Prokaryotic and Eukaryotic Cell Structures

Vocabulary flashcards covering essential structures and comparative features of prokaryotic and eukaryotic cells.

Plasma Membrane (Prokaryotic)

Phospholipid bilayer with embedded proteins that regulates substance exchange in bacteria and archaea.

Cell Wall (Prokaryotic)

Rigid peptidoglycan (bacteria) or pseudopeptidoglycan (archaea) layer providing shape and protection from osmotic stress.

Capsule (Glycocalyx)

Optional carbohydrate-protein coat that aids moisture retention, surface attachment, and evasion of host defenses.

Nucleoid

Irregular region containing a single circular chromosome; lacks a surrounding nuclear envelope.

Plasmid

Small, circular DNA molecule carrying extra genes (e.g., antibiotic resistance) that can be transferred between cells.

Ribosome 70S

Prokaryotic ribosome (50S + 30S subunits) where protein synthesis occurs.

Cytoplasm

Gel-like interior where metabolic reactions take place and ribosomes are distributed.

Cytoskeleton-like Structures (Prokaryotic)

Primitive actin/tubulin homologues that help maintain cell shape and spatial organization.

Intracellular Inclusions / Micro-compartments

Protein-based structures containing enzymes for specialized metabolism such as gas vesicles or magnetosomes.

Pili / Fimbriae

Short hair-like projections used for adhesion, conjugation, and surface attachment.

Prokaryotic Flagellum/Flagella

Rotating helical filament that propels the cell; present in motile species.

Endospore

Dormant, highly resistant structure formed by some bacteria to survive extreme conditions.

Plasma Membrane (Eukaryotic)

Selective barrier that regulates molecular exchange, cell communication, and homeostasis in eukaryotes.

Cell Wall (Eukaryotic)

Cellulose (plants) or chitin (fungi) wall providing structural support and protection.

Nucleus

Membrane-bound organelle housing linear DNA with histones and controlling gene expression.

Nucleolus

Dense nuclear region where rRNA is transcribed and ribosomal subunits are assembled.

Ribosome 80S

Eukaryotic ribosome (60S + 40S subunits) responsible for protein synthesis in cytosol or on ER.

Rough Endoplasmic Reticulum

Ribosome-studded membrane network where newly synthesized proteins are folded and processed.

Smooth Endoplasmic Reticulum

Membranous network involved in lipid synthesis, detoxification, and calcium storage.

Golgi Apparatus

Stacked sacs that modify, sort, and package proteins and lipids into vesicles for delivery.

Mitochondrion

Double-membrane organelle producing ATP via respiration; contains its own DNA of endosymbiotic origin.

Lysosome

Acidic vesicle rich in hydrolytic enzymes that degrades macromolecules, old organelles, and pathogens (mainly in animal cells).

Peroxisome

Organelle that detoxifies hydrogen peroxide and oxidizes fatty acids; abundant in liver cells and germinating seeds.

Vacuole

Membrane-bound compartment for storage and transport; central vacuole in plants also maintains turgor pressure.

Cytoskeleton (Eukaryotic)

Network of microtubules, microfilaments, and intermediate filaments supporting shape, motility, and intracellular transport.

Centrosome

Microtubule-organizing center in animal cells that duplicates and forms the mitotic spindle during cell division.

Centriole

Cylindrical microtubule structure located in pairs inside the centrosome, aiding spindle and basal body formation.

Cilia / Eukaryotic Flagella

9+2 microtubule projections that generate cell movement or fluid flow across cell surfaces.

Chloroplast

Double-membrane plastid in plants and algae where photosynthesis occurs; contains thylakoids and its own DNA.

Extracellular Vesicle (Exosome)

Small membrane vesicle released for intercellular communication, carrying RNA, proteins, and other biomolecules.