Prokaryotes vs. Eukaryotes Quiz

Prokaryotes vs. Eukaryotes

• Representative microorganisms: Prokaryotes include all bacteria; eukaryotes include algae, fungi, protozoa, plants, and animals.
• Genetic system location: Prokaryotes have nucleoid (chromatin body/nuclear material); eukaryotes have a nucleus.
• Nucleus: Prokaryotes lack a nucleus, and eukaryotes have a true nucleus with a nuclear membrane and nucleoli.
• Chromosome arrangement: Prokaryotes have a single circular chromosome without histones; eukaryotes have multiple linear chromosomes with histones.
• Introns in genes: Introns are rare in prokaryotes and common in eukaryotes.
• Cell division: In prokaryotes, the process is binary division, without mitotic division, and no meiosis or DNA fragments exchange. Eukaryotes use mitotic nuclear division and often involve meiosis when reproduction is sexual.
• Sexual reproduction: Prokaryotes don't usually use meiosis; eukaryotes often do.
• Cell wall: Prokaryotes often have a cell wall, usually chemically complex (peptidoglycan) in most bacteria. In eukaryotes, cell walls are either absent or chemically simple.
• Plasma membrane: Prokaryotic membranes don't typically contain sterols. Eukaryotic membranes often contain sterols, and sometimes contain parts of the respiration and photosynthesis machinery.
• Cytoplasmic streaming: Absent in prokaryotes and present in eukaryotes.

Additional Prokaryotic Features

• Ribosomes: Small size (70S) and distributed in the cytoplasm.
• Inclusion bodies: Storage of carbon, phosphate, and other substances.
• Nucleoid: Location of genetic material (DNA).
• Periplasmic space: Contains hydrolytic enzymes and proteins for nutrient processing.
• Cell wall: Provides shape and protection from lysis.
• Capsules and slime layer: Resistance to phagocytosis and adherence to surfaces.
• Fimbriae and pili: Attachment and bacterial mating.
• Flagella: Movement.
• Endospores: Survival under harsh conditions.
• Cell wall and pellicle: Strengthens and shapes the cell.
• Locomotive organelles (flagella): Simple fibril type.
• Pseudopodia: Present in some types.
• Metabolic mechanisms: Wide variety, including anaerobic energy yielding reactions, some fix nitrogen gas, and may accumulate poly-hydroxybutyrate as a reserve material.
• G+C% in DNA: 25-75% in some prokaryotes, 40% in others.

Additional Eukaryotic Features

• Plasma membrane: Mechanical cell boundary, selectively permeable, with transport systems and mediating cell-cell interactions and adhesion.
• Cytoplasmic matrix: Environment for organelles, many metabolic processes, and cell structure/movements.
• Microfilaments, intermediate filaments, and microtubules: Cell structure and movements.
• Endoplasmic reticulum: Transport of materials; protein (rough ER) and lipid (smooth ER) synthesis.
• Golgi apparatus: Packaging and secretion of materials.
• Mitochondria: Energy production through the tricarboxylic acid cycle and electron transport.
• Lysosomes: Intracellular digestion.
• Chloroplasts: Photosynthesis.
• Nucleus: Repository for genetic information, control center for the cell.
• Nucleolus: Ribosomal RNA synthesis, ribosome construction.
• Cell wall and pellicle: Strengthens and shapes the cell.
• Cilia and flagella: Cell movement.
• Vacuoles: Temporary storage and transport.
• Pinocytosis: (Absent in prokaryotes, often in eukaryotes)
• Cytoskeleton: (Absent in prokaryotes, usually present in eukaryotes)
• Gas vacuoles: Can be present in prokaryotes for buoyancy.
• Membrane-bound vacuoles: (Absent in many prokaryotes) in many eukaryotes (e.g., true vacuoles).