Biological Molecules and Cellular Structure

Biological Molecules

• Biological molecules are the fundamental components of all living organisms.
• Four major classes: carbohydrates, lipids, proteins, and nucleic acids.
• Carbohydrates: Composed of carbon, hydrogen, and oxygen. Function in energy storage and structural support. Examples include glucose, starch, and cellulose.
• Lipids: Hydrophobic molecules, primarily composed of carbon and hydrogen. Crucial for energy storage, insulation, and hormone production. Examples include fats, oils, and phospholipids.
• Proteins: Complex molecules built from amino acids. Perform diverse functions like catalysis, transport, and structural support. Examples include enzymes, antibodies, and hormones.
• Nucleic acids: Store and transmit genetic information. Composed of nucleotides. DNA and RNA are crucial examples.

Cellular Structure

• Cells are the basic units of life.
• Prokaryotic cells: Lack a nucleus and membrane-bound organelles. Common in bacteria and archaea.
• Eukaryotic cells: Contain a nucleus and membrane-bound organelles. Found in plants, animals, fungi, and protists.
• Organelles: Specialized structures within cells performing specific functions. Examples include mitochondria (energy production), ribosomes (protein synthesis), and endoplasmic reticulum (protein and lipid synthesis).
• Cell membranes: Regulate the passage of substances into and out of the cell. Made of a phospholipid bilayer.

Cell Processes

• Metabolism: Sum of all chemical reactions in a cell. Includes catabolism (breaking down molecules) and anabolism (building up molecules).
• Cellular respiration: Process of breaking down glucose to release energy in the form of ATP. Occurs in mitochondria.
• Photosynthesis: Process used by plants and other organisms to convert light energy into chemical energy (glucose). Takes place in chloroplasts.
• Cell division: Process by which cells reproduce. Includes mitosis (somatic cells) and meiosis (sex cells).
• DNA Replication: A crucial process where DNA makes a copy of itself during cell division.
• Protein Synthesis: The process of building proteins from amino acids based on instructions encoded in DNA. Involves transcription (DNA to RNA) and translation (RNA to protein).

Genetics

• Heredity: Passing of traits from parents to offspring.
• Genes: Segments of DNA that code for specific traits.
• Chromosomes: Structures containing DNA and proteins that package genes.
• Genotype: An organism's genetic makeup.
• Phenotype: An organism's observable characteristics.
• Mendelian genetics: Fundamental principles of inheritance discovered by Gregor Mendel. Includes concepts of dominant and recessive alleles.

Ecology

• Ecology: The study of the relationships between organisms and their environment.
• Ecosystems: Communities of organisms interacting with each other and their physical environment.
• Biomes: Large-scale communities characterized by specific climate and vegetation. Examples include forests, grasslands, and deserts.
• Food webs: Interconnected food chains showing energy flow within an ecosystem.
• Population dynamics: Study of how populations change over time. Factors like birth rate, death rate, immigration, and emigration influence population sizes.

Evolution

• Evolution: The process of change in heritable characteristics of biological populations over successive generations.
• Natural selection: The process where organisms with traits better suited to their environment are more likely to survive and reproduce.
• Adaptation: A trait that increases an organism's survival and reproduction in a particular environment.
• Speciation: The process by which new species arise.
• Common ancestry: The shared evolutionary history of different groups of organisms.

Classification

• Taxonomy: The science of classifying and naming organisms.
• Hierarchical classification system: Organisms are grouped into increasingly inclusive categories, from species to domain.
• Binomial nomenclature: A system for naming species using two names, genus and species.
• Phylogeny: The evolutionary history of a group of organisms.
• Phylogenetic trees: Diagrams that show evolutionary relationships.