Overview
This lecture reviews key cell organelles and structures, highlighting their functions and importance in both prokaryotic and eukaryotic cells.
Cell Membranes & Boundaries
- The cell membrane is found in all cells and controls movement in/out, maintaining homeostasis.
- The cell wall provides structure and protection in most prokaryotic cells and some eukaryotic cells (like plants).
Structures for Support & Division
- Centrioles, found in animal cells, assist with cell division by forming spindle fibers.
- The cytoplasm is everything inside the cell except the nucleus and includes the jelly-like cytosol supporting organelles.
- The cytoskeleton (not described in detail here) also supports the cell's structure.
Organelles for Synthesis & Processing
- The endoplasmic reticulum (ER) in eukaryotes comes in two types: rough ER (makes protein) and smooth ER (makes lipids, detoxifies).
- The Golgi apparatus modifies, sorts, and packages materials for delivery throughout the cell.
Energy & Metabolism Organelles
- Chloroplasts (plants only) perform photosynthesis to make sugar.
- Mitochondria (in plants and animals) generate ATP via cellular respiration.
Storage & Digestion Structures
- Lysosomes contain enzymes that digest and break down substances, mainly in animal cells.
- Vacuoles store water, proteins, or waste; large central vacuole in plant cells, smaller ones in animal cells.
Control Centers & Protein Synthesis
- The nucleus stores DNA and controls cell activities; found in eukaryotic cells.
- Ribosomes (in all cells) make proteins.
Importance & Relevance
- Organelle function is essential for cell and organism health; dysfunction can cause diseases.
- Examples include disorders from ER, mitochondria, or ribosome malfunctions.
Key Terms & Definitions
- Cell membrane — external barrier controlling entry/exit of materials.
- Cell wall — outer structure for support/protection in some cells.
- Cytoplasm — contents of the cell excluding the nucleus.
- Cytosol — jelly-like fluid in cytoplasm.
- Centrioles — cell division structures in animal cells.
- Endoplasmic reticulum (ER) — network for processing and transporting molecules; rough makes protein, smooth makes lipids.
- Golgi apparatus — packages and distributes cell products.
- Chloroplast — organelle for photosynthesis in plants.
- Mitochondrion — powerhouse making ATP.
- Nucleus — DNA storage and control center.
- Ribosome — protein synthesis machinery.
- Lysosome — digests cellular waste and invaders.
- Vacuole — stores various substances.
Action Items / Next Steps
- Review cell diagrams and practice naming organelles and recalling their functions.
- Prepare for any upcoming quiz or test on cell structures and their roles.