, but animal cells do not.
Differences Between Prokaryotic and Eukaryotic Cells
- Prokaryotic cells lack a nucleus; their DNA is not enclosed in a membrane.
- Eukaryotic cells have a nucleus that contains their DNA.
- Prokaryotic cells lack membrane-bound organelles (e.g., mitochondria, endoplasmic reticulum, Golgi apparatus).
- Eukaryotic cells possess various membrane-bound organelles, depending on the cell type (e.g., plant cells have chloroplasts).
- Eukaryotic cells are typically larger and more complex than prokaryotic cells.
Importance of Differences
- Antibiotics are effective against bacteria (prokaryotes) but not fungi (eukaryotes).
- Antifungal treatments target eukaryotic fungal cells.
- Recognizing cell type is important for treatment decisions and understanding organism diversity.
Key Terms & Definitions
- Prokaryote — An organism whose cells lack a nucleus and membrane-bound organelles.
- Eukaryote — An organism whose cells have a nucleus and membrane-bound organelles.
- Ribosome — Cell structure that synthesizes proteins.
- Cytoplasm — Jelly-like fluid inside cells.
- Cell membrane (plasma membrane) — Barrier controlling movement of substances in/out of the cell.
- Cell wall — Rigid outer layer found in most prokaryotes and some eukaryotes (plants, fungi).
- Nucleus — Membrane-bound organelle that houses DNA in eukaryotic cells.
- Membrane-bound organelle — Organelle surrounded by its own membrane (e.g., mitochondria, chloroplasts).
Action Items / Next Steps
- Practice using vocabulary words to compare and contrast prokaryotic and eukaryotic cells.
- Review examples of organisms in each domain and cell type.