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Cell Theory The cell wall is in plant cells not in animal cells Chloroplast is present in plant cells and is responsible for the green colour and photosynthesis All living things are composed of one or more cells. Cells originate from pre-existing cells, not from non-living matter. Cells are the fundamental units of life processes. Cell types Prokaryotes Simple, small cells without membrane-bound organelles. Contain ribosomes and are predominantly single-celled. Classified into two kingdoms: Bacteria and Archaea. Eukaryotes Complex cells with membrane-bound organelles. Larger in size compared to prokaryotes. Can be single-celled or multicellular, categorized into Protists, Fungi, Plants, and Animals. These are the four kingdoms. Mrs. Gren and Cell Functions Mrs. Gren Movement: All living things exhibit some form of motion. Respiration: Chemical process releasing energy from food. Word Equation: glucose + oxygen → carbon dioxide + water + energy Chemical Equation: C6H12O6 + O2 → CO2 + H2O + energy Sensitivity: Ability to detect and respond to environmental changes. Growth: Increase in size and development of living organisms. Reproduction: Passing genetic information to offspring, asexual and sexual methods. Word Equation: solar energy + carbon dioxide + water → glucose + oxygen Chemical Equation: Solar energy + CO2 + H2O → C6H12O6 + O2 Excretion and Nutrition Excretion: Elimination of waste from the body. Nutrition: Intake and utilization of nutrients for energy and growth. Photosynthesis: Process in plants converting solar energy, CO2, and water into glucose and oxygen. Importance of nutrients for cellular functions in plant and animal cells. Cell Processes and Reproduction Cell Division Essential for growth, repair, and reproduction in organisms. Multicellular organisms consist of multiple cells with specialized functions, and efficient nutrient and waste management through diffusion and osmosis. Diffusion and osmosis facilitate nutrient intake and waste removal in cells. Diffusion: Movement of substances from high to low concentration. Osmosis: Movement of water from high to low concentration. Examples of Cell Division in Repair: Gecko tail regrowth Bone repair Skin cell replacement Reproduction Types Asexual Reproduction: Single-celled and multicellular organisms produce genetically identical offspring. Sexual Reproduction: Involves two parents, combining genetic information in offspring. Efficiency of diffusion and osmosis about cell size and function. Cell Cycle and Mitosis Purpose of Mitosis Create two identical daughter cells. Cell Cycle Phases Interphase:(G1, S, G2, Checkpoints to ensure proper division and function) Cell growth, organelle replication, and preparation for division. Mitosis: Ensures each new cell receives a complete set of DNA instructions. Cytokinesis: Division of cytoplasm and organelles, completing cell division. Mitosis Process Prophase: Chromatin condenses, spindle fibres form, nuclear membrane dissolves. Metaphase: Chromosomes align along the cell's center. Anaphase: Sister chromatids separate and move to opposite ends. Telophase: Chromosomes unravel, spindle fibres dissolve, and nuclei reform. Lifespans of Cells Brain cells: 60 years/never Red blood cells: 120 days Stomach lining: 2 days Skin cells: 20 days Cancer and Cell Abnormalities Cancer Development Benign and malignant tumour distinctions in cancer. Cancer cells exhibit abnormal shapes and characteristics. Causes of cancer, include mutations and external factors like radiation and chemicals. Cancer Stages and Diagnosis Stages of cancer progression from localized to advanced metastasis. Diagnosis methods for detecting cancerous growths. Role of mutations, carcinogens, and genetic inheritance in cancer development. Cancer Diagnosis Endoscopy Uses a fibre optic cable with a camera to examine internal structures. Medical Imaging Utilizes x-rays, ultrasounds, CT scans, or MRI machines to detect lumps or masses. Biopsy Involves surgery to obtain tissue samples for analysis. Helps determine cancer spread and lymph node involvement. Cancer Treatment Surgery Effective when tumours are visible and accessible. Challenges in treating brain tumours due to complex anatomy. Radiation Disrupts mitosis and cell division to halt cancer cell growth. Causes chromosomes to align and kills abnormal daughter cells. Chemotherapy Involves drug therapy affecting all nearby cells. Halts cell division, impacting hair follicles and healing speed. Other Treatments Includes biophotonics, immunotherapy, and hormone therapy.’ Cancer Screening Purpose Detects cancer in asymptomatic individuals. Does not prevent cancer and may not detect all cases. Examples PAP test for cervical/prostate cancer detection. PSA test for prostate/cervical cancer via blood analysis. Blood tests and skin checks for colon and skin cancer screening. ABCD method for cancer detection based on asymmetry, border, colour, and diameter. Stem Cells and Cell Differentiation Stem Cells Unspecialized cells with rapid division. Embryonic stem cells can differentiate into any cell type. Cell Differentiation Process assigning cells specific functions. Embryonic stem cells differentiate during early embryo development. Stem Cell Research Applications in cord blood banking, tissue transplants, and regeneration. Potential for 3D organ printing using stem cells. Cell Division and Mitosis Cell Cycle and Mitosis The cell cycle is crucial for growth and development, involving nuclear and cell division. Interphase consists of G1 (cell growth), S (DNA replication), and G2 (preparation for mitosis). Mitosis ensures each new cell receives a full set of DNA instructions. Cytokinesis divides the cytoplasm and organelles, completing cell division. Mitosis Process Prophase: Chromatin condenses into chromosomes, centrioles move, and spindle fibres form. Metaphase: Chromosomes align along the center with spindle fibres attached. Anaphase: Sister chromatids separate and move to opposite ends of the cell. Telophase: Chromosomes unravel, spindle fibres dissolve, and the nuclear membrane reforms. Cellular Lifespan and Abnormal Cell Growth Cell Lifespan and Death Different cells have varying lifespans, e.g., red blood cells live for 120 days. Cells die due to aging, damage, or being no longer needed for function. Approximately 3 million cells die per minute in the human body. Abnormal Cell Growth and Cancer Cancer results from abnormal cell division that can lead to tumour formation. Cancer cells lack growth stoppers, allowing uncontrolled growth. Carcinogens like radiation, viruses, and chemicals can increase cancer risk. Stem Cells and Cell Specialization Stem Cells and Differentiation Stem cells are unspecialized cells that can divide rapidly and have no specific function. Cell differentiation assigns cells specific functions, leading to specialized cells. Embryonic stem cells can differentiate into any cell type in the body. Cell Specialization and Hierarchy Specialized cells perform specific functions. Red Blood Cells: Transport oxygen. Mucus Membranes: Produce mucus, and protect surfaces. Muscle Cells: Enable movement. Sperm Cells: Reproduction. Nerve Cells (Neurons): Transmit signals. Cells organize into tissues, which form organs, and then organ systems. Cells: Basic unit of life. Tissues: Groups of similar cells. Organs: Groups of tissues. Organ Systems: Groups of organs. Specialized Plant Cells Photosynthesis Cells: Contain chloroplasts. Water Transport Cells: Elongated, less green. Root Cells: Increase surface area for absorption. Hierarchy in cells involves complex structures at the top and simpler ones at the bottom. Microscopes Parts and Functions Parts of a Microscope Eyepiece (Ocular Lens): The lens you look through, usually with a magnification of 10x. Objective Lenses: Usually three or four lenses with different magnifications (4x, 10x, 40x, and sometimes 100x for oil immersion). Stage: The flat platform where the slide is placed. Stage Clips: Hold the slide in place on the stage. Diaphragm or Iris: Adjusts the amount of light that reaches the slide. Light Source: Illuminates the specimen from below. Base: Supports the microscope. Arm: Connects the base to the head and eyepiece. Coarse Focus Knob: Moves the stage up and down for general focusing. Fine Focus Knob: Fine-tunes the focus after using the coarse focus knob. Nosepiece: Holds the objective lenses and allows you to switch between them. Condenser: Focuses light onto the specimen. Function of Microscope Parts Eyepiece (Ocular Lens): Magnifies the image produced by the objective lens. Objective Lenses: Provide different levels of magnification to view the specimen in detail. Stage: Holds the slide and allows for movement to view different parts of the specimen. Stage Clips: Secure the slide in place. Diaphragm/Iris: Controls light intensity and contrast. Light Source: Provides illumination for viewing the specimen. Base: Stabilizes the microscope. Arm: Provides support and is used for carrying the microscope. Coarse Focus Knob: Quickly brings the specimen into general focus. Fine Focus Knob: Provides precise focusing adjustments. Nosepiece: Rotates to switch between objective lenses. Condenser: Concentrates light on the specimen to enhance visibility. Magnification Calculation To calculate the total magnification of a microscope, multiply the magnification of the eyepiece by the magnification of the objective lens being used. Low Power: Eyepiece (10x) × Low Power Objective (4x) = 40x Medium Power: Eyepiece (10x) × Medium Power Objective (10x) = 100x High Power: Eyepiece (10x) × High Power Objective (40x) = 400x