Overview
This lecture reviews key cell organelles and structures, their functions, and their importance in the overall health of cells and organisms.
Common Cell Structures
- All cells have a cell membrane, which controls what enters and exits the cell, maintaining homeostasis.
- Most prokaryotic cells and some eukaryotic cells (like plants) have a cell wall for shape and protection.
- Cytoplasm, present in all cells, is everything inside the cell except the nucleus and contains cytosol (jelly-like fluid).
Eukaryotic Cell Organelles
- Centrioles, found in animal cells, are involved in cell division by helping form spindle fibers.
- Chloroplasts, found in plant cells, carry out photosynthesis to produce sugar.
- Endoplasmic reticulum (ER) comes in rough (with ribosomes for protein synthesis) and smooth (makes lipids, detoxifies) forms, and transports materials within the cell.
- Golgi apparatus modifies, sorts, and packages materials for delivery.
- Lysosomes, mainly in animal cells, contain enzymes that break down waste and foreign substances.
- Mitochondria, found in plant and animal cells, produce ATP through cellular respiration.
- The nucleus, found in plant and animal cells, stores DNA and controls cell activities.
- Vacuoles, found in plant (one large central) and animal cells (smaller, several), store water, proteins, and waste.
Universal Organelle
- Ribosomes, found in all cells, build proteins.
Importance of Organelle Function
- Proper function of organelles is essential for cell and organism health.
- Malfunctioning organelles can cause diseases (e.g., ER disorders, mitochondrial disorders, ribosomopathies).
Key Terms & Definitions
- Cell membrane — boundary controlling entry/exit of substances in all cells.
- Cell wall — rigid support and protection, found in plants, fungi, and some prokaryotes.
- Cytoplasm — content of the cell excluding the nucleus; site of many metabolic reactions.
- Cytosol — fluid part of the cytoplasm.
- Centrioles — structures involved in cell division, found in animal cells.
- Chloroplast — organelle in plant cells for photosynthesis.
- Endoplasmic reticulum (ER) — network for protein/lipid synthesis and transport.
- Golgi apparatus — organelle that processes and ships proteins and lipids.
- Lysosome — enzyme-filled organelle for digestion.
- Mitochondrion — organelle producing cellular energy (ATP).
- Nucleus — controls cell activities and contains DNA.
- Ribosome — site of protein synthesis.
- Vacuole — storage organelle for substances like water and waste.
Action Items / Next Steps
- Practice naming organelles and recalling their functions using animal and plant cell diagrams.
- Review video content and notes for quiz or test preparation.