Overview of Biology

Study of life and living organisms
Encompasses various fields including genetics, ecology, evolution, and cellular biology

Cell Theory
- All living organisms are composed of cells
- The cell is the basic unit of life
- All cells arise from pre-existing cells
Genetics
- Study of heredity and variation in organisms
- DNA: the molecule that carries genetic information
- Genes: segments of DNA that code for proteins
Evolution
- Process by which species change over time through natural selection
- Charles Darwin's theory of evolution by natural selection
- Common descent: all life shares a common ancestor
Ecology
- Study of interactions between organisms and their environment
- Ecosystems: communities of living organisms and their physical environments
- Biomes: large areas characterized by climate, flora, and fauna
Homeostasis
- Maintenance of a stable internal environment in organisms
- Involves feedback mechanisms (positive and negative)
Metabolism
- Sum of all chemical reactions in a living organism
- Catabolism: breaking down molecules for energy
- Anabolism: synthesizing compounds for growth and repair

Proteins: Made of amino acids; perform various functions (enzymes, structural support)
Carbohydrates: Sugars and starches; primary source of energy
Lipids: Fats and oils; long-term energy storage, cell membranes
Nucleic Acids: DNA and RNA; store and transmit genetic information

Photosynthesis: Conversion of light energy into chemical energy by plants
Cell Respiration: Process of breaking down glucose to produce energy (ATP)
Protein Synthesis: Process where cells build proteins based on genetic instructions (transcription and translation)

Biology is the scientific study of life and encompasses various fields such as genetics, ecology, evolution, and cellular biology.

Cell Theory
- Asserts that all living organisms consist of cells, making cells the fundamental unit of life.
- States that all cells originate from pre-existing cells.
Genetics
- Focuses on heredity and variations among organisms.
- DNA is the key molecule carrying genetic information, with genes being specific segments that code for proteins.
Evolution
- Describes the gradual changes in species through the mechanism of natural selection.
- Charles Darwin proposed the theory that emphasizes common descent where all life is derived from a shared ancestor.
Ecology
- Analyzes the relationships between organisms and their environments.
- Ecosystems consist of living organisms interacting within their physical surroundings, while biomes represent large areas defined by climate and living organisms.
Homeostasis
- Refers to the processes that maintain a stable internal environment in organisms through feedback mechanisms, both positive and negative.
Metabolism
- Represents the totality of chemical reactions in a living organism.
- Categorized into catabolism (energy-releasing breakdown of molecules) and anabolism (energy-consuming synthesis of compounds for growth).

Proteins: Composed of amino acids, crucial for various functions including enzymes and structural support.
Carbohydrates: Encompass sugars and starches, serving as the primary energy source.
Lipids: Include fats and oils, vital for long-term energy storage and forming cell membranes.
Nucleic Acids: DNA and RNA are responsible for storing and transmitting genetic information.

Photosynthesis: The process by which plants transform light energy into chemical energy.
Cell Respiration: Involves breaking down glucose to release energy in the form of ATP.
Protein Synthesis: The method by which cells construct proteins following genetic instructions, involving transcription and translation.

Domains: Three primary groups include Bacteria, Archaea, and Eukarya.
Kingdoms: Major classifications include Animalia, Plantae, Fungi, and Protista, among others.
Taxonomy: The scientific discipline dedicated to naming and categorizing organisms.

Biodiversity is increasingly threatened by habitat destruction, pollution, and climate change.
Emphasizes the necessity of conservation and sustainable practices to protect ecosystems.
Biotechnology and genetic engineering play significant roles in advancing medicine and agriculture.