Overview
This lecture reviews cell structure and function, detailing the main parts of prokaryotic and eukaryotic cells and their roles.
Cell Theory
- All living organisms are composed of cells.
- The cell is the basic unit of structure and function in living things.
- All cells arise from pre-existing cells.
Types of Cells
- Prokaryotic cells lack a nucleus and membrane-bound organelles (e.g., bacteria).
- Eukaryotic cells have a nucleus and membrane-bound organelles (e.g., plants, animals).
Prokaryotic Cell Structure
- Cell wall provides shape and protection.
- Plasma membrane controls transport in and out of the cell.
- Cytoplasm contains enzymes and cell components.
- Nucleoid is the region with genetic material (DNA).
- Ribosomes synthesize proteins.
- Some have pili for attachment and flagella for movement.
Eukaryotic Cell Structure
- Nucleus contains DNA and controls cell activities.
- Cytoplasm is the fluid containing organelles.
- Mitochondria produce energy (ATP) by cellular respiration.
- Endoplasmic reticulum (ER) transports materials; rough ER has ribosomes, smooth ER does not.
- Golgi apparatus modifies, sorts, and packages proteins.
- Lysosomes contain digestive enzymes (mainly in animal cells).
- Vacuoles store materials (large in plant cells).
- Chloroplasts carry out photosynthesis (in plant cells).
- Cell membrane regulates entry and exit of substances.
- Cell wall (in plants) supports and protects.
Key Terms & Definitions
- Organelle — specialized cell structure performing specific functions.
- Nucleus — membrane-bound organelle containing DNA.
- Mitochondria — organelle for energy production.
- Ribosome — site of protein synthesis.
- Plasma membrane — cell boundary controlling material movement.
- Cytoplasm — gel-like substance inside the cell.
Action Items / Next Steps
- Review diagrams of prokaryotic and eukaryotic cells.
- Memorize the function of each organelle.
- Complete assigned reading on cell structures.