Cell Biology

Cell biology is unit economics at the most fundamental level. Every term in this category describes what happens inside the basic unit of life—the decisions, trade-offs, and mechanisms that determine whether a cell survives, divides, or dies. It's the startup stage of biology. The core insight of cell biology is that cells are not simple. A single cell runs thousands of simultaneous reactions, makes complex decisions about resource allocation, and contains more sophisticated machinery than any factory humans have built. The vocabulary here demolishes any assumption that 'basic' means 'simple.' Cell biology vocabulary helps you think about unit-level operations. Mitosis is replication—creating a copy of yourself. Apoptosis is programmed death—sometimes the best thing a unit can do is die. The cell cycle is a regulatory checkpoint—ensuring conditions are right before committing to major decisions. These map directly to organizational dynamics. The terms here reveal why scaling isn't just 'more cells.' Cells coordinate through signaling, differentiate into specialized types, and sometimes sacrifice themselves for the organism's benefit. The transition from single-celled to multicellular life required solving governance problems that organizations still struggle with. After exploring this category, you'll understand that the unit level is where strategy becomes real—and that even the simplest units are more sophisticated than they appear.

Active Transport The movement of molecules across a cell membrane against their concentration gradient, requiring energy (typically ATP).... Apoptosis Programmed cell death, a controlled process where cells systematically dismantle themselves when damaged, infected, or n... Autophagy The cellular process of degrading and recycling damaged or unnecessary components. Literally 'self-eating,' autophagy cl... Bilayer A two-layered structure, particularly the phospholipid bilayer that forms cell membranes. Hydrophilic heads face outward... Checkpoint (Cell Cycle) Control points in the cell cycle where the cell verifies that conditions are correct before proceeding. Checkpoints prev... Chemotaxis Directed movement of an organism or cell in response to chemical gradients—toward attractants (positive chemotaxis) or a... Contact Inhibition The phenomenon where normal cells stop dividing when they contact neighboring cells. A crucial mechanism preventing unco... Cytoplasm The gel-like substance filling cells between the nucleus and cell membrane. Contains organelles, enzymes, and the cytosk... Endoplasmic Reticulum A network of membranes within cells that synthesizes, processes, and transports proteins and lipids. The rough ER (with... Endosymbiosis A symbiotic relationship where one organism lives inside the cells of another. The theory that mitochondria and chloropl... Eukaryote Complex cells containing a nucleus and specialized organelles—the result of ancient mergers that created entirely new ca... Flagellum A whip-like appendage that enables cell movement. Bacterial flagella rotate like propellers at up to 1,000 RPM; eukaryot... Growth Factor Signaling proteins that stimulate cell growth, proliferation, and differentiation. Growth factors bind to receptors on c... Meiosis A type of cell division that produces gametes (sex cells) with half the normal chromosome number. Unlike mitosis, meiosi... Membrane A thin, flexible barrier that surrounds cells and organelles, controlling what enters and exits. Composed primarily of a... Mitochondria Membrane-bound organelles in eukaryotic cells that generate most of the cell's ATP through cellular respiration. Often c... Mitosis The process of cell division that produces two genetically identical daughter cells from a single parent cell. The mecha... mTOR (Mechanistic Target of Rapamycin) A protein kinase that acts as a central regulator of cell growth, proliferation, and survival. mTOR integrates signals a... Necrosis Uncontrolled cell death caused by external factors like injury, infection, or lack of blood supply. Unlike apoptosis (pr... Nucleus The membrane-bound organelle in eukaryotic cells that contains the chromosomes and controls cell activities. The nucleus... Prokaryote Single-celled organisms lacking a membrane-bound nucleus and other membrane-bound organelles. Includes bacteria and arch... Receptor A protein molecule that receives and responds to specific signals, typically located on cell surfaces or inside cells. R... Ribosome Cellular structures that synthesize proteins by reading genetic instructions from messenger RNA. The protein factories o... Sirtuins A family of NAD⁺-dependent enzymes that regulate cellular health, stress resistance, and longevity. Sirtuins are activat... Vesicle A small membrane-bound sac that transports materials within cells or between cells and their environment. Vesicles move...