Cell Structure, Function, and Transport – Vocabulary Flashcards

A comprehensive set of English vocabulary flashcards covering key terms related to cell structure, organelles, extracellular components, membrane composition, and mechanisms of molecular transport as presented in the lecture notes.

Cell

The basic structural and functional unit of all living organisms.

Robert Hooke

English scientist who coined the term “cell” after observing cork cells in 1665.

Prokaryotic cell

Cell lacking a true nucleus and membrane-bound organelles; DNA is located in a nucleoid.

Eukaryotic cell

Cell possessing a membrane-bound nucleus and numerous membrane-bound organelles.

Nucleoid

Region in prokaryotes where the circular DNA chromosome is located.

Nucleus

Largest eukaryotic organelle that houses DNA and controls cellular activities.

Nuclear envelope

Double membrane surrounding the nucleus; continuous with rough ER.

Nuclear pore

Protein-lined channel in the nuclear envelope that regulates traffic between nucleus and cytoplasm.

Nucleolus

Dense, non-membranous region inside the nucleus where ribosomal RNA is synthesized and ribosome subunits assemble.

Chromatin

Complex of DNA and proteins that condenses into chromosomes during cell division.

Ribosome

Non-membranous organelle composed of rRNA and proteins; site of protein synthesis.

80S ribosome

Eukaryotic cytoplasmic ribosome consisting of 60S and 40S subunits.

70S ribosome

Prokaryotic ribosome; also found inside mitochondria and chloroplasts of eukaryotes.

Endomembrane system

Interconnected group of membranes that regulates protein traffic and metabolism (nuclear envelope, ER, Golgi, lysosomes, vesicles, vacuoles, plasma membrane).

Rough endoplasmic reticulum (RER)

ER studded with ribosomes; synthesizes secretory, membrane, and lysosomal proteins.

Smooth endoplasmic reticulum (SER)

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

Golgi apparatus

Stack of flattened cisternae that modifies, sorts, and ships products received from ER.

Cis Golgi

Golgi face that receives vesicles from the ER.

Trans Golgi

Golgi face that dispatches processed products to other destinations.

Lysosome

Membranous sac containing hydrolytic enzymes that digest macromolecules and worn-out organelles.

Autophagy

Lysosomal process that degrades damaged organelles within the cell.

Vacuole

Large membrane-bound vesicle derived from Golgi or ER; functions in storage and digestion.

Central vacuole

Large vacuole in mature plant cells that stores ions, wastes, and helps maintain turgor.

Contractile vacuole

Organelle in many protists that expels excess water for osmoregulation.

Mitochondrion

Double-membranous organelle that performs aerobic respiration and ATP production.

Cristae

Infoldings of the inner mitochondrial membrane that increase surface area for ATP-generating enzymes.

Chloroplast

Plant organelle containing chlorophyll; site of photosynthesis.

Thylakoid

Flattened membrane sac in chloroplast where light reactions of photosynthesis occur.

Granum

Stack of thylakoids within a chloroplast.

Peroxisome

Organelle containing oxidative enzymes (catalase) that break down fatty acids and detoxify H₂O₂.

Glyoxysome

Specialized peroxisome in plant seeds that converts fats into sugars during germination.

Cytoskeleton

Network of protein fibers (microtubules, microfilaments, intermediate filaments) that support cell shape and movement.

Microtubule

Hollow rod made of tubulin; involved in cell shape, chromosome movement, cilia, and flagella.

Centrosome

Microtubule-organizing center in animal cells, containing a pair of centrioles.

Centriole

Cylindrical structure of microtubules within the centrosome; forms spindle fibers.

Cilium

Short, numerous microtubule-based projection that moves fluid or cells; power-stroke motion.

Flagellum

Long, few in number microtubule-based projection that propels cells with whip-like motion.

Microfilament (Actin filament)

Thin strand of actin; involved in muscle contraction, cell motility, and cytokinesis.

Intermediate filament

Fiber made of keratin-like proteins; provides tensile strength and anchors organelles.

Cell wall

Rigid extracellular layer in plants, fungi, some protists, and bacteria; provides protection and shape.

Extracellular matrix (ECM)

Meshwork of glycoproteins (collagen, proteoglycans, fibronectin) surrounding animal cells.

Integrin

Transmembrane receptor that connects ECM to the cytoskeleton.

Plasmodesmata

Cytoplasmic channels through plant cell walls allowing intercellular communication.

Tight junction

Intercellular junction that seals neighboring animal cells to prevent leakage of extracellular fluid.

Desmosome

Anchoring junction that fastens cells together into strong sheets via intermediate filaments.

Gap junction

Communicating junction in animals that allows passage of ions and small molecules between cells.

Fluid mosaic model

Concept that membranes are dynamic bilayers of phospholipids with embedded, mobile proteins.

Phospholipid bilayer

Double layer of amphipathic phospholipids forming the fundamental structure of cell membranes.

Integral protein

Membrane protein embedded within the lipid bilayer; often functions as a transporter or receptor.

Peripheral protein

Protein loosely bound to the membrane surface; often involved in signaling or structural support.

Protein channel

Integral protein forming a hydrophilic pore for passive movement of specific ions or water.

Carrier protein

Membrane protein that changes shape to transport specific solutes across the membrane.

Cholesterol (membrane)

Steroid lipid interspersed among phospholipids that modulates membrane fluidity in animal cells.

Glycolipid

Lipid with covalently attached carbohydrate on the extracellular membrane surface; functions in cell recognition.

Glycoprotein

Protein with covalently attached carbohydrate on the extracellular membrane surface; acts as antigen or receptor.

Diffusion

Passive movement of molecules from high to low concentration down a gradient.

Facilitated diffusion

Passive transport of polar molecules or ions via specific transmembrane proteins.

Osmosis

Diffusion of water across a selectively permeable membrane from high to low water potential.

Hypotonic solution

External solution with higher water potential (lower solute concentration) than the cell; causes water influx.

Hypertonic solution

External solution with lower water potential (higher solute concentration) than the cell; causes water efflux.

Isotonic solution

External solution with equal water potential to the cell; net water movement is zero.

Active transport

Energy-requiring movement of substances against their concentration gradient via transport proteins.

Sodium–potassium pump

ATP-driven pump that exports 3 Na⁺ and imports 2 K⁺ to maintain electrochemical gradients in animal cells.

Proton pump

Transport protein that uses ATP to expel H⁺, creating an electrochemical gradient.

Cotransport

Coupled transport where downhill movement of one solute drives uphill movement of another.

Endocytosis

Active bulk transport that brings macromolecules into the cell via vesicle formation.

Phagocytosis

“Cell eating”; type of endocytosis in which the cell engulfs large particles or microbes.

Pinocytosis

“Cell drinking”; nonspecific uptake of extracellular fluid and dissolved solutes by endocytosis.

Receptor-mediated endocytosis

Selective endocytosis triggered by ligand binding to membrane receptors in coated pits.

Exocytosis

Active bulk transport that releases macromolecules from the cell by fusion of vesicles with the plasma membrane.