Cell Structure and Function

Cell Structure and Function

• Cells are the basic units of life, exhibiting a complex internal organization
• Prokaryotic cells (bacteria and archaea) lack a nucleus and membrane-bound organelles
• Eukaryotic cells (plants, animals, fungi, protists) possess a nucleus and various organelles
• Cell membrane regulates the passage of substances in and out of the cell
• Cytoplasm is the gel-like substance within the cell, containing organelles
• Nucleus houses the cell's genetic material (DNA)
• Endoplasmic reticulum (ER) is involved in protein and lipid synthesis
• Ribosomes are the sites of protein synthesis
• Golgi apparatus processes and packages proteins
• Mitochondria are the powerhouses of the cell, involved in energy production (cellular respiration)
• Chloroplasts (plant cells) capture light energy for photosynthesis
• Lysosomes contain enzymes that break down cellular waste
• Vacuoles store water, nutrients, and waste products
• Cytoskeleton provides structural support and facilitates cell movement

Biological Molecules

• Carbohydrates are composed of carbon, hydrogen, and oxygen, providing energy
• Lipids (fats, oils, steroids) include fatty acids and are important for energy storage and structure
• Proteins are chains of amino acids, performing a wide array of functions
• Nucleic acids (DNA and RNA) store and transmit genetic information

Cell Metabolism

• Metabolism refers to all chemical reactions within a cell
• Catabolism breaks down complex molecules into simpler ones
• Anabolism builds complex molecules from simpler ones
• Cellular Respiration is a process where glucose is broken down to produce ATP
• Photosynthesis is the process where plants use light to convert carbon dioxide and water into glucose

Cell Growth and Division

• Mitosis is the process of cell division in somatic (body) cells
• Meiosis is the process of cell division in germ (reproductive) cells
• Cell cycle involves phases like interphase, mitosis, and cytokinesis
• DNA replication is crucial for cell division
• Cancer is uncontrolled cell growth and division

Genetics

• Genes are segments of DNA that code for specific proteins
• DNA carries the genetic information
• RNA is involved in protein synthesis
• Genes are inherited from parents to offspring
• Mutations are changes in the DNA sequence
• Chromosomes are structures that contain DNA

Ecology

• Ecology is the study of interactions between organisms and their environment
• Ecosystems include living (biotic) and non-living (abiotic) components
• Species interactions (predation, competition, symbiosis) influence populations
• Nutrient cycles (carbon, nitrogen, water) are crucial to ecosystem health
• Biodiversity is the variety of life in an area
• Biomes are large geographical areas with distinct climates and organisms

Evolution

• Evolution is the change in heritable characteristics of biological populations over successive generations
• Natural selection is the process where traits that enhance survival and reproduction become more common in a population
• Adaptation is the process of becoming better suited to an environment
• Common ancestry is the shared evolutionary history of organisms
• Speciation is the formation of new species

Classification of Organisms

• Classification systems organize organisms based on shared characteristics
• Taxonomy is the science of naming and classifying organisms
• Linnaean system uses hierarchical categories (Kingdom, Phylum, Class, Order, Family, Genus, Species)
• Modern classification uses evolutionary relationships (phylogenies)