Cellular Function, Genetics, Immunity Study Guide PDF

Module 1 Study Guide: Cellular Function, Genetics, Immunity, Inflammation, Infectious Diseases, Special Populations The Cell and DNA: A Simple Guide Think of a cell as a tiny city, and I'll show you how it works. Two types of cells somatic cells and germ cells. The Basic Building Block: Your...

Module 1 Study Guide: Cellular Function, Genetics, Immunity, Inflammation, Infectious Diseases, Special Populations The Cell and DNA: A Simple Guide Think of a cell as a tiny city, and I'll show you how it works. Two types of cells somatic cells and germ cells. The Basic Building Block: Your Cells Imagine your body is made up of trillions of microscopic factories. Each one is a cell, and each has specific jobs to do. Inside each cell, you'll find: The nucleus: Think of it as the city hall, where all the important instructions (DNA) are kept Mitochondria: These are the power plants, turning food into energy. Plays a role in apoptosis cell death. They have their own DNA which supports endosymbiotic theory. Cell membrane: Like the city walls, controlling what goes in and out Cytoplasm: The streets and spaces between everything, filled with a jelly-like substance Lysosomes: Breakdown waste, damaged cells, and invading pathogens. Involved in programmed cell death. How Cells Make More Cells: The Cell Cycle Picture a cell going through four main stages, like seasons in a year: 1. First Growth (G1): The cell grows and does its daily work 2. DNA Copying (S): Like making a backup of all the city's blueprints 3. Second Growth (G2): Final preparations, double-checking everything 4. Division (M): The grand finale where one cell becomes two DNA, RNA, and the Cell's Instruction Manual Think of DNA as a cookbook filled with all your family recipes. It stays safe in the nucleus, never leaving. But when the cell needs to make something: 1. mRNA is like taking a photo of the recipe (copying from DNA)  2. tRNA is like your kitchen helpers, bringing ingredients (amino acids) where they need to go 3. Together, they help make proteins - the actual dishes (or cell parts) https://youtu.be/ZrCx98CtJ_4 Study Guide: Cellular Permeability and Diffusion Key Concepts 1. Cellular Permeability a. Definition: The ability of a cell membrane to allow certain substances to pass through while blocking others. b. Function: Regulates the internal environment of the cell by controlling what enters and exits. 2. Membrane Structure a. Gates: Specialized proteins located in the cell membrane that can open or close. b. Regulation: Gates are controlled by: i. Proteins: Can act as channels or carriers for specific substances. ii. Chemical Signals: Molecules that trigger the opening or closing of gates. iii. Electrical Charges: Changes in electrical potential across the membrane that can influence gate status. 3. Diffusion a. Definition: The movement of solutes from an area of higher concentration to an area of lower concentration. b. Importance: A fundamental process for the transport of substances within and between cells. Key Terms Solutes: Substances dissolved in a solution (e.g., salts, sugars). Concentration Gradient: The difference in concentration of a substance across a space. Important Processes Passive Transport: Movement of substances across the cell membrane without the use of energy, primarily driven by diffusion. Facilitated Diffusion: A form of passive transport that uses proteins to help move substances across the membrane. Review Questions 1. What is cellular permeability?  2. How do proteins regulate the gates in the cell membrane? 3. Describe the process of diffusion and its significance in cellular function. Summary Understanding cellular permeability and diffusion is crucial for grasping how cells maintain homeostasis and interact with their environment. Focus on the role of the membrane and the processes that regulate substance movement to prepare for further study. Feel free to use this study guide to enhance your understanding of cellular permeability and diffusion! If you need additional information or resources, let me know! Study Guide: Cellular Biology and Pathophysiology Key Concepts 1. Replication and Differentiation Replication: The process by which cells duplicate their DNA before cell division. Differentiation: The process by which unspecialized cells develop into specialized cells with distinct functions. 