Introduction to Biology

Biology

• Biology is the study of life and living organisms, including their structure, function, growth, origin, evolution, and distribution.
• Key branches include:
  • Cell biology: Study of cells, their components, and their functions.
  • Genetics: Study of genes, heredity, and variation in organisms.
  • Ecology: Study of interactions between organisms and their environment.
  • Evolutionary biology: Study of the processes that have led to the diversity of life on Earth.
  • Physiology: Study of the functions of living organisms and their parts.
• Fundamental concepts:
  • Cell theory: All living things are composed of cells; cells are the basic unit of life; new cells are created from existing cells.
  • Homeostasis: Maintaining a stable internal environment despite external changes.
  • Metabolism: Chemical reactions that occur in living organisms to sustain life.
  • Energy flow: Transfer of energy within an ecosystem.
• Levels of organization in biological systems:
  • Atoms → molecules → macromolecules → organelles → cells → tissues → organs → organ systems → organism → population → community → ecosystem → biosphere.
• Classification of life forms:
  • Organisms are classified into domains (Bacteria, Archaea, Eukarya) and kingdoms (e.g., Animalia, Plantae, Fungi).
• Processes within organisms:
  • Respiration, photosynthesis, reproduction, and movement are essential for survival and reproduction within all organisms.

Chemistry

• Chemistry is the study of matter, its properties, its composition, and how it changes.
• Matter is anything that has mass and takes up space.
• Key concepts:
  • Elements: Pure substances made of only one type of atom.
  • Compounds: Substances formed by the chemical combination of two or more different elements.
  • Atoms: The basic building blocks of matter.
  • Molecules: Groups of two or more atoms held together by chemical bonds.
  • Chemical bonds: Forces that hold atoms together in molecules.
• Types of chemical reactions:
  • Synthesis: Two or more substances combine to form a more complex substance.
  • Decomposition: A complex substance breaks down into simpler substances.
  • Single replacement: One element replaces another in a compound.
  • Double replacement: Two elements in different compounds exchange places.
• States of matter:
  • Solid, liquid, and gas.
• Periodic table:
  • Organized arrangement of all known elements.
• Atomic structure:
  • Nucleus (protons and neutrons); electron shell(electrons).
• Stoichiometry:
  • Quantitative relations between reactants and products in chemical reactions.
• Chemical bonding:
  • Ionic, covalent, metallic.
• Acid-base chemistry:
  • Acidic and basic properties of substances, measured by pH.
• Thermodynamics:
  • Study of energy changes in chemical reactions.

Physics

• Physics is the study of matter, energy, and their interactions.
• Key areas:
  • Mechanics: Study of motion and forces.
  • Thermodynamics: Study of heat and temperature.
  • Electromagnetism: Study of electric and magnetic fields.
  • Optics: Study of light.
  • Quantum mechanics: Study of the behavior of matter and energy at the atomic level.
  • Relativity: Study of space, time, gravity, and the universe.
• Fundamental principles:
  • Newton's laws of motion: Describe the relationship between forces and motion.
  • Newton's law of universal gravitation: Explains the force of attraction between any two masses.
  • Conservation of energy: Energy cannot be created or destroyed, only transformed.
  • Conservation of momentum: The total momentum of a system remains constant if no external forces act on it.
• Important concepts:
  • Vectors and scalars: Quantities with magnitude and direction (vectors) versus quantities with only magnitude (scalars).
  • Kinematics: Study of motion without considering the forces causing it.
  • Dynamics: Study of motion and the forces causing it.
  • Energy: The ability to do work.
  • Work: Force applied over a distance.
  • Power: Rate at which work is done.
• Units and measurements:
  • SI units (International System of Units) are used for measurements in physics. Such as meters (m) for length, kilograms (kg) for mass, seconds (s) for time, and joules (J) for energy.
• Waves:
  • Mechanical and electromagnetic waves transmit energy through a medium or space.
• Gravity:
  • Force of attraction between any two masses.