Cell Structure, Transport, and Division Vocabulary

Comprehensive vocabulary flashcards covering key terms from cell anatomy, transport mechanisms, and cell division.

Active transport

Energy-requiring movement of solutes from lower to higher concentration, usually using ATP.

Adenosine Triphosphate (ATP)

Primary energy carrier in cells; produced mainly by mitochondria.

Plasma membrane (Cell membrane)

Phospholipid bilayer that encloses the cell, controls passage of substances, and enables communication.

Selective permeability

Property of the plasma membrane that allows some substances to cross while restricting others.

Cytoplasm

Gel-like material between plasma membrane and nucleus; contains cytosol and organelles.

Organelle

Specialized intracellular structure that performs a specific metabolic function.

Nucleus

Cell’s control center housing DNA; surrounded by a double membrane with nuclear pores.

Nucleolus

Dense region in the nucleus where ribosomal subunits are assembled.

Chromatin

Uncondensed DNA–protein complex present in a non-dividing cell’s nucleus.

Chromosome

Condensed form of DNA visible during cell division; humans have 23 pairs (46).

Ribosome

Granule of rRNA and protein that serves as the site of protein synthesis.

Endoplasmic reticulum (ER)

Extensive membrane network continuous with the nuclear envelope.

Rough ER

ER studded with ribosomes; synthesizes proteins for membranes or secretion.

Smooth ER

ER lacking ribosomes; synthesizes lipids, stores Ca²⁺, and detoxifies chemicals.

Golgi apparatus

Stacks of flattened sacs that modify, sort, and package proteins and lipids for export or delivery.

Secretory vesicle

Membrane sac produced by the Golgi that releases its contents via exocytosis.

Lysosome

Vesicle containing digestive enzymes that break down ingested material and worn-out organelles.

Peroxisome

Organelle with enzymes that degrade fatty acids and detoxify hydrogen peroxide.

Mitochondrion

Bean-shaped organelle that performs aerobic respiration and generates most cellular ATP.

Cristae

Infoldings of the inner mitochondrial membrane where ATP-producing reactions occur.

Mitochondrial matrix

Fluid inside mitochondria containing enzymes, DNA, and ribosomes.

Cytoskeleton

Network of protein filaments giving structural support, movement, and organelle positioning.

Microfilaments

Thin actin strands providing mechanical support and enabling cell motility.

Intermediate filaments

Medium-sized filaments that stabilize organelle position and connect cells.

Microtubules

Hollow protein tubes that determine cell shape and form cilia, flagella, and spindle fibers.

Centrioles

Cylindrical structures of microtubule triplets that aid chromosome movement during mitosis.

Centrosome

Region near nucleus containing a pair of centrioles and pericentriolar material; organizes spindle fibers.

Cilia

Numerous short hair-like projections that move fluid or mucus across a cell’s surface.

Flagella

Long whip-like projection (e.g., on sperm) that propels the cell.

Microvilli

Minute plasma-membrane folds that greatly increase surface area for absorption.

Diffusion

Passive movement of particles from higher to lower concentration.

Concentration gradient

Difference in solute concentration between two regions.

Facilitated diffusion

Passive carrier-mediated transport of a substance down its concentration gradient through a membrane protein.

Osmosis

Diffusion of water across a selectively permeable membrane toward higher solute concentration.

Osmotic pressure

Force required to prevent water movement by osmosis; reflects a solution’s tendency to draw water.

Filtration

Movement of water and solutes through a membrane driven by hydrostatic pressure.

Hydrostatic pressure

Physical pressure exerted by a fluid on its container.

Isotonic solution

Extracellular fluid with solute concentration equal to the cell; no net water movement.

Hypotonic solution

Solution with lower solute concentration than the cell, causing water to enter the cell.

Hypertonic solution

Solution with higher solute concentration than the cell, drawing water out of the cell.

Carrier-mediated transport

Movement of molecules across a membrane via specific protein carriers.

Sodium–potassium pump

Primary active transporter that moves 3 Na⁺ out and 2 K⁺ into cells per ATP.

Secondary active transport

Transport that uses the energy of one solute’s gradient (often Na⁺) to drive another’s movement.

Endocytosis

Vesicular process that brings substances into a cell by membrane infolding.

Phagocytosis

“Cell eating” of large particles or microbes via endocytosis.

Pinocytosis

Nonspecific uptake of extracellular fluid (“cell drinking”) by small vesicles.

Receptor-mediated endocytosis

Selective uptake of molecules after they bind plasma-membrane receptors.

Exocytosis

Vesicular release of substances from a cell to the extracellular space.

Mitosis

Somatic cell division producing two genetically identical diploid daughter cells.

Interphase

Portion of the cell cycle with G₁, S, and G₂ phases where the cell grows and replicates DNA.

Prophase

First mitotic stage: chromatin condenses, spindle forms, nuclear envelope dissolves.

Metaphase

Mitotic stage where chromosomes line up along the cell’s equator.

Anaphase

Mitotic stage in which sister chromatids separate and move to opposite poles.

Telophase

Final mitotic stage: chromosomes decondense, new nuclei form, and cytokinesis completes.

Diploid

Condition of having two sets of chromosomes (2n); characteristic of somatic cells.

Meiosis

Cell division in gametes yielding four haploid cells through two successive divisions.

Tetrad

Pair of homologous chromosomes aligned together during prophase I of meiosis.

Crossing over

Exchange of DNA segments between homologous chromosomes in meiosis, increasing genetic variation.

Haploid

Having a single set of chromosomes (n); characteristic of sperm and ova.

Gametes

Reproductive cells (sperm or egg) produced by meiosis, each carrying half the genetic material.