2. Proto-oncogenes Definition: Normal genes that promote cell growth and division. Role: When mutated, they can become oncogenes, leading to uncontrolled cell proliferation. 3. Neoplasms Definition: Abnormal tissue growth resulting from excessive cell division. Types: o Benign Neoplasms: Non-cancerous growths that do not invade surrounding tissues.  o Malignant Neoplasms: Cancerous growths that invade nearby tissues and can metastasize. 4. Cellular Adaptation and Damage Cellular Adaptation: Changes in cell structure or function in response to stress or environmental changes (e.g., hypertrophy, atrophy). Cellular Damage: Injury to cells that may lead to dysfunction or death, often caused by toxins, inflammation, or ischemia. 5. ROS (Reactive Oxygen Species) Free Radicals Definition: Highly reactive molecules that can damage cellular components. Sources: Metabolism, environmental toxins, and radiation. 6. Antioxidants Definition: Substances that neutralize ROS and protect cells from oxidative stress. Examples: Vitamins C and E, glutathione. 7. Inappropriate Apoptosis Definition: The process of programmed cell death that occurs inappropriately, leading to diseases such as neurodegeneration or cancer. 8. Gene Mutation Definition: Permanent alterations in the DNA sequence that can lead to changes in protein function and may cause diseases. 9. Malignant Neoplasms Characteristics: Rapid growth, invasion of surrounding tissues, and potential to metastasize to distant sites. 10. Genetic Disorders Marfan Syndrome: A genetic disorder affecting connective tissue, leading to cardiovascular, skeletal, and ocular issues. Neurofibromatosis: A genetic disorder causing tumors on nerve tissues, resulting in skin changes and potential neurological issues. PKU (Phenylketonuria): A metabolic disorder caused by a deficiency in the enzyme phenylalanine hydroxylase, leading to intellectual disability if untreated. Lupus: An autoimmune disease where the immune system attacks healthy tissues, causing inflammation and damage to multiple organ systems. Review Questions 1. What is the difference between proto-oncogenes and oncogenes? 2. Explain the significance of cellular adaptation and how it differs from cellular damage. 3. What role do antioxidants play in cellular health? 4. Describe the characteristics of malignant neoplasms compared to benign ones. 5. What are the clinical features of Marfan syndrome and neurofibromatosis? Summary This study guide covers fundamental concepts related to cellular biology and pathophysiology, including mechanisms of replication, differentiation, and the impact of genetic mutations on health. Understanding these concepts is crucial for recognizing how cellular processes contribute to disease states. Study Guide: Cell Membrane Transport, Energy Production, Protein Synthesis, Cellular Organization, and Disease Development Key Concepts 1. Substances Crossing the Cell Membrane Passive Transport: o Diffusion: Movement of molecules from an area of higher concentration to lower concentration (e.g., oxygen and carbon dioxide). o Facilitated Diffusion: Movement of molecules across the membrane via specific transport proteins (e.g., glucose transport). o Osmosis: Diffusion of water across a selectively permeable membrane. Active Transport: o Definition: Movement of substances against their concentration gradient, requiring energy (ATP). o Example: Sodium-potassium pump, which maintains the electrochemical gradient across the membrane. Endocytosis and Exocytosis: o Endocytosis: Process of engulfing substances into the cell (e.g., phagocytosis, pinocytosis). o Exocytosis: Process of expelling materials from the cell (e.g., neurotransmitter release). 2. Cellular Energy Source and Production ATP (Adenosine Triphosphate): The primary energy currency of the cell. Energy Production: o Glycolysis: The breakdown of glucose to produce ATP in the cytoplasm. o Krebs Cycle (Citric Acid Cycle): Occurs in the mitochondria, producing electron carriers (NADH and FADH2). o Electron Transport Chain: Located in the inner mitochondrial membrane, where ATP is produced through oxidative phosphorylation. 3. Process of Protein Synthesis Transcription: o Occurs in the nucleus where DNA is transcribed into messenger RNA (mRNA). Translation: o The mRNA is translated into a protein at the ribosome.  