Cells Unit Notes PDF

Cells Unit Notes 1. Characteristics of Cells Basic unit of life: All living organisms are made of cells. Cellular structure: Cells are microscopic and can be single-celled or multicellular. Perform vital functions: Growth, reproduction, respiration, and waste elimination. Cont...

Cells Unit Notes 1. Characteristics of Cells Basic unit of life: All living organisms are made of cells. Cellular structure: Cells are microscopic and can be single-celled or multicellular. Perform vital functions: Growth, reproduction, respiration, and waste elimination. Contain genetic material: DNA or RNA provides instructions for cellular processes. Organisms: Scientific term for “living things” MRS. GREN Movement Respiratory Sensitivity Growth Reproduction Excretion Nutrition 2. Cell Theory - The 3 Points 1. All living organisms are made of one or more cells. 2. The cell is the basic unit of life. 3. All cells are made from other cells. 3. Organelles in Plant and Animal Cells and Their Function Nucleus: Controls cell activities; contains genetic material. Mitochondria: Powerhouse of the cell; produces energy. Ribosomes: Protein synthesis. Endoplasmic Reticulum (ER): Transports materials (Rough ER has ribosomes; Smooth ER does not).  Golgi Apparatus: Packages and distributes proteins. Lysosomes: Break down waste (common in animal cells). Cell Membrane: Controls what enters and exits the cell. Vacuoles: Stores nutrients and waste (large central vacuole in plant cells). PLANT CELL ONLY: Chloroplasts: Photosynthesis (only in plant cells). Cell Wall: Provides structure and support (only in plant cells). PROKARYOTIC CELLS EUKARYOTIC CELLS Organisms that have prokaryotic cells are Organisms that have eukaryotic cells are called Prokaryotes called Eukaryotes Do not have a true nucleus Have a true nucleus Do not have organelles Have specialized organelles Smaller, less complex cells Larger, more complex cells Example- bacteria Example- animals, plants, fungi 4. How Osmosis and Diffusion Work Diffusion: Movement of molecules from a high to low concentration. Osmosis: Diffusion of water across a semipermeable membrane from low solute to high solute concentration. 5. The Meaning of Semi-Permeability and How It Relates to Cells Semi-permeability: Allows certain substances to pass while blocking others. Cell membrane: Semi-permeable; maintains homeostasis by controlling substance movement. Selectively Permeable – Allowing only certain materials to pass through. Permeable – Allowing materials to pass through. Impermeable – Allowing no material to pass through. 6. Similarities and Differences Between Osmosis and Diffusion Similarities: ○ Both are passive transport (no energy required). ○ Move substances down their concentration gradient. Differences: ○ Diffusion applies to all molecules, while osmosis is specific to water. ○ Osmosis occurs across a semipermeable membrane. OSMOSIS DIFFUSION Movement of a pure solvent (water) from a The spontaneous movement of molecules higher concentration to a lower concentration from a higher concentration to a lower concentration A semipermeable membrane is required May or may not require a semipermeable membrane It involves only the movement of solvent Both solute and solvent molecules move molecules 7. Difference Between Unicellular and Multicellular Organisms Unicellular: ○ Made of one cell. ○ Examples: Amoeba, bacteria. ○ Perform all life functions within one cell. Multicellular: ○ Made of many cells. ○ Examples: Humans, plants. ○ Cells specialize in different functions. Single-celled organisms rely on organelles to carry out life functions. Multi-celled organisms have specialized cells that work together in systems to carry out life functions such as digestion, breathing, and circulation. Cells, in a multicellular organism, begin alike, and then differentiate into specialized cells. The structure of each specialized cell is adapted for the task that it performs. 8. Cell Specialization Hierarchy: ○ Cell: Basic unit of life. ○ Tissue: Group of similar cells performing a specific function. ○ Organ: Structure made of tissues working together (e.g., heart, lungs). ○ Organ System: Group of organs performing complex functions (e.g., digestive system). ○ Organism: A complete living being. Order: Cell ➡ Tissue ➡Organ ➡Organ System ➡ Organism Refer here: Multicellular Organisms: Cells and Cell Systems Bacteria, amoeba, Paramecium, archaea, protozoa, unicellular algae, and unicellular fungi are examples of unicellular organisms. Unicellular organisms can move, reproduce and create energy just like multicellular organisms. The only function they cannot do is specialize. 9. Names of Major Organs From Some Organ Systems Respiratory System: Lungs, trachea. Circulatory System: Heart, blood vessels. Digestive System: Stomach, intestines, liver. Nervous System: Brain, spinal cord. Skeletal System: Bones, cartilage. 10. Advantages and Disadvantages of Cell Biology Advantages: ○ Helps understand diseases and develop treatments. ○ Explains growth, reproduction, and functions of organisms. ○ Medical Advancements: Helps develop new treatments for diseases (e.g., cancer, diabetes). Stem cell research can help repair damaged tissues or organs. ○ Improved Agriculture: Genetically modified organisms (GMOs) can help create crops resistant to pests, diseases, and environmental conditions. ○ Understanding Life: Helps us better understand how cells function and how diseases affect the body. ○ Regenerative Medicine: Regrowing tissues or organs using cells, helping people with injuries or conditions like organ failure. Disadvantages: ○ Requires advanced tools (e.g., microscopes). ○ Ethical concerns with experiments on cells. Ethical Issues: ○ Some people argue that certain cell research (e.g., embryonic stem cell research) is immoral or unethical. Unintended Consequences: ○ GMOs may have unknown effects on the environment or human health over time. Genetic Modification Risks:  ○ Gene editing (like CRISPR) could have unforeseen side effects or could be used in harmful ways (e.g., creating "designer babies"). Access and Equity: ○ Advanced cell therapies may only be accessible to certain people due to cost, leaving others without the benefits.