Micro lab

Microorganism

A microscopic organism, typically single-celled, that can exist independently or in colonies, including bacteria, archaea, fungi, protozoa, algae, and viruses.

Bacteria

Prokaryotic, unicellular organisms lacking a nucleus, often with peptidoglycan in their cell walls. Some bacteria are harmless, while others can cause diseases.

Archaea

Prokaryotic organisms similar to bacteria but with distinct biochemistry and genetics, typically found in extreme environments.

Eukarya

Eukaryotic organisms that possess a true nucleus, including animals, plants, fungi, and protists, which can be unicellular or multicellular.

Microscope Purpose

Used to observe microorganisms and structures too small to be seen with the naked eye, studying details of cells and tissues.

Bright Light Microscope Parts

Includes eyepiece, objective lenses, stage, stage clips, coarse and fine focus knobs, condenser lens, diaphragm, light source, arm and base.

Total Magnification Calculation

Total magnification equals eyepiece magnification multiplied by the objective lens magnification.

Magnification

The ability of a microscope to enlarge an image of a specimen.

Resolving Power

The ability of a microscope to distinguish between two points that are close together.

Brightfield Microscopy

Microscopy suitable for stained or naturally pigmented samples.

Phase Contrast Microscopy

Best for viewing transparent, unstained specimens like live cells.

Fluorescence Microscopy

Used for specimens labeled with fluorescent dyes to detect specific components.

Electron Microscopy

Used for viewing extremely small structures like viruses or sub-cellular organelles.

Aseptic Technique

Practices used to prevent contamination by microorganisms during laboratory procedures.

Endosymbiotic Theory

Theory proposing that certain organelles, like mitochondria and chloroplasts, were once free-living prokaryotic organisms engulfed by eukaryotic cells.

Saprobes

Organisms that feed on dead or decaying organic matter, including fungi, which recycle nutrients.

Dimorphism in Fungi

The ability of some fungi to exist in two forms depending on environmental conditions, affecting their pathogenicity.

Colony-forming unit (CFU)

A unit used to estimate the number of viable microorganisms in a sample, indicating how many colonies arise from a single viable organism.

Gram-Positive Bacteria

Bacteria that retain the crystal violet stain and appear purple under a microscope due to a thick peptidoglycan cell wall.

Gram-Negative Bacteria

Bacteria that do not retain the crystal violet stain and instead take up the safranin counterstain, appearing pink.

Selective Toxicity

The ability of a drug to target microbes without harming the host.

Antiseptic

A substance used on living tissue to inhibit or kill microorganisms.

Disinfectant

A chemical agent used to destroy microorganisms on non-living surfaces.

Antibiotic

A substance produced by microorganisms that inhibits or kills other microorganisms.

Kirby-Bauer Test

A method used to determine the susceptibility of bacteria to antibiotics by measuring the zone of inhibition around antibiotic discs.