o Transfer RNA (tRNA) brings amino acids to the ribosome according to the codon sequence on the mRNA. Post-Translational Modifications: After synthesis, proteins may undergo modifications (e.g., phosphorylation, glycosylation) that affect their function and activity. 4. Cellular Organization Cell Types: o Prokaryotic Cells: Simple cells without a nucleus (e.g., bacteria). o Eukaryotic Cells: Complex cells with a nucleus and organelles (e.g., plant and animal cells). Tissue Organization: o Cells group together to form tissues (e.g., epithelial, connective, muscle, and nervous tissues). o Tissues combine to form organs, which then work together in organ systems. 5. Genetics, Epigenetics, and Environment in Disease Development Genetics: The study of heredity and the variation of inherited characteristics, including mutations that may lead to diseases. Epigenetics: Changes in gene expression that do not involve alterations to the underlying DNA sequence; influenced by environmental factors (e.g., diet, stress) and can be passed to offspring. Environmental Factors: External influences such as toxins, lifestyle, and socioeconomic status that can affect gene expression and disease risk. Review Questions 1. What are the differences between passive and active transport mechanisms? 2. Describe the steps involved in ATP production within the cell. 3. Outline the process of protein synthesis from transcription to post-translational modifications. 4. Compare and contrast prokaryotic and eukaryotic cells in terms of structure and organization. 5. How do genetics and epigenetics interact with environmental factors to influence disease development? Summary This study guide provides a comprehensive overview of critical cellular processes including how substances cross cell membranes, energy production mechanisms, protein synthesis, cellular organization, and the interplay of genetics, epigenetics, and environmental factors in disease development. Understanding these concepts is essential for exploring cellular biology and its implications in health and disease. If you have further questions or need clarification on any topic, don’t hesitate to ask! Mitosis vs. Meiosis: Two Ways to Divide Mitosis is like copying your favorite book exactly - you end up with two identical copies. This is how most of your body grows and repairs itself. Meiosis is more like shuffling a deck of cards and dealing them out. It's used to make reproductive cells (eggs and sperm), where you want to mix things up a bit. https://youtu.be/zrKdz93WlVk https://youtu.be/d_-XWjlhLyk When Things Go Wrong: Mutations and Errors Think of DNA as a long string of text: A mutation is like a typo that gets published in a book A DNA replication error is like making a mistake while copying text The difference? A mutation is permanent, while a replication error only affects one copy. Genes and Alleles: The Family Recipe Book A gene is like a complete recipe (say, for chocolate chip cookies) An allele is like a specific version of that recipe (chewy cookies vs. crispy cookies) How Traits Pass Down: Inheritance Imagine you're collecting trading cards: Dominant traits are like rare cards that always show up in your collection if you have even one Recessive traits are like common cards that only show up if you have two copies X-linked traits are special cards that work differently in boys and girls Cell Division and Body Balance Your body maintains balance (homeostasis) like a well-run restaurant: Old cells (like worn-out kitchen equipment) get replaced Growing areas need more cells (like adding tables to a busy section) Damaged cells get repaired or replaced (like fixing broken dishes) Quality Control: Cell Checkpoints Cells have security checkpoints, like airport security: They check if the DNA copied correctly They make sure the cell is big enough They verify everything is ready for division When these checkpoints fail, it's like security guards sleeping on the job - things can go wrong, sometimes leading to cancer. Cell Communication: The Cellular Conversation Fundamental Principles of Cell Communication What is Cell Communication? Scientific understanding defines cell signaling as the process by which cells: Interact with themselves Communicate with other cells Respond to environmental stimuli Communication Methods Types of Signaling 1. Direct Contact Signaling a. Cells touch directly b. Exchange molecular information c. Use protein channels and surface receptors 2. Chemical Signaling a. Release of signaling molecules b. Different communication