Overview
This lecture reviews key cell organelles and structures, their functions in both prokaryotic and eukaryotic cells, and highlights their importance in cell and organism health.
Key Cell Structures
- All cells have a cell membrane, controlling entry/exit and maintaining homeostasis.
- Many prokaryotic cells and some eukaryotic cells (e.g., plant cells) have a cell wall for structural support and protection.
- Cytoplasm, found in all cells, refers to everything inside the cell except the nucleus and contains cytosol as the jelly-like substance.
- The cytoskeleton is part of the cytoplasm, supporting organelles.
Eukaryote-Specific Organelles
- Centrioles, in animal cells, are involved in cell division and come from the centrosome.
- Chloroplasts, present in plant cells, perform photosynthesis to make sugars.
- Endoplasmic reticulum (ER) comes in two types: rough ER (with ribosomes for protein synthesis) and smooth ER (makes lipids, detoxifies, ships materials).
- Golgi apparatus modifies, sorts, and packages cellular materials for delivery.
- Lysosomes, mainly in animal cells, contain enzymes for breaking down substances.
- Mitochondria, found in plant and animal cells, produce ATP, the cell's energy currency.
- The nucleus, present in plant and animal cells, houses DNA and controls cell activities.
- Vacuoles store materials (water, proteins, waste); central vacuole is large in plant cells, while animal cells have several smaller ones.
Universal Organelles
- Ribosomes, found in all cells, are responsible for protein synthesis.
Importance and Health Connections
- Proper organelle function is essential for cell and organism health.
- Diseases can result from dysfunction of the ER, mitochondria, or ribosomes.
- Studying organelles helps to understand and potentially treat related diseases.
Key Terms & Definitions
- Cell membrane — external barrier controlling material movement in and out of the cell.
- Cell wall — rigid outer layer providing structure and protection (in plants, some prokaryotes).
- Cytoplasm — all cellular material inside the cell except the nucleus.
- Cytosol — jelly-like fluid portion of the cytoplasm.
- Cytoskeleton — network of fibers supporting cell shape and organelles.
- Centrioles — structures that help organize cell division in animal cells.
- Chloroplast — organelle in plant cells for photosynthesis.
- Endoplasmic reticulum (ER) — network for synthesis and transport of proteins and lipids.
- Golgi apparatus — modifies, sorts, and ships proteins and lipids.
- Lysosome — organelle containing digestive enzymes.
- Mitochondrion — site of ATP (energy) production.
- Nucleus — stores DNA and directs cell activities.
- Ribosome — site of protein synthesis.
- Vacuole — storage organelle for various substances.
Action Items / Next Steps
- Practice identifying organelles and their functions in animal and plant cell diagrams.
- Review video content as needed for further clarification.
- Prepare for quizzes or tests by recalling each structure’s name and main function.