Fundamentals of Biology

• Biology is the scientific study of life
• It explores the structure, function, growth, origin, evolution, distribution, and taxonomy of living organisms

Core Principles of Biology

• Cell theory: All living organisms are composed of cells, and cells are the basic units of structure and function in living organisms
• Gene theory: Traits are inherited through genes, which are specific sequences of DNA that code for proteins
• Evolution: Life evolves over time through processes like natural selection, leading to the diversity of organisms
• Homeostasis: Living organisms maintain a stable internal environment despite changes in their external environment
• Thermodynamics: Life depends on the flow of energy, which is governed by the laws of thermodynamics

Levels of Biological Organization

• Molecules: Atoms combine to form molecules, such as water, proteins, carbohydrates, and lipids
• Cells: Molecules are organized into cells, the basic unit of life
• Tissues: Similar cells performing a specific function are organized into tissues
• Organs: Different tissues combine to form organs, such as the heart, lungs, and brain
• Organ systems: Organs work together to form organ systems, such as the digestive system, respiratory system, and circulatory system
• Organisms: Organ systems function together to form a complete organism
• Populations: Groups of the same species living in the same area
• Communities: Populations of different species living and interacting in the same area
• Ecosystems: Communities interacting with their physical environment
• Biosphere: All ecosystems on Earth combined

Chemistry of Life

• Water: Essential for life due to its properties as a solvent, its high heat capacity, and its role in many biochemical reactions
• Carbon: Forms the backbone of organic molecules, allowing for a diversity of complex structures
• Carbohydrates: Provide energy and structural support (e.g., sugars, starches, cellulose)
• Lipids: Include fats, oils, and phospholipids; used for energy storage, insulation, and cell membrane structure
• Proteins: Perform a wide range of functions, including catalysis (enzymes), transport, structure, and defense
• Nucleic acids: Store and transmit genetic information (DNA and RNA)

Cell Structure and Function

• Prokaryotic cells: Simple cells lacking a nucleus and other membrane-bound organelles (e.g., bacteria and archaea)
• Eukaryotic cells: Complex cells with a nucleus and other membrane-bound organelles (e.g., plant, animal, fungi, and protist cells)
• Nucleus: Contains the cell's DNA and controls cell activities
• Ribosomes: Synthesize proteins
• Endoplasmic reticulum (ER): Involved in protein and lipid synthesis
• Golgi apparatus: Modifies, sorts, and packages proteins and lipids
• Mitochondria: Generate energy (ATP) through cellular respiration
• Chloroplasts: Found in plant cells; perform photosynthesis
• Cell membrane: Regulates the movement of substances into and out of the cell
• Cell wall: Provides structural support and protection (present in plant, bacteria, fungi and algae)
• Cytoskeleton: Provides structural support and facilitates cell movement

Genetics

• DNA: Deoxyribonucleic acid; carries genetic information in the form of genes
• RNA: Ribonucleic acid; involved in protein synthesis and gene regulation
• Genes: Specific sequences of DNA that code for proteins or RNA molecules
• Chromosomes: Structures made of DNA and proteins that carry genes
• Replication: The process of copying DNA
• Transcription: The process of synthesizing RNA from a DNA template
• Translation: The process of synthesizing proteins from an RNA template
• Mutations: Changes in the DNA sequence that can lead to variations in traits
• Mendelian genetics: Principles of inheritance based on the work of Gregor Mendel

Evolution

• Natural selection: The process by which organisms with traits better suited to their environment survive and reproduce at a higher rate
• Adaptation: Traits that enhance an organism's survival and reproduction in a specific environment
• Genetic variation: Differences in genes among individuals in a population
• Speciation: The process by which new species arise
• Evidence for evolution: Fossil record, comparative anatomy, embryology, biogeography, and molecular biology

Ecology

• Populations: Groups of individuals of the same species living in the same area
• Communities: Interacting populations of different species in the same area
• Ecosystems: Communities interacting with their physical environment
• Biomes: Major regional or global biotic communities, such as forests, grasslands, and deserts
• Population ecology: Studies the size, density, distribution, and dynamics of populations
• Community ecology: Studies the interactions between different species in a community
• Ecosystem ecology: Studies the flow of energy and cycling of nutrients in ecosystems
• Biodiversity: The variety of life in an ecosystem or on Earth
• Conservation biology: The study and protection of biodiversity

Plant Biology

• Photosynthesis: The process by which plants convert light energy into chemical energy in the form of glucose
• Plant structure: Roots, stems, leaves, flowers, fruits, and seeds
• Plant tissues: Epidermal, vascular, and ground tissues
• Plant reproduction: Sexual and asexual reproduction
• Plant hormones: Regulate plant growth and development

Animal Biology

• Animal structure: Cells, tissues, organs, and organ systems
• Animal physiology: The study of how animal bodies function
• Animal behavior: The study of how animals interact with their environment and each other
• Animal development: The processes by which animals grow and develop from embryos to adults
• Animal classification: Grouping animals based on shared characteristics and evolutionary relationships

Microbiology

• Bacteria: Single-celled prokaryotic organisms
• Viruses: Non-cellular entities that require a host cell to replicate
• Fungi: Eukaryotic organisms that obtain nutrients by absorption
• Protists: Diverse group of eukaryotic microorganisms
• Microbial ecology: The study of the interactions between microorganisms and their environment
• Medical microbiology: The study of microorganisms that cause disease

Biotechnology

• Genetic engineering: Modifying the genetic material of organisms to produce desired traits
• Cloning: Creating genetically identical copies of organisms
• Recombinant DNA technology: Combining DNA from different sources
• Biotechnology applications: Medicine, agriculture, industry, and environmental science

Explore the core principles of biology, including cell theory, gene theory, evolution, homeostasis and thermodynamics. Learn about the levels of biological organization from molecules to ecosystems. Biology is the scientific study of life.