Prokaryotic Cells: Simple, unicellular organisms that lack a nucleus and membrane-bound organelles. Examples include bacteria and archaea.
Eukaryotic Cells: Complex cells that contain a nucleus and other membrane-bound organelles. Found in plants, animals, fungi, and protists.
Key Organelles and Their Functions:
Nucleus: Contains genetic material (DNA) and controls cell activities.
Mitochondria: The powerhouse of the cell, responsible for energy (ATP) production through cellular respiration.
Rough Endoplasmic Reticulum (ER): Studded with ribosomes; involved in protein synthesis and transport.
Ribosomes: Sites of protein synthesis.
Smooth Endoplasmic Reticulum (ER): Involved in lipid synthesis and detoxification.
Golgi Apparatus: Modifies, sorts, and packages proteins for secretion or use within the cell.
Lysosomes: Contain digestive enzymes for breaking down waste and cellular debris.
Vacuoles: Store nutrients, waste products, and help maintain cell rigidity.
Chloroplasts: Site of photosynthesis in plant cells, containing the pigment chlorophyll.
Stem Cells:
Mitosis: The process of cell division that results in two identical daughter cells.
Differentiation: The process by which stem cells develop into specialized cell types.
Unipotent Stem Cells: Can differentiate into only one type of cell.
Multipotent Stem Cells: Can differentiate into a limited range of cell types.
Pluripotent Stem Cells: Can differentiate into almost all types of cells.
Totipotent Stem Cells: Can differentiate into any type of cell, including placental cells.
Hierarchical Organization:
Cells: The basic unit of life.
Tissues: Groups of similar cells working together to perform a specific function.
Organs: Structures composed of multiple tissue types working together.
Organ Systems: Groups of organs working together to perform complex functions.
Cell Membrane Structure (Fluid Mosaic Model):
Composed of phospholipids, proteins, cholesterol, and glycoproteins.
Phospholipid Bilayer: A double layer that forms the basic structure of the membrane, with hydrophilic heads and hydrophobic tails.
Protein Channels: Facilitate the movement of substances across the membrane.
Cholesterol: Stabilizes the membrane by maintaining its fluidity.
Transport Mechanisms:
Active Transport: The movement of substances against a concentration gradient, requiring energy (e.g., protein-mediated active transport, endocytosis, exocytosis).
Passive Transport: The movement of substances down a concentration gradient, without energy input (e.g., osmosis, simple diffusion, facilitated diffusion).
Surface Area-to-Volume Ratio: Affects the rate of diffusion; as the size of a cell increases, the surface area-to-volume ratio decreases, limiting the efficiency of diffusion.
Cell Theory: The fundamental concept in biology that states that all living organisms are made of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells.
Organism: An individual living entity that is capable of carrying out all the functions of life, including growth, reproduction, and metabolism.
Metabolism: The set of life-sustaining chemical reactions that occur within cells, including processes like respiration and photosynthesis.
Tissue Types:
Epithelial Tissue: Covers and protects body surfaces and lines internal organs and cavities.
Connective Tissue: Provides support and structure to the body, including bone, blood, and adipose tissue.
Muscle Tissue: Specialized for contraction and movement; types include skeletal, cardiac, and smooth muscle.
Nervous Tissue: Transmits electrical signals throughout the body, consisting of neurons and supporting cells.
Osmosis: The movement of water molecules across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration.
Diffusion: The passive movement of particles from an area of higher concentration to an area of lower concentration, driven by concentration gradients.
Facilitated Diffusion: A type of passive transport that requires specific transport proteins to help move substances across the cell membrane, without the need for energy.
Endocytosis and Exocytosis:
Endocytosis: The process by which cells engulf external substances, bringing them into the cell.
Exocytosis: The process by which cells expel substances from the cell by vesicles fusing with the membrane.
Homeostasis: The maintenance of a stable internal environment within an organism, necessary for proper cell function. Examples include temperature regulation and pH balance.
Surface Area-to-Volume Ratio (SA:V): The relationship between the surface area of a cell and its volume, which influences the rate of diffusion and the efficiency of material exchange with the environment.
Gene Expression: The process by which information from a gene is used to synthesize functional products, usually proteins, that contribute to the cell's function and structure.
Apoptosis: Programmed cell death, a natural process that helps maintain healthy tissue function by eliminating damaged or unnecessary cells.