ranges: c. Autocrine: Cell signals itself d. Paracrine: Nearby cells e. Endocrine: Distant cells via hormones Signaling Mechanisms Research highlights several key communication strategies: 1. Molecular Messengers a. Hormones b. Neurotransmitters c. Growth factors  d. Cytokines 2. Signaling Pathways a. Receptor activation b. Intracellular signal transmission c. Gene expression modification Cellular Signaling Pathways Key Molecular Players 1. Receptors a. Detect external signals b. Trigger internal responses c. Types: d. Surface membrane receptors e. Intracellular receptors 2. Second Messengers a. Amplify and transmit signals b. Examples: c. Cyclic AMP d. Calcium ions e. Inositol triphosphate Signaling Cascade 1. Signal Reception a. Ligand binds to receptor b. Receptor changes configuration 2. Signal Transduction a. Molecular chain reaction b. Protein kinase activation c. Phosphorylation events 3. Cellular Response a. Gene expression changes b. Protein synthesis c. Metabolic adjustments Advanced Communication Methods Emerging Research Insights Recent studies reveal: 1. MicroRNA Communication a. Genetic information exchange b. Intercellular messaging c. Epigenetic regulation 2. Extracellular Vesicles a. Membrane-enclosed packages b. Transport molecular information c. Facilitate long-distance communication Communication Breakdown: Disease Implications Disrupted Signaling Consequences 1. Cancer a. Uncontrolled cell proliferation b. Miscommunicated growth signals 2. Neurological Disorders a. Impaired neurotransmitter signaling b. Miscommunication between neurons 3. Autoimmune Conditions a. Misinterpreted cellular signals b. Inappropriate immune responses Understanding Genetics and Gene Editing: A Comprehensive Guide What is Epigenetics? Think of your genes as a vast library of books. Epigenetics is like the librarian who decides which books can be read and which stay locked away. According to the CDC, these changes begin before birth, helping determine whether cells become heart cells, nerve cells, or skin cells. It's not about changing the actual text of your genes, but rather controlling how they're read and expressed. The Environment-Gene Connection Your lifestyle and environment can influence how your genes behave, much like how weather affects a garden: Diet and nutrition Stress levels Physical activity Environmental exposures Early life experiences Research has shown that these factors can turn genes on or off, affecting health and potentially passing these changes to future generations. Gene Editing and CRISPR: The Ethics Debate The ability to edit genes raises complex ethical questions, similar to having the power to rewrite humanity's cookbook. Recent developments have highlighted several key ethical concerns: 1. Safety and Unintended Consequences a. Like editing a complex computer program, changing one part might affect others unexpectedly b. Long-term effects remain unknown 2. Access and Equality  a. Who gets access to these powerful technologies? b. Could this create new forms of inequality? 3. Future Generations a. Changes could affect children and grandchildren b. Questions about consent for hereditary modifications Genetic Testing: Understanding Your Code Modern genetic testing is like having different levels of magnification on a microscope. According to current medical practice, there are several types: 1. Diagnostic Testing a. Identifies specific genetic conditions b. Used when symptoms are present 2. Predictive Testing a. Assesses future health risks b. Helps with preventive care 3. Carrier Testing a. Determines if you carry genes for hereditary conditions b. Important for family planning Inheritance Patterns: How Traits Pass Down Dominant Traits Think of dominant traits as VIP guests at a party - they'll always get noticed even if only one copy is present. Examples include: Brown eyes Dimples Some forms of heart disease Recessive Traits Recessive traits are like shy guests - they only show up when there are two copies. Examples include: Blue eyes  Red hair Many metabolic disorders X-Linked Inheritance This is like having special instructions that travel on the X chromosome: Males have one X chromosome (from mom) Females have two X chromosomes (one from each parent) This is why conditions like colorblindness affect males more often Using Punnett Squares: A Genetic Calculator Punnett squares are like a genetic calculator that helps predict inheritance