BIOLOGY 1 Cell Theory 1. All organisms are made up of cells. 2. Cells are the basic units of life. 3. Cells come from pre-existing cells that have multiplied. Hans and Zacharias Janssen (1595) Created the 1st compound microscope that has 2 lenses. Robert Hooke (1665) Coined the term “Cell” that comes from a Latin word [cella; room] Discovered the cell in the tissue of the cork/ slice of the cork. Antonie Van Leeuwenhoek (1674) Finds organism in a rain sample. He observed the free-living cell in water pond. Father of Microbiology Robert Brown (1831) Discovered nucleus Scottish botanist Theodore Schwann & Matthias Schleiden (1838-39) Cell theory that all animals and plants have cell Cell is the basic unit of life Theodore; observes the thin outer layer of cell that we call plasma/cell membrane Purkinje (1839) Coined the protoplasm Protoplasm is the cell membrane and nucleus for fluid substance of the cell Vladimir Zworykin (1940) Invented the Electron microscope Rudolf Virchow (1955) All cells come from free-existing cells Cell Structure and function Comprehensive list of cell organelles and their functions: 1. Nucleus- Function: Controls the cell's activities and contains genetic information (DNA). 2. Mitochondria- Function: Produces energy (ATP) through cellular respiration. 3. Endoplasmic Reticulum (ER) - Rough ER: Synthesizes and processes proteins. - Smooth ER: Involved in lipid and carbohydrate metabolism. 4. Ribosomes- Function: Synthesize proteins by linking amino acids together. 5. Golgi Apparatus (Golgi Complex)- Function: Modifies, sorts, packages, and transports proteins and lipids to their final destinations. 6. Lysosomes- Function: Contain enzymes for digesting waste materials and cellular debris. 7. Vacuoles (Plant cells have a large central vacuole)- Function: Store water, nutrients, and waste products. In plant cells, it helps maintain turgor pressure. 8. Cell Membrane (Plasma Membrane)- Function: Controls the passage of substances in and out of the cell, providing a barrier. 9. Cytoplasm- Function: Gel-like substance that fills the cell and provides support for organelles. 10. Cytoskeleton (composed of microfilaments, intermediate filaments, and microtubules)- Function: Provides structural support, maintains cell shape, and aids in cell movement. 11. Centrioles (Animal cells)- Function: Play a role in cell division (mitosis and meiosis). 12. Chloroplasts (Plant cells and some protists)- Function: Capture sunlight and perform photosynthesis to produce glucose (sugar). 13. Cell Wall (Plant cells, fungi, and some bacteria)- Function: Provides structural support and protection for the cell. 14. Nucleolus- Function: Responsible for the production of ribosomes. 15. Peroxisomes- Function: Break down fatty acids and detoxify harmful substances. 16. Flagella and Cilia (found in some cells)- Function: Assist in cell movement and the movement of materials around the cell. 17. Microvilli (found in some cells)- Function: Increase the surface area of the cell membrane for absorption. Eukaryotic Cells (10-100 micrometers): 1. **Nucleus:** - Structure: Membrane-bound organelle with DNA. - Function: Stores genetic information and controls cell activities. 2. **Membrane-Bound Organelles:** - Structure: Compartments enclosed by membranes. - Function: Specialized tasks like protein synthesis and energy production. 3. **Cell Membrane:** - Structure: Phospholipid bilayer with embedded proteins. - Function: Regulates substance movement, maintains cell integrity, and facilitates communication. 4. **Cytoplasm:** - Structure: Gel-like substance filling the cell. - Function: Houses organelles and supports cellular processes. 5. **Cytoskeleton:** - Structure: Protein filaments. - Function: Provides structure, maintains shape, and enables movement. Prokaryotic Cells (0.1-5.0 micrometers): 1. **Nucleoid Region:** - Structure: DNA region without a membrane. - Function: Stores genetic info and controls cell processes. 2. **No Membrane-Bound Organelles:** - Structure: Lack membrane-bound compartments. - Function: Cellular processes occur in the cytoplasm. 3. **Cell Envelope:** - Structure: Cell membrane and sometimes a cell wall. - Function: Protects the cell, regulates exchange, and offers support. 4. **Cytoplasm:** - Structure: Gel-like substance. - Function: Site for metabolic reactions. 5. **Ribosomes:** - Structure: RNA and protein particles. - Function: Site for making proteins. In summary, eukaryotic cells have a nucleus and membranebound organelles, while prokaryotic cells lack these features. Both have cell membranes, cytoplasm, and ribosomes but differ in complexity and organization. Cell Modifications Cells that have become differentiated to perform different functions Cell Cycle An orderly sequence of events that extends from the time a cell divides to form two daughter cells to the time those daughter cells divide again. Cell Cycle 1. **Interphase:** - **Cell Growth and Preparation:** Interphase is not a specific "season" but rather the longest phase of the cell cycle. It includes three main parts: G1 (Growth Phase 1), S (Synthesis), and G2 (Growth Phase 2). During interphase, the cell grows, carries out its normal functions, and replicates its DNA in preparation for cell division. 