Fluorescent

Definition

Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It occurs when molecules absorb photons at one wavelength and emit them at a longer wavelength.

5 Must Know Facts For Your Next Test

1. Fluorescence microscopy is widely used to visualize structures in biological specimens.
2. Fluorescent dyes, known as fluorophores, are used to stain specific components of cells.
3. The emitted light in fluorescence is usually of lower energy than the absorbed light, resulting in a shift from shorter to longer wavelengths (Stokes shift).
4. Common fluorescent tags include GFP (Green Fluorescent Protein) and DAPI (which binds to DNA).
5. Quenching can occur when molecules that fluoresce lose their ability to emit light due to interactions with other substances.

Review Questions

• What is the principle behind fluorescence?
• How do fluorophores work in the context of fluorescence microscopy?
• What is the Stokes shift and why is it important in fluorescence?

Related terms

fluorophore: A fluorescent chemical compound that can re-emit light upon light excitation.

quenching: The process by which fluorescence is decreased due to external factors such as molecular interactions.

GFP (Green Fluorescent Protein): A protein that exhibits bright green fluorescence when exposed to blue or ultraviolet light.