Overview
This lecture covers the fundamental structures of prokaryotic and eukaryotic cells, detailing their organelles, functions, and key differences.
Types of Cells
- Cells are classified into prokaryotic and eukaryotic types.
- Prokaryotic cells lack a nucleus and membrane-bound organelles.
- Eukaryotic cells have a nucleus and various membrane-bound organelles.
Prokaryotic Cell Structure
- Prokaryotes include bacteria and archaea.
- Key structures: plasma membrane, cytoplasm, ribosomes, and genetic material in a nucleoid.
- May have a cell wall, capsule, flagella, and pili.
Eukaryotic Cell Structure
- Eukaryotic cells contain a nucleus, mitochondria, endoplasmic reticulum (ER), Golgi apparatus, and sometimes chloroplasts.
- Animal cells have centrioles and lysosomes; plant cells have a cell wall, chloroplasts, and a central vacuole.
Organelle Functions
- Nucleus stores genetic material (DNA) and controls cell activities.
- Mitochondria are sites of cellular respiration and energy production.
- Endoplasmic reticulum (smooth and rough) synthesizes proteins and lipids.
- Golgi apparatus modifies, sorts, and packages proteins and lipids.
- Lysosomes contain digestive enzymes for waste breakdown.
- Chloroplasts (in plants) perform photosynthesis.
Differences Between Prokaryotic and Eukaryotic Cells
- Eukaryotic cells are generally larger and more complex than prokaryotic cells.
- Prokaryotic DNA is circular and free in the cytoplasm; eukaryotic DNA is linear and enclosed in the nucleus.
- Eukaryotes have organelles; prokaryotes do not.
Key Terms & Definitions
- Organelle — specialized cell structure that performs a specific function.
- Nucleus — membrane-bound organelle containing cell DNA.
- Mitochondria — organelle responsible for energy production.
- Chloroplast — plant cell organelle for photosynthesis.
- Prokaryote — cell without a nucleus or membrane-bound organelles.
- Eukaryote — cell with a nucleus and membrane-bound organelles.
- Cytoplasm — jelly-like fluid inside the cell.
Action Items / Next Steps
- Review diagrams of prokaryotic and eukaryotic cells.
- Compare organelle presence and functions in plant vs. animal cells.
- Prepare for quiz on cell organelle functions and differences between cell types.