Cellular Respiration: The process by which cells break down glucose and other nutrients to produce energy (ATP), involving stages such as glycolysis, the Krebs cycle, and oxidative phosphorylation.
Photosynthesis: The process by which plants and some other organisms convert light energy, usually from the sun, into chemical energy stored in glucose, using carbon dioxide and water.
Cell Communication: The process by which cells communicate with each other to coordinate activities, using molecules such as hormones, neurotransmitters, and signaling proteins.
Chlorophyll: A pigment in plant cells that captures light energy for photosynthesis, particularly important for the conversion of light energy into chemical energy.
Plasmid: Small, circular DNA molecules found in prokaryotic cells, often carrying genes that provide a survival advantage (e.g., antibiotic resistance).
Cell Cycle: The series of phases (interphase, mitosis, and cytokinesis) through which a cell progresses as it grows, duplicates its DNA, and divides into two daughter cells.
Nucleolus: A small, dense structure found within the nucleus of eukaryotic cells, involved in the synthesis of ribosomal RNA and the assembly of ribosome subunits.
Cytoskeleton: A network of protein filaments and tubules within the cytoplasm that provides structural support, helps with intracellular transport, and enables cell movement.
Lysosome: An organelle containing digestive enzymes that break down waste materials, cellular debris, and foreign pathogens within the cell.
Glycoproteins: Proteins that have carbohydrate groups attached to them, playing important roles in cell recognition, signaling, and adhesion.
Excretion: The process of removing metabolic waste products from an organism, essential for maintaining homeostasis. In humans, this occurs primarily through the kidneys and lungs.
Chloroplasts: Organelles in plant cells that contain chlorophyll and are responsible for carrying out photosynthesis.
Diffusion Gradient: The difference in concentration of a substance across a space or membrane, driving the movement of particles from areas of high to low concentration.
Topic 2: Exchange of Nutrients and Wastes
Carbohydrates: Organic compounds made of carbon, hydrogen, and oxygen that serve as a primary source of energy for living organisms. They include sugars, starches, and cellulose.
Proteins: Large molecules made up of amino acids; essential for cell structure, function, and regulation, as well as in catalyzing biochemical reactions (enzymes).
Lipids: Fatty substances that are insoluble in water, including fats, oils, and phospholipids. They are important for energy storage, insulation, and cell membrane structure.
Amylase: An enzyme that catalyzes the breakdown of starch into sugars in the mouth and small intestine.
Protease: An enzyme that breaks down proteins into amino acids, functioning in the stomach and small intestine.
Lipase: An enzyme responsible for breaking down fats (lipids) into fatty acids and glycerol.
Exchange surfaces: Special structures in the body that maximize the rate of material exchange, such as the villi in the intestines and the alveoli in the lungs.
Villi: Small finger-like projections in the lining of the small intestine that increase surface area for nutrient absorption.
Capillaries: Small blood vessels where the exchange of gases, nutrients, and wastes occurs between blood and tissues.
Closed circulatory system: A circulatory system where blood is contained within vessels and pumped by the heart to circulate throughout the body. This allows for more efficient transport of materials.
Nephron: The functional unit of the kidney, involved in filtering blood to produce urine. It consists of structures like the glomerulus, Bowman’s capsule, proximal tubule, Loop of Henle, distal tubule, and collecting duct.
Glomerulus: A network of capillaries in the nephron where filtration of blood occurs.
Bowman’s capsule: The part of the nephron that encases the glomerulus and receives the filtrate from blood.
Proximal tubule: The segment of the nephron where most of the selective reabsorption of water, nutrients, and ions takes place.
Loop of Henle: A part of the nephron that creates a concentration gradient in the kidney to help with water reabsorption.
Distal tubule: The portion of the nephron involved in fine-tuning the balance of ions and water in urine.
Collecting duct: The final portion of the nephron that collects urine and further regulates water and ion concentrations.
Glomerular filtration: The process by which blood is filtered in the glomerulus, allowing water, ions, and small molecules to pass into the nephron.
Selective reabsorption: The process by which useful substances, such as glucose and water, are reabsorbed back into the blood from the filtrate in the nephron.
Secretion: The process by which additional waste products are transported from the blood into the nephron for excretion.
Enzyme: A protein that acts as a catalyst to speed up chemical reactions in the body.
Active site: The region of an enzyme where the substrate binds and a chemical reaction is catalyzed.
Induced-fit model: A model of enzyme action where the enzyme changes shape slightly to accommodate the substrate.
