Overview
This lecture reviews the functions of key organelles in eukaryotic cells and explains their roles in cell structure, protein/lipid production, and energy processes.
Organelle Functions
- The nucleus stores genetic material and coordinates cell activities, acting as the control center.
- Ribosomes are responsible for protein synthesis, meaning they make proteins.
- The rough endoplasmic reticulum (rough ER) transports proteins made by ribosomes to the Golgi apparatus.
- The smooth endoplasmic reticulum (smooth ER) synthesizes (makes) phospholipids, which are fats important for membranes.
- The Golgi apparatus modifies, folds, and packages proteins into vesicles for delivery to their destinations.
- Proteins are essential for all bodily processes, not just muscles; they include enzymes and structural components.
- Lysosomes act as the cell’s waste disposal, breaking down unwanted materials.
- Vacuoles provide structural support in plants and are used for storage and waste disposal.
- Plastids contain genetic material, and help in synthesis and storage (present in plants only).
- The cell wall is a rigid outer layer providing structural support in plant cells; animals lack cell walls but have membranes.
- Cytoskeleton supports cell structure, assists movement, and aids transport within the cell.
- Centrioles are involved in cell division (replication).
- Cilia and flagella are hairlike structures that help in cell movement.
- Mitochondria are the "powerhouse" of the cell, producing energy through respiration.
- Chloroplasts (in plants) convert light energy into usable energy via photosynthesis.
Key Terms & Definitions
- Organelle — specialized structure within a cell with a specific function.
- Nucleus — stores genetic information; controls cell processes.
- Ribosome — site of protein production (synthesis).
- Endoplasmic Reticulum (ER) — transports proteins (rough ER) and synthesizes lipids (smooth ER).
- Golgi Apparatus — modifies, folds, and ships proteins.
- Lysosome — breaks down cell waste.
- Vacuole — storage and structural support (mainly in plants).
- Plastid — organelle for synthesis and storage (plants only).
- Cell Wall — rigid outer support (plants only).
- Cytoskeleton — provides cellular structure and facilitates movement.
- Centrioles — structures key for cell division.
- Cilia/Flagella — structures for cell movement.
- Mitochondrion — site of energy production in cells.
- Chloroplast — site of photosynthesis in plants.
- Lipid — fat molecule; component of membranes.
Action Items / Next Steps
- Review and memorize the role of each organelle in eukaryotic and plant cells.
- Prepare answers for possible exam questions on organelle functions.
- Compare organelles in eukaryotic vs. prokaryotic cells.