Biological Science – Chapter 7: Inside the Cell

Vocabulary flashcards covering the key terms, structures, and processes from Chapter 7 "Inside the Cell," including prokaryotic and eukaryotic cell components, organelles, cytoskeletal elements, and intracellular transport systems.

Cell Theory

States that all organisms are composed of cells.

Protein (cell component)

Macromolecule that performs most of the cell’s functions.

Nucleic Acid

Stores, transmits, and processes genetic information.

Carbohydrate (cell component)

Provides chemical energy, carbon, support, and cellular identity.

Plasma Membrane

Selectively permeable membrane barrier surrounding the cell.

Eukaryote

Cell type that possesses a membrane-bound nucleus.

Prokaryote

Cell type that lacks a membrane-bound nucleus.

Domain Bacteria

Evolutionary lineage of prokaryotic organisms characterized by fatty-acid phospholipids.

Domain Archaea

Prokaryotic lineage with branched isoprenoid phospholipids.

Domain Eukarya

Evolutionary lineage containing eukaryotic organisms.

Transmission Electron Microscopy (TEM)

Imaging technique that revealed the complexity of prokaryotic cells.

Cytoplasm

All cellular contents enclosed by the plasma membrane.

Chromosome (prokaryotic)

Large circular DNA molecule with associated proteins located in the nucleoid.

Nucleoid

Region in prokaryotes where the chromosome is organized.

Plasmid

Small, circular, supercoiled DNA molecule in prokaryotes carrying auxiliary genes.

Supercoiling

DNA packing method that condenses large prokaryotic chromosomes.

Ribosome

Large and small subunits of RNA and protein that synthesize polypeptides.

Cytoskeleton (prokaryotic)

Protein filament network essential for division and shape maintenance in bacteria and archaea.

Photosynthetic Membrane

Internal membrane system in some prokaryotes converting light to chemical energy.

Organelle (prokaryotic)

Membrane-bound compartment in certain bacteria performing specialized tasks.

Cell Wall (prokaryotic)

Fibrous layer providing protection, shape, and rigidity; contains peptidoglycan in bacteria.

Peptidoglycan

Primary polysaccharide component of bacterial cell walls.

Flagellum (prokaryotic)

Long filament that rotates to propel a bacterial or archaeal cell.

Fimbriae

Needle-like surface projections that attach prokaryotes to surfaces or other cells.

Organelle (eukaryotic)

Membrane-bound compartment that divides cell volume and performs specialized functions.

Cytosol

Fluid portion of the cytoplasm in eukaryotic cells.

Nucleus

Large double-membrane compartment housing chromosomes and nucleolus.

Nuclear Envelope

Double membrane surrounding the nucleus containing pore complexes.

Nuclear Lamina

Lattice of fibrous proteins lining inner nuclear envelope, maintaining nuclear shape.

Nucleolus

Nuclear region where rRNA is synthesized and ribosomal subunits assemble.

Free Ribosome

Cytosolic ribosome synthesizing proteins destined for cytosol or organelles.

Bound Ribosome

Ribosome attached to rough ER, producing secretory or membrane proteins.

Endoplasmic Reticulum (ER)

Extensive membrane factory continuous with the nuclear envelope.

Rough ER (RER)

ER region studded with ribosomes; synthesizes and folds secretory proteins.

Smooth ER (SER)

ER region lacking ribosomes; synthesizes lipids and stores Ca²⁺ ions.

Lumen (ER)

Interior space of the ER where proteins fold and undergo processing.

Golgi Apparatus

Stacked cisternae that process, sort, and ship proteins from RER.

Cis Face (Golgi)

Golgi side facing the nucleus, receiving vesicles from ER.

Trans Face (Golgi)

Golgi side oriented toward plasma membrane, dispatching vesicles.

Cisternae

Flattened membrane sacs composing the Golgi apparatus.

Lysosome

Animal-cell recycling center containing acid hydrolase enzymes.

Acid Hydrolase

Digestive enzyme in lysosomes functioning optimally at pH 5.

Endomembrane System

Integrated network of ER, Golgi, and lysosomes for protein and lipid trafficking.

Vacuole

Large plant or fungal organelle for storage, digestion, or defense.

Peroxisome

Organelle where redox reactions detoxify compounds; generates and degrades H₂O₂.

Glyoxysome

Plant peroxisome that converts fats to sugar precursors.

Mitochondrion

Double-membrane organelle producing ATP via cellular respiration.

Cristae

Infoldings of the inner mitochondrial membrane increasing surface area.

