Overview
This lecture covers the main structures of the plant cell and summarizes the function of each component.
Major Plant Cell Structures
- The plant cell is the basic unit of life in all plants.
- The cell wall is a rigid, cellulose-based structure that provides support and is permeable to fluids.
- The cell membrane (phospholipid bilayer) separates the cell from its environment and controls molecule flow.
- The cytoplasm includes all the contents inside the cell membrane, excluding the cell wall; organelles float in the cytosol (the fluid part).
- The large central vacuole stores materials and maintains plant shape by providing turgor pressure.
- The Golgi apparatus packages and modifies proteins and molecules for transport inside or outside the cell.
- Ribosomes synthesize proteins by translating RNA and can be free-floating or attached to the endoplasmic reticulum.
- Rough endoplasmic reticulum (rough ER) has ribosomes, produces and stores proteins, and sends them to the Golgi apparatus.
- Smooth endoplasmic reticulum (smooth ER) lacks ribosomes, produces lipids, and helps detoxify substances.
- The nucleus stores and protects DNA, which is transcribed into RNA to guide protein synthesis.
- Mitochondria produce ATP, providing energy for cell functions.
- Chloroplasts use sunlight to convert energy into carbohydrates, supplying usable energy for most living things.
- The cytoskeleton is a framework of microtubules and microfilaments that supports cell shape.
- Centrosomes produce microtubules and help organize cell division (mitosis).
Key Terms & Definitions
- Cell wall — rigid, cellulose-based outer layer providing structural support.
- Cell membrane — phospholipid bilayer that regulates entry and exit of substances.
- Cytoplasm — area inside the cell membrane containing all organelles and structures.
- Cytosol — fluid within the cytoplasm.
- Central vacuole — large storage organelle that supports plant structure.
- Golgi apparatus — organelle for packaging and modifying proteins and molecules.
- Ribosome — small structure that produces proteins from RNA instructions.
- Rough ER — endoplasmic reticulum with ribosomes, making and storing proteins.
- Smooth ER — endoplasmic reticulum without ribosomes, makes lipids and detoxifies.
- Nucleus — organelle storing DNA and directing cell activities.
- Mitochondrion — organelle producing cellular energy (ATP).
- Chloroplast — organelle converting sunlight into carbohydrates.
- Cytoskeleton — network providing cell shape and support.
- Centrosome — structure that organizes microtubules and assists in cell division.
Action Items / Next Steps
- Review key structures of plant cells and their functions for upcoming assessments.