Biology Notes PDF
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These notes provide an overview of cell biology, including cell structure, division, and transport mechanisms. They also discuss sections on the circulatory, respiratory, and digestive systems in the human body. Suitable for high school biology.
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Biology Cell Biology Cell Structure: ○ Prokaryotic Cells: Characteristics: Simple structure, lack membrane-bound organelles. Examples: Bacteria and Archaea. ○ Eukaryotic Cells: Characteristics: Complex structure wit...
Biology Cell Biology Cell Structure: ○ Prokaryotic Cells: Characteristics: Simple structure, lack membrane-bound organelles. Examples: Bacteria and Archaea. ○ Eukaryotic Cells: Characteristics: Complex structure with membrane-bound organelles. Examples: Plant cells, animal cells, fungi, and protists. ○ Organelles: Nucleus: Contains DNA; controls cell activities. Mitochondria: Site of cellular respiration; produces ATP (energy). Chloroplasts: Found in plant cells; site of photosynthesis, converts solar energy into chemical energy (glucose). Endoplasmic Reticulum (ER): Rough ER: Studded with ribosomes; synthesizes proteins. Smooth ER: Lacks ribosomes; synthesizes lipids and detoxifies toxins. Golgi Apparatus: Modifies, sorts, and packages proteins for secretion or use within the cell. Lysosomes: Contain digestive enzymes to break down waste and cellular debris. Cell Division: ○ Mitosis: Purpose: Growth and repair; results in two identical daughter cells. Phases: Prophase: Chromatin condenses into visible chromosomes. Metaphase: Chromosomes align at the cell's equatorial plane. Anaphase: Sister chromatids are pulled apart to opposite poles. Telophase: Nuclear membranes reform; chromosomes de-condense. ○ Meiosis: Purpose: Producing gametes (sperm and egg); results in four genetically diverse daughter cells. Phases: Meiosis I: Homologous chromosomes separate (reduction division). Meiosis II: Similar to mitosis; sister chromatids separate. Transport Mechanisms: ○ Diffusion: Movement of molecules from an area of high concentration to low concentration; does not require energy (passive). ○ Osmosis: Specific case of diffusion involving water; occurs across a semi-permeable membrane. ○ Active Transport: Movement of molecules against their concentration gradient, requiring energy (ATP); examples include sodium-potassium pump. Human Body Systems Circulatory System: ○ Components: Heart: Muscular organ with four chambers (right atrium, right ventricle, left atrium, left ventricle); pumps blood throughout the body. Blood Vessels: Arteries: Carry oxygenated blood away from the heart (except pulmonary artery). Veins: Carry deoxygenated blood toward the heart (except pulmonary veins). Capillaries: Microscopic vessels where gas and nutrient exchange occurs. ○ Blood Composition: Red Blood Cells: Carry oxygen (hemoglobin). White Blood Cells: Part of the immune system. Platelets: Involved in blood clotting. Plasma: Liquid component that carries cells, nutrients, hormones, and waste. Respiratory System: ○ Components: Nasal Cavity: Filters, warms, and humidifies air. Trachea: Windpipe that conducts air to the lungs. Bronchi and Bronchioles: Branches that lead into the lungs; further divide into smaller airways. Alveoli: Tiny air sacs where gas exchange occurs; surrounded by capillaries. ○ Gas Exchange Process: Oxygen diffuses from alveoli into the blood, while carbon dioxide diffuses from blood into alveoli to be exhaled. Digestive System: ○ Organs: Mouth: Mechanical digestion (chewing) and chemical digestion (saliva). Esophagus: Muscular tube that transports food to the stomach via peristalsis. Stomach: Acidic environment (HCl) that breaks down food; enzymes aid in digestion. Small Intestine: Major site of nutrient absorption; lined with villi to increase surface area. Large Intestine: Absorbs water and forms waste (feces); includes the colon and rectum. ○ Digestive Enzymes: Amylase: Breaks down carbohydrates. Pepsin: Breaks down proteins in the stomach. Lipase: Breaks down fats. Ecology Ecosystems: ○ Definition: A biological community of interacting organisms and their physical environment. ○ Components: Biotic Factors: Living organisms (plants, animals, fungi). Abiotic Factors: Non-living elements (water, soil, climate). Food Chains and Webs: ○ Food Chain: Linear sequence of energy transfer (e.g., grass → grasshopper → frog → snake). ○ Food Web: Interconnected food chains showing complex feeding relationships. Biodiversity: ○ Definition: Variety of life forms within an ecosystem; includes genetic, species, and ecosystem diversity. ○ Importance: Ecosystem resilience, stability, and potential for new resources (medicinal). Chemistry Basic Chemistry Concepts Atoms and Molecules: ○ Atoms: Smallest unit of matter, consisting of a nucleus (protons and neutrons) surrounded by electrons. ○ Molecules: Formed when two or more atoms bond together (e.g., H₂O, CO₂). Periodic Table: ○ Structure: Organized by increasing atomic number; groups indicate similar chemical properties. ○ Trends: Atomic Radius: Decreases across a period; increases