2. **G1 (Growth Phase 1):** - **Cell Growth:** This is the first part of interphase. The cell increases in size, makes new proteins, and prepares for DNA replication. 3. **S Phase (Synthesis):** - **DNA Replication:** In the S phase, the cell duplicates its DNA, resulting in two identical copies (chromatids) for each chromosome. This ensures that the two future daughter cells will have the same genetic information. 4. **G2 (Growth Phase 2):** - **Final Preparations:** During G2, the cell continues to grow and prepare for cell division. It checks and repairs DNA for any errors to ensure the genetic material is accurate. 5. **Mitosis:** - **Nuclear Division:** Mitosis is the process where the cell's nucleus (containing the duplicated DNA) divides into two nuclei, ensuring that each daughter cell gets an identical set of chromosomes. It's divided into several phases, including prophase, metaphase, anaphase, and telophase. 6. **Cytokinesis:** - **Cell Division:** Cytokinesis is the final step of the cell cycle. After mitosis, the rest of the cell, including the cytoplasm and organelles, is divided into two separate daughter cells. In animal cells, this often involves the formation of a cleavage furrow, while in plant cells, a cell plate is formed. 7. **Meiosis:** - **Specialized Cell Division (for Sexual Reproduction):** Meiosis is a process that occurs in specialized cells (germ cells) to produce reproductive cells (sperm and egg in animals, pollen and ovule in plants). It reduces the chromosome number by half, resulting in cells with half the usual genetic material. Meiosis includes two divisions (Meiosis I and Meiosis II) to produce four unique haploid cells. Meiosis is a kind of cell division happening during the formation of gametes in human. There are two rounds of cell division happening in meiosis and the resulting daughter cell is haploid (2n). Cell Membrane - The cell membrane, also known as the plasma membrane, is a fundamental structure in cells, serving as a protective barrier that separates the cell's internal environment from the external surroundings. It is a crucial component of all cells, whether they are prokaryotic (lacking a nucleus, like bacteria) or eukaryotic (containing a nucleus, like plant and animal cells). 1. **Phospholipid Bilayer:** The double layer of phospholipid molecules forming the main structure of the membrane. 2. **Integral Proteins:** Embedded within the membrane, they include transmembrane proteins (spanning the entire membrane) and are essential for transport and signaling. 3. **Peripheral Proteins:** Found on the inner or outer surface of the membrane, contributing to signaling, support, and cellular processes. 4. **Carbohydrates (Glycoproteins and Glycolipids):** Chains of carbohydrates attached to proteins and lipids on the outer surface, involved in cell recognition and adhesion. 5. **Cholesterol:** Scattered within the lipid bilayer, it maintains membrane fluidity and stability. 6. **Receptor Proteins:** Integral proteins binding to specific signaling molecules, triggering cellular responses. 7. **Transport Proteins:** Facilitate the movement of ions and molecules across the membrane, either actively or passively. 8. **Enzymes:** Proteins that catalyze chemical reactions at the cell's surface. 9. **Gated Ion Channels:** Specialized proteins allowing specific ions to pass in response to signals. 10. **Lipid Rafts:** Microdomains within the membrane organizing components and signaling. 11. **Cytoskeleton Attachments:** Proteins linking the membrane to the cytoskeleton for structural support. 12. **Extracellular Matrix Attachments (Animal Cells):** Proteins connecting the membrane to the extracellular matrix, providing structural support and signaling. transport mechanism (matter of you use energy or no use of energy/ no energy) process of how this substances went out and in to a cell. it has something to do with active and passive(diffusion greater concentration to lesser concentration, osmosis low concentration to greater concentration 1. isotonic - 2. hypertonic, hypotonic, facilitation diffusive - water enter this area by the use of other channel membrane ptotein) endocytosis- it is the process of getting inside the cell 1. pinocytosis - small particles 2. phagocytosis - large particles ## H2O ENZYME metabolism. - anabolism (Build up), catabolism (Break down) STRUCTURE OF ENZYMES, it is a protein, majority are protein but others are not protein in nature. The building blocks of protein (enzymes) is amino acid. REVIEW TYPES OF ENZYMES. cell types 1. **Prokaryotic Cells:** - Found in bacteria and archaea. - Lack a true nucleus; genetic material is in a nucleoid region. - Simpler structure with no membrane-bound organelles. - Single-celled organisms. 2. **Eukaryotic Cells:** - Found in plants, animals, fungi, and protists. - Have a true nucleus containing genetic material. - Complex structure with membrane-bound organelles. - Can be single-celled or multicellular. 