Introduction to Biology

• Biology scientifically explores life.
• This includes the structure, function, growth, origin, evolution, and distribution of living organisms.
• Cells are the basic unit of life.
• Genes are the unit of heredity.
• Evolution is the mechanism that propels creation and extinction of species.

Core Principles of Biology

• Cell theory states all living organisms are composed of one or more cells.
• The cell is the basic unit of structure, function, and organization in all organisms.
• All cells originate from pre-existing cells.
• Gene theory: Genes are the basic units of heredity composed of DNA.
• Genes provide the instructions for the structure and function of cells.
• Genes are passed from parents to offspring.
• Evolution is change in heritable characteristics of biological populations over generations.
• Evolutionary processes give rise to diversity at all levels of biological organization including species, individual organisms, and molecules.
• Homeostasis: All living organisms must maintain a stable internal environment, including temperature, pH, and substance concentrations.
• Thermodynamics: All living organisms require energy, obtained from the environment, and converted via metabolic processes.

Branches of Biology

• Biochemistry studies chemical substances and vital processes in living organisms.
• Botany is the scientific study of plants, including their physiology, structure, genetics, ecology, distribution, classification, and economic importance.
• Cell Biology studies of cell structure and function.
• Ecology studies the interactions between organisms and their environment.
• Evolutionary Biology studies the evolutionary processes shaping life's diversity on Earth.
• Genetics studies heredity and variation in organisms.
• Microbiology studies microorganisms like bacteria, viruses, fungi, and protozoa.
• Molecular Biology studies the molecular basis of life, including DNA, RNA, and proteins.
• Physiology studies functions and mechanisms within a living system.
• Zoology studies animals, including their physiology, structure, genetics, ecology, behavior, classification, and distribution.

Levels of Organization in Biology

• Molecules: Atoms combine to form molecules, such as DNA, RNA, and proteins.
• Cells: Molecules assemble into cells, the basic unit of life.
• Tissues: Similar cells group together to form tissues, such as muscle tissue, nerve tissue, and epithelial tissue.
• Organs: Different tissues combine to form organs, such as the heart, brain, and liver.
• Organ Systems: Organs work together to form organ systems, such as the circulatory system, nervous system, and digestive system.
• Organisms: Organ systems combine to form organisms, such as plants, animals, and bacteria.
• Populations: Groups of organisms of the same species living in the same area.
• Communities: Populations of different species living in the same area.
• Ecosystems: Communities of organisms and their physical environment.
• Biosphere: All of the ecosystems on Earth.

The Scientific Method in Biology

• Observation involves observing a phenomenon or identifying a problem.
• Hypothesis is formulating a testable explanation for the observation.
• Prediction is making a specific prediction based on the hypothesis.
• Experimentation involves designing/conducting an experiment to test the prediction.
• Analysis involves analyzing the data collected from the experiment.
• Conclusion involves determining whether the hypothesis is supported or refuted.

Key Biological Molecules

• Carbohydrates are a primary source of energy for cells.
• Lipids: Fats, oils, and waxes that store energy, insulate the body, and form cell membranes.
• Proteins are complex molecules that catalyze reactions, transport molecules, and provide structural support.
• Nucleic Acids: DNA and RNA carry genetic information.

Cell Structure and Function

• The Cell Membrane is the outer boundary that regulates the movement of substances.
• The Nucleus is the control center containing DNA.
• The Cytoplasm is the gel-like substance inside the cell containing organelles.
• Organelles are structures performing specific functions, like mitochondria (energy production), ribosomes (protein synthesis), and endoplasmic reticulum (protein/lipid synthesis).

Energy and Metabolism

• Photosynthesis is the process by which light energy is converted into glucose.
• Cellular Respiration is the process by which cells break down glucose to release energy as ATP.
• Enzymes: Proteins that catalyze biochemical reactions.
• Metabolism: The sum of all chemical reactions in a living organism.

Genetics and Heredity

• DNA carries genetic information.
• Genes are segments of DNA that code for specific traits.
• Chromosomes are structures made of DNA and proteins that contain genes.
• Cell Division includes mitosis (for growth and repair) and meiosis (for sexual reproduction).
• Inheritance is the passing of traits from parents to offspring.
• Mutations are changes in DNA that can lead to variation in traits.

Evolution and Biodiversity

• Natural Selection: Organisms with traits suited to their environment survive and reproduce more successfully.
• Adaptation is a trait that helps organisms survive and reproduce in their environment.
• Speciation is the process by which new species arise.
• Biodiversity: The variety of life on Earth, including genes, species, and ecosystems.

Ecology and Environment

• Populations are groups of same-species organisms in the same area.
• Communities are groups of different species in the same area interacting with each other.
• Ecosystems are communities of organisms and their physical environment.
• Biomes are large geographic areas with similar climates and ecosystems.
• Biosphere: All of the ecosystems on Earth.
• Environmental Issues are problems threatening the health of the environment, such as pollution, climate change, and deforestation.

Viruses

• Viruses are acellular entities with a nucleic acid core (DNA or RNA) surrounded by a protein coat called a capsid.
• They are obligate intracellular parasites, needing a host cell to replicate.
• Viruses infect various organisms, including bacteria, plants, and animals.
• Viral infections can cause diseases, from the common cold to AIDS.
• Virology is the study of viruses.

Biology is the scientific study of life, exploring structure, function, and evolution. Key principles include cell theory, stating all life comprises cells, and gene theory, highlighting genes as heredity units. Evolution drives species diversity and adaptation.