Lock-and-key model: A model of enzyme action where the enzyme's active site and the substrate fit together like a key in a lock, without change in the enzyme's shape.
Enzyme activity: The rate at which an enzyme catalyzes a reaction, which can be influenced by temperature, pH, substrate concentration, and the presence of inhibitors.
Inhibitor: A substance that decreases or blocks the activity of an enzyme.
Topic 3: Cellular Energy, Gas Exchange, and Plant Physiology
Catabolism: The breakdown of complex molecules into simpler ones, releasing energy.
Anabolism: The synthesis of complex molecules from simpler ones, requiring energy.
ATP (Adenosine Triphosphate): A molecule that stores and transfers energy within cells. It is produced through catabolic reactions and used in anabolic reactions.
Aerobic respiration: A process of energy production in cells that requires oxygen, producing carbon dioxide, water, and ATP.
Anaerobic respiration: Energy production in cells that occurs without oxygen, resulting in less ATP production and the formation of byproducts like lactic acid (in animals) or ethanol and carbon dioxide (in plants and yeast).
Glycolysis: The first stage of cellular respiration where glucose is broken down into pyruvate, generating a small amount of ATP and NADH.
Krebs cycle: A series of chemical reactions that take place in the mitochondria, where acetyl-CoA is broken down to produce carbon dioxide, ATP, NADH, and FADH2.
Electron transport chain: The final stage of aerobic respiration where electrons are transferred through proteins in the mitochondrial membrane, generating a large amount of ATP.
Respiratory system: The system responsible for the exchange of gases (oxygen and carbon dioxide) between the body and the environment, primarily through the lungs.
Alveoli: Small air sacs in the lungs where gas exchange occurs between the air and blood.
Capillaries: The small blood vessels where the exchange of oxygen and carbon dioxide between blood and tissues happens.
Photosynthesis: The process by which plants and some other organisms convert light energy into chemical energy, producing glucose and oxygen as byproducts.
Light-dependent reactions: The first stage of photosynthesis where sunlight is used to produce ATP and NADPH, occurring in the thylakoid membranes of chloroplasts.
Light-independent reactions (Calvin cycle): The second stage of photosynthesis where ATP and NADPH are used to fix carbon dioxide into glucose, occurring in the stroma of chloroplasts.
Xylem: Vascular tissue in plants that transports water and minerals from the roots to the rest of the plant.
Phloem: Vascular tissue in plants that transports sugars and other organic nutrients from the leaves to the rest of the plant.
Stomata: Small openings in the epidermis of plant leaves that allow gas exchange and water vapor to exit.
Guard cells: Specialized cells surrounding the stomata that regulate their opening and closing to control gas exchange and water loss.
Transpiration: The process by which water is absorbed by plant roots, moves through the plant, and evaporates from the leaves, helping with nutrient and gas exchange.
Unit 2: Maintaining the Internal Environment
Subject Matter Topic 1: Homeostasis
Homeostasis: The process by which organisms maintain a stable internal environment despite external changes, ensuring optimal conditions for metabolic processes.
Negative Feedback: A mechanism in which a change in a physiological variable triggers a response that counteracts the initial fluctuation, returning the system to its set point. This process helps maintain homeostasis.
Nervous System: The network of nerve cells (neurons) and fibers that transmits electrical impulses throughout the body. It coordinates responses to stimuli.
Endocrine System: The system of glands that secrete hormones into the bloodstream, which regulate various physiological processes including metabolism, growth, and mood.
Stimulus-Response Model: A model of homeostasis where a stimulus (internal or external change) triggers a response that corrects or adapts to the change, maintaining stability in the body.
Sensory Receptors: Specialized cells that detect environmental changes and send signals to the brain. These include:
Chemoreceptors: Detect chemical stimuli such as changes in blood oxygen or pH levels.
Thermoreceptors: Detect temperature changes in the environment or body.
Mechanoreceptors: Detect mechanical changes, such as pressure or vibration.
Photoreceptors: Detect light, allowing organisms to see.
Nociceptors: Detect pain or harmful stimuli.
Nerve Cells (Neurons): Cells that transmit electrical impulses. Key components:
Dendrites: Extensions of the neuron that receive signals.
Soma (Cell Body): Contains the nucleus and other organelles.
Axon: The long, slender projection that transmits nerve impulses.
Myelin Sheath: Fatty layer that insulates axons, speeding up impulse transmission.
Nodes of Ranvier: Gaps in the myelin sheath that facilitate rapid signal transmission.
