Microbiology Glossary
Browse key terms, biological classifications, and microscopy techniques. Filter terms in real-time using the search console.
Tardigrade
Microscopic animals with extreme survival capabilities, able to enter a dormant state called cryptobiosis. Also known as water bears due to their slow, lumbering walk.
Cryptobiosis
A physiological state in which metabolic activity is reduced to a near-zero level, enabling survival under extreme conditions such as freezing, radiation, vacuum, or complete desiccation (anhydrobiosis).
Protist
A diverse group of eukaryotic microorganisms, mostly single-celled, that do not belong to the animal, plant, or fungi kingdoms (e.g., amoebae, paramecia, euglena).
Ciliate
Single-celled eukaryotic organisms characterized by the presence of hair-like organelles called cilia, which they beat in waves to swim and sweep food into their oral groove (e.g., paramecia, stentors).
Diatom
A major group of single-celled photosynthetic algae with cell walls made of silica (glass). They are found in oceans and freshwater and generate about 20% of the Earth's oxygen.
Cyanobacteria
Photosynthetic prokaryotic bacteria. Historically, they generated the Earth's oxygen-rich atmosphere and are considered the ancestors of plant chloroplasts.
Darkfield Illumination
A method that blocks direct light, allowing only scattered light from the sides to reach the objective. Organisms glow brightly against a dark background, revealing clear contours without staining.
Polarized Light Microscopy
A technique using polarizing filters to observe birefringent materials like cell walls, starch grains, or crystals, producing high-contrast colored images against a dark background.
Suspension
A fluid mixture in which microscopic organisms or fine solid particles are uniformly dispersed throughout a liquid without settling out.
Flagellate
Single-celled organisms that swim using one or more whip-like structures called flagella for propulsion and sensory inputs (e.g., euglena, phacus).
Slime Mold
Organisms that feed as single amoeba-like cells but can aggregate to form a giant multinucleated protoplasm (plasmodium). Known for solving mazes to find the shortest route to food.
Cover Slip
A very thin square of transparent glass (usually 0.13–0.17 mm thick) placed over a drop of liquid specimen on a slide, spreading the liquid evenly and protecting the microscope lens.