Prokaryotic vs. Eukaryotic Cells – Key Vocabulary

Vocabulary flashcards covering essential terms related to prokaryotic and eukaryotic cell structure, classification, genetics, and reproduction.

Prokaryote

Cell type whose name comes from Greek ‘pro’ (before) + ‘karyon’ (nut / kernel), meaning "before the nucleus."

Eukaryote

Cell type whose name comes from Greek ‘eu’ (true) + ‘karyon’ (nut / kernel), meaning "true nucleus."

Escherichia coli

Common single-celled prokaryotic bacterium found in the human digestive tract; model organism.

Nucleoid

Region in a prokaryotic cell where the single circular DNA molecule is located.

Three-Domain System

Modern biological classification that divides life into Archaea, Bacteria, and Eukarya.

Archaea

Domain of prokaryotes with diverse cell walls and unique membrane lipids forming monolayer membranes.

Bacteria

Domain of prokaryotes with peptidoglycan cell walls; target of antibiotics like penicillin and vancomycin.

Peptidoglycan

Carbohydrate matrix cross-linked by short polypeptides; main component of most bacterial cell walls.

Mycoplasma

Bacterial genus (class Mollicutes) lacking a cell wall, making it resistant to antibiotics targeting peptidoglycan.

Monolayer Membrane

Single-layer membrane formed by archaeal lipids where saturated hydrocarbons are covalently linked to glycerol at both ends.

Magnetosome

Prokaryotic compartment with iron-oxide crystals that orients the cell along magnetic fields.

Organelle

Membrane-bound structure performing a specific function in eukaryotic cells; generally absent in prokaryotes.

Pilus (plural: Pili)

Hair-like prokaryotic appendage used primarily for DNA transfer during conjugation.

Fimbriae

Short, numerous prokaryotic surface structures that help cells adhere to surfaces.

Plasmid

Small, circular DNA molecule in prokaryotes separate from chromosomal DNA; often carries accessory genes.

Centrioles

Cylindrical eukaryotic organelles involved in spindle formation and cell division.

Plasmodesmata

Microscopic channels that traverse plant cell walls, allowing intercellular communication.

Bacterial Flagellum

Rotary motor appendage powered by a proton gradient, enabling bacterial locomotion.

Archaellum

Rotary locomotor structure in Archaea, evolutionarily related to pili and powered by ATP hydrolysis.

Eukaryotic Flagellum

Whip-like appendage composed of microtubules (9 + 2 structure) producing wave-like motion.

Proton Gradient

Difference in proton concentration across a membrane that drives bacterial flagellar rotation.

ATP Hydrolysis

Energy-releasing breakdown of ATP; powers rotation of archaeal archaella.

Histone Protein

Protein around which eukaryotic DNA coils, forming nucleosomes.

Introns

Non-coding regions within eukaryotic genes removed from pre-mRNA during processing.

Exons

Coding regions of eukaryotic genes that remain in mature mRNA after splicing.

Svedberg Unit (S)

Unit describing sedimentation rate of particles; indicates ribosome size (70S prokaryotic, 80S eukaryotic).

Binary Fission

Asexual reproduction in prokaryotes where a cell divides into two genetically identical cells.

Conjugation

Prokaryotic DNA exchange process using a pilus; often involves an F plasmid donor and recipient.

Transformation

Genetic alteration of a prokaryote by uptake of free DNA from the environment.

Transduction

Gene transfer between bacteria mediated by a virus (bacteriophage).

Surface-Area-to-Volume Ratio

Relationship influencing cell size; smaller cells have higher ratios, aiding nutrient exchange.

Thiomargarita namibiensis

One of the largest known bacteria, up to 100–300 µm in diameter.