Mitochondrial Matrix

Internal fluid of mitochondria containing enzymes and mitochondrial DNA.

mtDNA

Mitochondrial DNA that replicates and encodes some mitochondrial proteins.

Chloroplast

Photosynthetic organelle in plants and algae with three membranes.

Thylakoid

Flattened sac inside chloroplast where light reactions occur.

Granum (Grana)

Stack of thylakoids within a chloroplast.

Stroma

Chloroplast fluid containing enzymes for sugar synthesis.

Endosymbiosis Theory

Idea that mitochondria and chloroplasts originated from engulfed bacteria.

Eukaryotic Cytoskeleton

Network of protein fibers providing shape, stability, and intracellular transport.

Cell Wall (eukaryotic)

Stiff outer layer in fungi, algae, and plants providing structural support.

Extracellular Matrix (ECM)

Protein-polysaccharide network supporting animal cells in lieu of a wall.

Pulse–Chase Experiment

Technique using radiolabeled molecules to track protein movement through cells.

Secretory Pathway

Route from RER through Golgi to the plasma membrane for protein secretion.

ER Signal Sequence

N-terminal 20-amino-acid zip code directing proteins to RER.

Signal Recognition Particle (SRP)

Cytosolic protein that binds ER signal sequence and guides ribosome to RER.

Translocon

Channel through which nascent polypeptide enters the ER lumen.

Glycosylation

Addition of carbohydrate side chains to proteins, forming glycoproteins.

Mannose-6-Phosphate

Golgi-added tag that targets proteins to lysosomes.

Exocytosis

Fusion of a vesicle with the plasma membrane to release contents externally.

Endocytosis

Uptake of materials via plasma-membrane invagination and vesicle formation.

Receptor-Mediated Endocytosis

Selective uptake of ligands bound to surface receptors into endocytic vesicles.

Phagocytosis

Engulfment of large particles or cells into phagosomes for digestion.

Autophagy

Self-eating process that degrades damaged organelles via autophagosomes and lysosomes.

Actin Filament (Microfilament)

Smallest cytoskeletal fiber composed of actin subunits; involved in cell movement.

Myosin

Motor protein that interacts with actin filaments using ATP for movement.

Intermediate Filament

Rope-like fiber (e.g., keratins, lamins) that resists tension and anchors organelles.

Nuclear Lamins

Intermediate filaments forming the nuclear lamina beneath the envelope.

Microtubule

Largest cytoskeletal element; hollow tube of α- and β-tubulin dimers.

Microtubule Organizing Center (MTOC)

Site where microtubules originate; the centrosome in animal cells.

Centrosome

Animal-cell MTOC containing two perpendicular centrioles.

Kinesin

ATP-dependent motor protein that walks toward microtubule plus ends carrying vesicles.

Dynein

Motor protein that moves toward microtubule minus ends; drives cilia/flagella bending.

Vesicle

Small membrane-bound sac transporting cargo within cells.

Flagellum (eukaryotic)

Long whip-like extension with 9 + 2 microtubule axoneme driving cell movement.

Cilium

Short hair-like projection with 9 + 2 axoneme that moves fluid or the cell.

Axoneme

Core structure of cilia/flagella comprising 9 doublet + 2 singlet microtubules.

Basal Body

Organelle at cilium/flagellum base; template for axoneme assembly.

Nuclear Pore Complex

Massive protein assembly perforating nuclear envelope and regulating transport.

Nuclear Localization Signal (NLS)

17-amino-acid zip code directing proteins into the nucleus.

Dynamic Instability

Property of microtubules to rapidly grow and shrink at plus ends.

Cytoplasmic Streaming

Actin-myosin-driven flow of cytosol and organelles in plant/fungal cells.

Cell Crawling

Actin-based protrusion and movement of animal cells or amoebae.

Mitochondrial Network

Interconnected, fused mitochondria formed by frequent fusion events.

Endocytotic Vesicle

Membrane sac formed during endocytosis transporting material into the cell.

Early Endosome

Initial sorting compartment formed after receptor-mediated endocytosis.

Late Endosome

Maturing endocytic compartment destined to fuse with lysosomes.

Autophagosome

Double-membrane vesicle enclosing cytoplasmic material for degradation by lysosomes.

Centrioles

Pair of microtubule bundle structures within the centrosome.

Peptidoglycan Outer Membrane

Additional glycolipid membrane external to Gram-negative bacterial cell walls.

Isoprenoid Chains

Branched hydrocarbon tails in archaeal phospholipids.