3. **Animal Cells:** - Found in animals (including humans). - Eukaryotic cells. - Lack a cell wall but have a cell membrane. - Often round or irregular in shape. - May contain specialized structures like lysosomes. 4. **Plant Cells:** - Found in plants. - Eukaryotic cells. - Have a cell wall in addition to a cell membrane. - Typically have a regular, rectangular shape. - Contain chloroplasts for photosynthesis. 5. **Fungal Cells:** - Found in fungi (e.g., yeast, molds, mushrooms). - Eukaryotic cells. - Cell walls made of chitin. - Often grow as multicellular structures (hyphae) or singlecelled (yeast). 6. **Protist Cells:** - Found in diverse single-celled eukaryotic microorganisms. - Eukaryotic cells. - Highly variable in structure and function. - Include various groups like amoebas, algae, and protozoa. 7. **Nerve Cells (Neurons):** - Found in the nervous system of animals. - Specialized for transmitting electrical signals. - Long, branching extensions called dendrites and axons. 8. **Muscle Cells:** - Found in muscles. - Specialized for contraction and movement. - Can be striated (skeletal and cardiac muscle) or non-striated (smooth muscle). 9. **Blood Cells:** - Found in the circulatory system. - Include red blood cells (erythrocytes) for oxygen transport, white blood cells (leukocytes) for immune defense, and platelets for blood clotting. 10. **Plant Cell Types:** - Plant cells include parenchyma cells (general support and storage), collenchyma cells (flexible structural support), and sclerenchyma cells (rigid structural support). 11. **Immune Cells:** - Various types of white blood cells, such as macrophages, T cells, and B cells, play key roles in the immune system's defense against pathogens. 12. **Stem Cells:** - Stem cells are undifferentiated cells with the potential to develop into various cell types. They play crucial roles in development, tissue repair, and regenerative medicine. disorders and diseases that can result from the malfunction of cells during the cell cycle. 1. **Cancer:** Uncontrolled cell growth and division due to mutations that disrupt cell cycle regulation. Types of cancer include breast cancer, lung cancer, and leukemia. 2. **Genetic Disorders:** Genetic mutations can lead to conditions like Down syndrome, which result from abnormalities in cell division. 3. **Neurodegenerative Diseases:** Conditions like Alzheimer's and Parkinson's involve the accumulation of abnormal proteins within nerve cells, affecting cell cycle processes. 4. **Autoimmune Diseases:** Conditions like rheumatoid arthritis result from the immune system mistakenly targeting and damaging healthy cells. 5. **Cellular Senescence:** Aging-related changes in cell cycle regulation can contribute to age-related diseases, such as heart disease and osteoarthritis. Enzymes - are biological molecules known as proteins, and they play a crucial role in facilitating various chemical reactions in living organisms. Here are their key structures and functions: **Structure:** - Enzymes are typically large proteins with complex threedimensional structures. - They have an active site, a specific region where substrates (the molecules they act upon) bind. - Enzymes often have cofactors, which can be metal ions or organic molecules, to assist in catalyzing reactions. **Functions:** - **Catalysis:** Enzymes act as biological catalysts, increasing the rate of chemical reactions in cells. They lower the activation energy required for a reaction to occur, making it happen more efficiently. - **Specificity:** Each enzyme is highly specific, recognizing and binding to particular substrates based on their shape and chemical properties. - **Lock-and-Key Model:** Enzymes and substrates fit together like a lock and key. The enzyme's active site matches the shape and chemical properties of the substrate. - **Induced Fit:** The enzyme's active site may change its shape slightly upon substrate binding, creating a better fit and enhancing catalysis. - **Regulation:** Enzyme activity is often regulated by factors like temperature, pH, and regulatory molecules to ensure reactions occur when needed. - **Metabolism:** Enzymes play a central role in metabolic pathways, such as glycolysis, the citric acid cycle, and photosynthesis, helping break down or build complex molecules. - **Digestion:** Digestive enzymes (e.g., amylase, protease, lipase) break down food in the digestive system, enabling nutrient absorption. - **DNA Replication:** Enzymes like DNA polymerase are essential for DNA replication, ensuring the faithful copying of genetic information. - **Cell Signaling:** Kinases and phosphatases are enzymes involved in cell signaling, adding or removing phosphate groups from proteins to activate or deactivate them. oogenesis and spermatogenesis are the processes of gamete production in females and males, respectively. Oogenesis results in the production of relatively few large eggs, while spermatogenesis yields numerous small, motile sperm. These processes are vital for sexual reproduction, as they ensure the availability of mature gametes for fertilization and the development of new organisms.
