Overview
This lecture covers the structure and function of cells and their organelles, with a focus on cellular components, differences between plant and animal cells, and a 3-D cell model project.
Cell Structure and Function
- Cells are the basic structural and functional units of life.
- Most cells have three main parts: cytoplasm, cell membrane, and nucleus.
- The cytoplasm is where main life activities occur and contains organelles.
- The cell membrane is an elastic, differentially permeable double layer of fats and proteins protecting the cytoplasm.
- The nucleus contains genetic material (DNA), nucleolus, and chromosomes.
Major Cell Organelles and Functions
- Mitochondria: Produce ATP, release energy from food, known as the cell’s powerhouse.
- Lysosomes: Contain enzymes for digestion of carbohydrates, fats, and proteins.
- Peroxisomes: Break down fatty acids and amino acids; neutralize harmful free radicals.
- Golgi Bodies: Modify, sort, and package substances for secretion or use within the cell.
- Endoplasmic Reticulum (ER): Rough ER (with ribosomes) synthesizes proteins; Smooth ER (without ribosomes) produces lipids and detoxifies drugs.
- Ribosomes: Synthesize proteins from amino acids.
- Vacuoles: Store and transport food or water; contractile vacuoles expel excess water (protists).
- Vesicles: Store and move materials between organelles.
Nucleus and Genetic Material
- The nucleus is surrounded by a nuclear membrane with pores.
- The nucleoplasm suspends structures like the nucleolus and chromosomes.
- Chromosomes contain DNA, which carries genetic information for inheritance.
Cytoskeleton
- Provides cell shape, support, and movement.
- Microfilaments: Thin, flexible fibers (actin) for support and rigidity.
- Microtubules: Hollow tubes for structure, chromosome separation, vesicle movement.
- Intermediate Filaments: Provide structural framework.
Special Cell Structures
- Centrosome: Organizes microtubules; contains centrioles in animal cells.
- Cell Wall: Rigid structure for support in plants, fungi, and protists; made of cellulose (plants) or peptidoglycan (prokaryotes).
- Chloroplasts: Photosynthesis sites in plant cells, contain chlorophyll, have their own DNA.
- Central Vacuole: Regulates water concentration and supports expansion in plant cells.
Key Terms & Definitions
- Organelle — Specialized structure within a cell performing a specific function.
- Cytoplasm — Fluid and organelles between the cell membrane and nucleus.
- ATP — Adenosine triphosphate, energy currency of the cell.
- Differentially permeable — Allows some substances to pass more easily than others.
- Chromosome — Threadlike structure carrying genetic information in DNA.
- Microfilament — Polymer of actin providing cell support and movement.
- Microtubule — Tubular structure aiding in cell structure and transport.
- Chlorophyll — Green pigment in chloroplasts for photosynthesis.
Action Items / Next Steps
- Create a 3-D cell model using fruits and vegetables, ensuring accurate labeling and size (5-10 inches in diameter/height).
- Refer to lesson visuals for cell model accuracy.
- Follow rubric guidelines for project assessment.