Axon Terminal: The end of the axon where neurotransmitters are released.
Synapse: The junction between two neurons or a neuron and another cell.
Neurons:
Sensory Neurons: Carry sensory information from receptors to the central nervous system.
Interneurons: Relay information within the central nervous system.
Motor Neurons: Transmit commands from the central nervous system to muscles or glands.
Action Potential: A rapid, temporary change in the electrical charge across the neuron's membrane, allowing the transmission of a nerve impulse.
Synaptic Transmission: The process by which an action potential in a neuron triggers the release of neurotransmitters across a synapse to transmit the signal to the next cell.
Neurotransmitters: Chemicals that transmit signals across synapses from one neuron to another or to a target cell (e.g., acetylcholine, dopamine).
Receptors: Proteins on or in target cells that bind to specific hormones or neurotransmitters to initiate a response in the cell.
Hormones: Chemical messengers secreted by endocrine glands into the bloodstream to regulate various body functions such as growth, metabolism, and mood.
Signal Transduction: The process by which a cell responds to a signal (e.g., a hormone) by converting the external signal into a functional change within the cell.
Receptor Binding: When a hormone or signaling molecule binds to its specific receptor on a target cell, initiating a response, such as altering cellular activity.
Feedback-Control Diagrams: Diagrams used to understand how homeostatic systems work by identifying the stimulus, receptor, control center, effector, and communication pathway.
Thermoregulation: The process by which an organism maintains its internal body temperature within a narrow range despite environmental changes.
Endotherms: Organisms that maintain a constant internal temperature through internal processes (e.g., humans).
Brown Adipose Tissue: Specialized fat tissue that helps with heat production.
Insulation: Features like fat or fur that help maintain body temperature by reducing heat loss.
Kleptothermy: A behavior in which one animal uses the heat of another animal to regulate its temperature.
Hibernation: A physiological state of reduced metabolic activity to conserve energy during cold conditions.
Aestivation: A state of dormancy in hot or dry conditions.
Torpor: A short-term, reduced metabolic rate to conserve energy.
Thermoregulatory Mechanisms in Humans:
Sweating: Evaporation of sweat from the skin surface that cools the body.
Shivering: Involuntary muscle contractions that generate heat.
Vasodilation: The widening of blood vessels near the skin surface to release heat.
Vasoconstriction: The narrowing of blood vessels to retain heat.
Osmoregulation: The process of maintaining the balance of water and electrolytes in the body.
Antidiuretic Hormone (ADH): A hormone that regulates water balance by controlling the amount of water reabsorbed by the kidneys.
Kidney: Organ responsible for filtering blood and maintaining water and electrolyte balance through processes like filtration, reabsorption, and secretion.
Stomata: Small pores in plant leaves that allow gas exchange (e.g., oxygen and carbon dioxide) and water vapor to exit.
Vacuoles: Membrane-bound organelles in plant cells that store water and other substances, helping with osmoregulation.
Cuticle: A waxy layer on plant leaves that helps prevent water loss.
Abscisic Acid: A plant hormone that plays a key role in water conservation, including closing stomata to reduce water loss.
Tolerance Limits: The range of environmental conditions that a species can endure before it experiences harm.
Kleptothermy: A behavioral strategy in which animals exploit the body heat of others.
Topic 2: Infectious Disease and Epidemiology
Infectious vs Non-Infectious Diseases
Infectious Disease: A disease caused by microorganisms (pathogens) such as bacteria, viruses, fungi, or parasites that can spread from person to person or through other vectors (e.g., air, water, animals).
Non-Infectious Disease: Diseases not caused by pathogens but by factors like genetics, environmental influences, or lifestyle choices (e.g., heart disease, cancer, diabetes).
Pathogens
Prions: Infectious agents composed of protein that can cause neurodegenerative diseases in animals and humans (e.g., mad cow disease).
Viruses: Non-living pathogens made of genetic material (DNA or RNA) encased in a protein coat that require a host cell to reproduce (e.g., influenza, HIV).
Bacteria: Single-celled microorganisms that can cause infections through the release of toxins or direct invasion of tissues (e.g., tuberculosis, streptococcus).
Fungi: Eukaryotic organisms that can be pathogenic, especially in immunocompromised individuals (e.g., athlete's foot, candida).
Protists: Single-celled eukaryotic organisms that can cause diseases like malaria (e.g., Plasmodium).
