Introduction to Cell Biology

• Biology is the scientific study of life, examining the structure, function, growth, origin, evolution, distribution, and taxonomy of living organisms
• Biology includes disciplines ranging from molecular biology to ecology
• Central themes are cell theory, gene theory, homeostasis, evolution, and energy

Cell Biology

• Cell biology explores cell structure, function, and behavior
• The cell is the basic unit of life
• Key areas: cell structure (organelles), cell function (metabolism, signaling), cell growth and division, and cell differentiation
• Eukaryotic cells possess a nucleus and membrane-bound organelles, unlike prokaryotic cells (bacteria and archaea)
• The plasma membrane regulates substance movement into and out of cells
• Organelles like mitochondria (energy production) and endoplasmic reticulum (protein synthesis and lipid metabolism) perform specific functions
• Cell signaling involves communication between cells, which regulates a variety of processes
• Cell division includes mitosis (for growth and repair) and meiosis (for sexual reproduction)

Ecology

• Ecology studies the interactions between organisms and their environment
• It examines how organisms interact with each other, as well as their physical and chemical environment
• Key concepts: populations, communities, ecosystems, and the biosphere
• Populations are groups of the same species in a particular area
• Communities consist of different species populations interacting in a specific area
• Ecosystems encompass an environment's biotic (living organisms) and abiotic (non-living) components
• The biosphere represents the global sum of all ecosystems
• Energy flow and nutrient cycling are crucial ecosystem processes
• Food chains and webs depict the movement of energy/nutrients through organisms
• Ecological interactions include competition, predation, mutualism, and parasitism
• Climate (temperature and precipitation) greatly influences ecosystem distribution
• Conservation biology is centered on protecting and managing biodiversity

Genetics

• Genetics is the study of heredity and variation in living organisms
• Explores how traits are passed from parents to offspring and how genetic information is organized/regulated
• Key components: genes, chromosomes, DNA, RNA, and the genetic code
• Genes are units of heredity with instructions for building proteins
• Chromosomes carry genes and are composed of DNA
• DNA (deoxyribonucleic acid) is the molecule containing genetic information, structured as a double helix
• RNA (ribonucleic acid) has multiple roles in gene expression
• The genetic code translates the nucleotide sequence of DNA into the amino acid sequence of proteins
• Gene expression involves transcription (DNA to RNA) and translation (RNA to protein)
• Mutations are changes in DNA sequence that can lead to variation
• Mendelian genetics describes basic inheritance principles, including segregation and independent assortment
• Population genetics studies genetic variation within and among populations

Evolution

• Evolution is how populations of organisms change over time
• Driven by natural selection, genetic drift, mutation, and gene flow
• Natural selection favors traits that improve survival and reproduction
• Genetic drift is the random change in allele frequencies in a population
• Mutation introduces new genetic variation into populations
• Gene flow is the movement of genes between populations
• Evidence for evolution comes from fossils, comparative anatomy, embryology, and molecular biology
• Speciation is the process by which new species arise
• Phylogenetic trees show the evolutionary relationships between different species
• Adaptation allows organisms to be better suited to their environment
• Macroevolution involves large-scale evolutionary changes, like the origin of new organism groups

Physiology

• Physiology studies the functions/mechanisms of living organisms and their parts
• Explores how organisms maintain homeostasis and respond to environmental changes
• Key areas: organ systems, cellular processes, and regulatory mechanisms
• Organ systems like circulatory, respiratory, digestive, and nervous systems perform specific bodily functions
• Cellular physiology focuses on processes within cells, including membrane transport, energy metabolism, and cell signaling
• Regulatory mechanisms such as hormones and neurotransmitters, coordinate and control physiological processes
• Homeostasis maintains a stable internal environment
• Feedback loops (negative and positive) regulate physiological processes
• Exercise physiology studies the effects of physical activity on the body
• Environmental physiology examines how organisms adapt to different environmental conditions