down a group. Electronegativity: Ability of an atom to attract electrons; increases across a period; decreases down a group. Chemical Reactions Types of Reactions: ○ Synthesis (Combination): A + B → AB. ○ Decomposition: AB → A + B. ○ Single Replacement: A + BC → AC + B. ○ Double Replacement: AB + CD → AD + CB. Balancing Chemical Equations: ○ Ensure that the number of atoms for each element is the same on both sides of the equation (conservation of mass). Acids and Bases Properties of Acids and Bases: ○ Acids: Sour taste, pH < 7, turn blue litmus paper red, produce H⁺ ions in solution. ○ Bases: Bitter taste, pH > 7, turn red litmus paper blue, produce OH⁻ ions in solution. pH Scale: ○ Ranges from 0 (strong acids) to 14 (strong bases), with 7 being neutral; each unit change represents a tenfold change in acidity/basicity. Physics Forces and Motion Newton’s Laws of Motion: ○ First Law (Law of Inertia): An object at rest remains at rest, and an object in motion remains in motion unless acted upon by an external force. ○ Second Law (F = ma): The acceleration of an object depends on the mass of the object and the amount of force applied. ○ Third Law: For every action, there is an equal and opposite reaction. Motion Concepts: ○ Speed: Distance traveled per unit time (s = d/t). ○ Velocity: Speed with a direction; includes displacement over time. ○ Acceleration: Change in velocity over time (a = Δv/Δt). Energy Types of Energy: ○ Kinetic Energy (KE): Energy of motion, calculated using KE = 1/2 mv², where m is mass and v is velocity. ○ Potential Energy (PE): Stored energy based on position, calculated using PE = mgh, where m is mass, g is gravitational acceleration, and h is height. Energy Transformation: Energy can change from one form to another (e.g., potential to kinetic energy in a falling object). Waves Types of Waves: ○ Mechanical Waves: Require a medium to travel (e.g., sound waves). ○ Electromagnetic Waves: Do not require a medium; travel at the speed of light (e.g., light waves, radio waves). Wave Properties: ○ Wavelength (λ): Distance between two consecutive crests or troughs. ○ Frequency (f): Number of waves that pass a point in one second (measured in Hertz). ○ Amplitude: Maximum displacement from the rest position. Mathematics Algebra Basic Operations: Mastery of addition, subtraction, multiplication, and division involving variables (e.g., simplifying expressions). Solving Equations: ○ Techniques for linear equations include isolating the variable, using inverse operations, and substituting values. Functions: ○ Defined as a relation where each input has one output; can be represented as equations, graphs, or tables. Geometry Shapes and Properties: ○ Triangles: Types (isosceles, equilateral, right); properties include the Pythagorean theorem. ○ Circles: Key formulas for circumference (C = 2πr) and area (A = πr²). Theorems: ○ Pythagorean Theorem: For right triangles, a² + b² = c², where c is the hypotenuse. ○ Properties of Angles: Complementary (sum to 90°) and supplementary (sum to 180°). Data Handling Statistics: ○ Mean: Average of a set of numbers; calculated by summing values and dividing by the number of values. ○Median: Middle value in an ordered list; if even, average the two middle numbers. ○ Mode: Most frequently occurring value in a dataset. Data Representation: ○ Bar Graphs: Used for categorical data; compares different groups. ○ Line Graphs: Used for continuous data; shows trends over time. ○ Pie Charts: Shows proportions of a whole; each slice represents a category's contribution to the total. Environmental Science Ecosystems and Biodiversity Ecosystem Components: ○ Producers: Organisms that produce their own food (e.g., plants via photosynthesis). ○ Consumers: Organisms that rely on others for food (herbivores, carnivores, omnivores). ○ Decomposers: Break down dead organic matter (fungi, bacteria). Threats to Biodiversity: ○ Habitat Loss: Deforestation, urbanization; disrupts ecosystems. ○ Pollution: Contaminates air, water, and soil; affects wildlife and human health. ○ Climate Change: Alters habitats and species distributions; leads to extinction of vulnerable species. Pollution Types of Pollution: ○ Air Pollution: Caused by emissions from vehicles and industries; effects include respiratory issues and global warming. ○ Water Pollution: Result of industrial waste, agricultural runoff, and plastics; impacts aquatic life and drinking water quality. Pollution Solutions: ○ Recycling: Reduces waste and conserves resources. ○ Waste Reduction: Minimizing single-use plastics and promoting reusable items. ○ Renewable Energy Adoption: Solar, wind, and hydroelectric energy sources to reduce fossil fuel dependence. Sustainability Resource Types: ○ Renewable Resources: Can be replenished naturally (e.g., solar, wind, geothermal). ○ Non-Renewable Resources: Finite resources that cannot be replenished (e.g., coal, oil, natural gas). Conservation Strategies: ○ Protecting Habitats: Establishing reserves and protected areas to conserve wildlife. ○ Sustainable Agriculture: Practices that minimize environmental impact while maintaining productivity (e.g., crop rotation, organic farming).