Parasites: Organisms that live in or on a host and benefit at the host's expense, often causing diseases (e.g., tapeworms, lice, malaria).
Pathogenesis
Adherence Factors: Structures like pili or fimbriae on pathogens that allow them to attach to host cells and tissues.
Invasion Factors: Enzymes or mechanisms used by pathogens to penetrate host defenses and invade tissues.
Capsules: Protective outer layers on some bacteria that prevent them from being engulfed by host immune cells.
Toxins: Harmful substances produced by pathogens (e.g., bacterial endotoxins and exotoxins) that damage host cells or tissues.
Immune System
Host Cell Recognition of Self vs Non-Self: The immune system can distinguish between body cells (self) and foreign cells (non-self) through molecules like MHC proteins.
Innate Immune Response: The body's first line of defense against pathogens, including:
Skin and Mucous Membranes: Physical barriers preventing pathogen entry.
Complement System: Proteins in the blood that help antibodies and phagocytes kill pathogens.
Adaptive Immune Response: A specific immune response involving recognition of antigens, including:
Humoral Response: Involves B lymphocytes that produce antibodies to neutralize pathogens.
Cell-Mediated Response: Involves T lymphocytes that destroy infected host cells.
Memory Cells: Long-lived cells that "remember" pathogens for faster response upon future exposure.
Prostaglandins: Lipid compounds that mediate inflammation, including vasodilation and pain sensation during infection.
Vasodilation: The widening of blood vessels to increase blood flow to an infected area.
Neutrophils: White blood cells that are the first responders to infection and engulf pathogens through phagocytosis.
Macrophages: Large immune cells that consume pathogens, present antigens, and secrete cytokines to activate other immune cells.
Natural Killer Cells: Immune cells that target and destroy virus-infected or tumor cells.
Immunity
Active Immunity: Immunity gained after exposure to an antigen, either through infection or vaccination.
Passive Immunity: Immunity conferred by receiving antibodies from another source, such as from mother to child or via antibody injections.
Naturally Acquired Passive Immunity: Transfer of antibodies from mother to infant (e.g., breast milk).
Artificially Acquired Passive Immunity: Transfer of antibodies through medical treatments like antivenom or monoclonal antibodies.
Infectious Disease Transmission
Modes of Disease Transmission:
Direct Contact: Physical transfer of pathogens (e.g., touching an infected person).
Contact with Body Fluids: Transmission through fluids like blood, saliva, or semen (e.g., HIV, hepatitis).
Contaminated Food or Water: Ingestion of pathogens through contaminated food or drinking water (e.g., cholera, norovirus).
Disease-Specific Vectors: Organisms (e.g., mosquitoes, ticks) that transmit diseases to humans (e.g., malaria, Lyme disease).
Disease Spread and Control
Factors Affecting Disease Spread:
Persistence of Pathogens: How long pathogens can survive in the environment or within a host.
Transmission Mechanism: How easily and through which means the pathogen spreads.
Immunity Proportion: The percentage of the population that is immune to the disease or has been vaccinated.
Mobility of Individuals: The ease with which people travel, contributing to the spread of diseases.
Control Measures:
Personal Hygiene: Practices like handwashing and using disinfectants to reduce pathogen spread.
Contact Tracing: Identifying and monitoring individuals who have come into contact with an infected person.
Quarantine: Isolating infected individuals to prevent the spread to others.
Long-term Immune Response Data
Epidemiological Data: Using data to track and predict the course of disease outbreaks, identify sources, and determine control strategies.
Innate Immune Response in Plants
Physical Defence Strategies: Structural features like thick cell walls, waxy cuticles, and leaf structures that prevent pathogen entry.
Chemical Defence Strategies: Production of toxins, enzymes, and plant defensins to deter or kill pathogens.
Scientific Inquiry
Antimicrobial Agents: Substances that kill or inhibit the growth of microorganisms (e.g., antibiotics, antiseptics).
Zones of Inhibition: Areas around an antimicrobial agent where microbial growth is prevented, measured to assess the effectiveness of the agent.
Vaccination and Immunization
Mass Vaccination Programs: Large-scale efforts to immunize populations against infectious diseases (e.g., smallpox, polio, influenza).
Vaccine Development: The process of creating vaccines to stimulate immune responses and prevent diseases.
First Nations' Knowledge
Bush Medicines: Traditional healing practices using local plants and natural substances, which have been used by First Nations peoples for centuries to prevent and treat infections.