patterns. Here's how they work: Parent 1 (Aa) × Parent 2 (Aa) This shows: 25% chance (AA) - Dominant 50% chance (Aa) - Carrier 25% chance (aa) - Recessive The Future of Genetics Recent advances in CRISPR technology are revolutionizing genetic medicine. The field is expected to reach $8.1 billion by 2025, bringing both exciting possibilities and ethical challenges: 1. Personalized Medicine a. Treatments tailored to your genetic profile b. More effective, fewer side effects 2. Disease Prevention a. Earlier detection of genetic risks b. Better preventive strategies 3. Ethical Considerations a. Privacy concerns  b. Genetic discrimination c. Equal access to genetic technologies The Role of Genetic Counseling Think of genetic counselors as your personal genetic interpreters. They help: Understand test results Make informed decisions Navigate ethical considerations Plan for future health needs The Human Immune System: A Comprehensive Guide The Two-Tier Defense System Think of your immune system as a medieval castle with two lines of defense. According to recent research, these defenses work together but have distinct roles: Innate Immunity: The Outer Wall Physical barriers (skin, mucous membranes) Chemical barriers (stomach acid, enzymes) Cellular defenders (neutrophils, macrophages) Quick response but less specific Adaptive Immunity: The Elite Guards Highly specific responses Creates immunological memory Takes longer to activate Gets better with each exposure Comparison Table: Innate Immunity vs. Adaptive Immunity Feature Innate Immunity Adaptive Immunity The body's immediate, non-specific The body's specific Definition response response to pathogens Response Rapid (minutes to hours) Slower (days to weeks) Time Has memory (improves Memory No memory with re-exposure) Phagocytes (e.g., macrophages, B cells, T cells, and Key Cells neutrophils), natural killer cells, dendritic antigen-presenting Involved cells cells Antibody production, Physical barriers, chemical barriers, Mechanisms cell-mediated inflammatory response immunity Examples of Vaccination response, Inflammation, fever, phagocytosis Responses T cell activation The Cellular Army Innate Immune Cells 1. Neutrophils: First responders 2. Macrophages: The cleanup crew 3. Natural killer cells: Virus hunters 4. Dendritic cells: The messengers Adaptive Immune Cells 1. B lymphocytes: Antibody factories 2. T lymphocytes: The commanders a. Helper T cells: Strategy planners b. Killer T cells: Assassins c. Memory T cells: The record keepers The Molecular Arsenal Antibodies (Immunoglobulins) Research shows there are five main types: 1. IgG: The most common, provides long-term defense 2. IgA: Guards mucous membranes 3. IgM: First responder in new infections 4. IgE: Allergy and parasite fighter 5. IgD: The mysterious sentinel Chemical Signals (Cytokines) Think of these as the immune system's communication network: Interleukins: Coordinate immune responses Interferons: Anti-viral messages Tumor Necrosis Factor: Inflammation trigger The Complement System Like a cascade of dominoes, complement proteins: 1. Tag invaders for destruction 2. Attract immune cells 3. Create holes in bacterial cells 4. Help clear away debris Inflammation: The Body's Alert System According to current understanding, inflammation involves five cardinal signs: 1. Redness (Rubor) 2. Heat (Calor) 3. Swelling (Tumor) 4. Pain (Dolor)  5. Loss of function (Functio laesa) Key Mediators Histamine: Blood vessel dilator Prostaglandins: Pain and fever inducers Cytokines: Immune cell recruiters Hypersensitivity Reactions Clinical research identifies four main types: Type I (Immediate) Occurs within minutes Examples: Allergies, asthma Mediated by IgE Type II (Cytotoxic) Antibodies attack cells Examples: Blood transfusion reactions Mediated by IgG/IgM Type III (Immune Complex) Antibody-antigen deposits Examples: Lupus, rheumatoid arthritis Involves complement activation Type IV (Delayed) Takes 24-72 hours Examples: Contact dermatitis T-cell mediated The Immune Response in Action 1. Recognition Phase a. Pathogen detection b. Danger signal release 2. Activation Phase a. Immune cell recruitment b. Antibody production c. Inflammation initiation 3. Resolution Phase a. Pathogen elimination b. Memory cell formation c. Tissue repair Disorders of the Immune System 1. Autoimmune Disorders a. Body attacks itself b. Examples: Type 1 diabetes, rheumatoid arthritis 2. Immunodeficiencies