Concept 4.1: Biologists use microscopes and biochemistry to study cells

Vocabulary flashcards covering key microscopy concepts, historical figures, light vs. electron microscopy, scale, and common organelles.

Microscopy

The use of instruments to study cells and other structures too small to be seen with the naked eye; includes light and electron microscopes.

Light microscope (LM)

A microscope that passes visible light through a specimen and through glass lenses to magnify the image.

Magnification

The ratio of an image’s size to the actual size of the object.

Resolution

The ability to distinguish two nearby objects as separate.

Contrast

Difference in brightness or color that helps distinguish structures in a specimen.

Hooke

Robert Hooke; first to describe plant cell walls in 1665 while examining cork.

van Leeuwenhoek

Antoni van Leeuwenhoek; used refined lenses to observe living cells and microorganisms.

Animalcules

Historic term used for microscopic living organisms; van Leeuwenhoek referred to them as 'very little animalcules'.

Transmission Electron Microscope (TEM)

An electron microscope that transmits electrons through a specimen to image internal details; high resolution.

Electron microscope (EM)

Microscope that uses electrons instead of light; includes TEM and SEM.

Scanning Electron Microscope (SEM)

An electron microscope that scans the surface of a specimen to reveal topography, often with a gold coating.

Gold coating (SEM sample)

Thin film of gold applied to a specimen to eject secondary electrons for imaging.

Super-resolution microscopy

Techniques that surpass the diffraction limit of light to resolve smaller details than conventional light microscopy.

Unaided eye

The human eye without any optical aid; used as a reference for scale.

Ribosome

A small molecular machine (~10 nm) that synthesizes proteins in cells.

Nucleus

Organelle (~10 μm) containing the cell’s genetic material.

Mitochondrion

Organelle (~1 μm) that produces ATP through cellular respiration.

Virus

Very small infectious agents (~100 nm) that require electron microscopy to visualize.

Bacteria

Microscopic single-celled organisms; typically around 1 μm in size.

Wavelength

Distance between successive crests of a wave; shorter wavelengths yield higher imaging resolution.

Topography

The surface features and contours of a specimen, best revealed by SEM.

TEM orientation

The orientation of tissue sections in TEM determines which type of cross-section is visible.