a. Weakened defenses b. Can be inherited or acquired (like HIV) 3. Allergies and Hypersensitivities a. Overreactive responses b. Range from mild to life-threatening Clinical Applications 1. Vaccination a. Trains the immune system b. Creates immunological memory 2. Immunotherapy a. Enhances or suppresses immune responses b. Used in cancer and autoimmune treatment 3. Diagnostic Tools a. Antibody tests b. Immune cell counts  c. Inflammation markers Study Guide: The Immune System and Disease Prevention Key Concepts 1. Role of the Body's Normal Defenses in Preventing Disease Physical Barriers: Skin, mucous membranes, and secretions (e.g., saliva, tears) act as the first line of defense. Chemical Barriers: Antimicrobial substances and enzymes present in body fluids that inhibit pathogen growth. Cellular Defenses: White blood cells (leukocytes) such as phagocytes and natural killer cells that identify and destroy pathogens. 2. Innate vs. Adaptive Immunity Innate Immunity: o Definition: The body's immediate, nonspecific response to pathogens. o Characteristics: o Rapid response. o No memory (does not improve with repeated exposure). o Components include physical barriers, phagocytes, and inflammatory responses. Adaptive Immunity: o Definition: A specific response to pathogens that develops over time. o Characteristics: o Slower response initially but faster upon re-exposure (has memory). o Involves lymphocytes (B cells and T cells) that specifically target antigens. 3. Types of Vaccines and Their Use in Clinical Scenarios Live Attenuated Vaccines: Weakened forms of the virus or bacteria (e.g., MMR vaccine). They elicit strong immune responses and lifelong immunity but may not be suitable for immunocompromised individuals.  Inactivated Vaccines: Killed pathogens (e.g., polio vaccine). They are safer but may require booster shots for sustained immunity. Subunit, Recombinant, and Conjugate Vaccines: Use pieces of the pathogen (e.g., hepatitis B vaccine). They target specific parts of the pathogen and can be very effective with fewer side effects. mRNA Vaccines: Use messenger RNA to instruct cells to produce a protein that triggers an immune response (e.g., COVID-19 vaccines). They are a novel approach with rapid development capabilities. 4. Pathogenesis of Hypersensitivity Types of Hypersensitivity Reactions: o Type I (Allergic Reactions): IgE-mediated response (e.g., pollen allergies). o Type II (Cytotoxic Reactions): IgG or IgM antibodies bind to cell surface antigens (e.g., autoimmune hemolytic anemia). o Type III (Immune Complex-Mediated): Antigen-antibody complexes deposit in tissues (e.g., lupus). o Type IV (Delayed-Type Hypersensitivity): T-cell mediated (e.g., contact dermatitis). Mechanism: Each type involves different immune components and pathways, leading to varied clinical manifestations. 5. Altered Immune Responses and Common Disorders Systemic Lupus Erythematosus (SLE): An autoimmune disorder where the immune system attacks its own tissues, leading to inflammation and damage to multiple organ systems. HIV/AIDS: HIV attacks CD4+ T cells, leading to a weakened immune system and increased susceptibility to opportunistic infections and certain cancers. 6. Factors Enhancing and Impairing the Body's Defense Enhancing Factors: o Healthy diet, regular exercise, adequate sleep, vaccination, and good hygiene practices. Impairing Factors: o Chronic stress, poor nutrition, lack of sleep, certain medications (immunosuppressants), and underlying health conditions (e.g., diabetes). 7. Diagnostic and Treatment Considerations for Immune Disorders Diagnostic Approaches: o Blood tests (e.g., complete blood count, antibody tests). o Imaging studies for autoimmune diseases. o Skin tests for allergies. Treatment Options: o Immunotherapy for allergies and autoimmune conditions. o Antiretroviral therapy for HIV. o Vaccination as prevention for infectious diseases. Review Questions 1. What are the main differences between innate and adaptive immunity? 2. Describe the different types of vaccines and their appropriate clinical applications. 3. Explain the mechanisms involved in the various types of hypersensitivity reactions. 4. Discuss how altered immune responses manifest in disorders like lupus and HIV/AIDS. 5. Identify lifestyle factors that can enhance or impair the immune response. Summary This study guide is designed to provide an overview of the immune system's role in disease prevention, the differences between types of immunity, the importance of vaccines, and the understanding of hypersensitivity and immune disorders. Familiarity with these concepts is essential for recognizing and addressing various immune-related health issues. Study Guide: Interleukins, Inflammation, Infectious Diseases, and HIV Pathophysiology 6. Interleukins a. Main Interleukins Involved with Inflammation IL-1: Promotes inflammation and activates T cells. IL-6: Stimulates immune response and acute phase reactants. IL-8: Attracts neutrophils to sites of inflammation. IL-12: Enhances the activity of natural killer (NK) cells and T cells. b. Interleukins Associated with Autoimmune Diseases IL-17: Promotes inflammation and is associated with autoimmune conditions like rheumatoid arthritis and psoriasis. IL-21: Involved in the pathogenesis of autoimmune diseases such as systemic lupus erythematosus. 7. Allergy and Hypersensitivity Reactions Lab Values Indicating a Hypersensitivity Reaction: o Elevated Serum IgE Levels: Indicative of allergic responses. o Eosinophilia: Increased eosinophils in blood can suggest allergic or hypersensitivity reactions. Differentiation of PAMPs and DAMPs PAMPs (Pathogen-Associated Molecular Patterns): Molecules associated with groups of pathogens (e.g., bacterial cell wall components) that are recognized by the innate immune system. DAMPs (Damage-Associated Molecular Patterns): Molecules released by stressed or damaged cells that trigger immune responses. 9. Inflammation and Chronic Diseases Chronic inflammation can lead to tissue damage and is implicated in the development of various chronic diseases such as:  o Cardiovascular Diseases: Inflammation contributes to atherosclerosis. o Diabetes: Chronic low-grade inflammation can impair insulin signaling. o Cancer: Persistent inflammation can promote tumorigenesis. 10. Chain of Infection Definition: The process by which an infectious disease is transmitted. Components: o Pathogen: The infectious agent (e.g., bacteria, virus). o Reservoir: The natural habitat of the pathogen (e.g., humans, animals). o Portal of Exit: The way the pathogen leaves the reservoir (e.g., respiratory tract). o Mode of Transmission: How the pathogen is transferred (e.g., direct contact, airborne). o Portal of Entry: The way the pathogen enters a new host (e.g., mucous membranes). o Susceptible Host: An individual who can become infected. Example: Influenza virus transmission through respiratory droplets. 12. Gram-Negative vs. Gram-Positive Infections Gram-Negative: o Characteristics: Thin peptidoglycan layer, outer membrane, stain pink. o Example: Escherichia coli (E. coli). Gram-Positive: o Characteristics: Thick peptidoglycan layer, no outer membrane, stain purple. o Example: Staphylococcus aureus. Body Response: The immune system responds with inflammation, activating phagocytes and producing antibodies. Lab Values Indicating Infections: o Bacterial Infection: Elevated white blood cell count and neutrophils. o Viral Infection: Increased lymphocytes and normal to low white blood cell count. o Fungal Infection: Elevated eosinophils and specific fungal antibodies.  o Parasitic Infection: Elevated eosinophils and specific antibodies. 13. Comparison of Viruses and Bacteria Feature Viruses Bacteria Non-cellular, composed of RNA or Cellular, prokaryotic Structure DNA organisms Reproductio Requires host cell for replication Can reproduce independently n Antibiotics (specific to Treatment Antiviral medications bacteria) Not considered living (obligate Living Status Living organisms parasites) 14. Life Cycle of HIV Stages: o Attachment: HIV binds to CD4 receptors on T cells. o Fusion: The viral envelope fuses with the host cell membrane. o Reverse Transcription: Viral RNA is converted to DNA. o Integration: Viral DNA integrates into host DNA. o Replication: New viral particles are produced. o Budding: New virions are released from the host cell. Pathophysiology: HIV attacks CD4+ T cells, leading to immune system compromise. PrEP (Pre-Exposure Prophylaxis): An antiviral medication that prevents HIV replication, thus reducing the risk of infection when taken consistently. 15. Lab Values that Differentiate HIV/AIDS HIV: o Positive HIV antibody test. o Elevated viral load. o CD4+ T cell count >200 cells/mm³ indicates HIV infection.  AIDS: o CD4+ T cell count 500: Normal immune function b. 200-500: Compromised immunity  c.