Lecture 1.3 Study Notes

Microscope Definition

An instrument that magnifies objects too small to be seen with the naked eye.

Brightfield Microscopy

A standard illumination technique used in light microscopy.

Phase Contrast Microscopy

Highlights differences in density within transparent specimens. (often has a “halo”)

Scanning Electron Microscopy (SEM)

Displays 3D surfaces of cells using electron beams.

What is light microscopy best for?

Best for living cells, general structures

Electron Microscopy Resolution

Achieves a resolution of 0.2 nm, significantly better than light microscopy.

Historical Development of Cell Theory

Cell theory established in the 1830s-1860s by Hooke, Schleiden, Schwann, and Virchow.

Microscopy's Impact on Cell Biology

Enhanced understanding of cellular structures, leading to breakthroughs in biology.

Cells

The fundamental building blocks of all living organisms.

Magnification

The factor by which an image appears larger compared to the actual size.

Resolution

The capacity to distinguish two points as separate entities.

Contrast

Variation in brightness or color that makes cell structures visible.

Fluorescence Microscopy

Utilizes fluorescent dyes/proteins to highlight specific molecules or structures.

Electron Microscopy

Uses electron beams instead of visible light for high-resolution imaging.

Transmission Electron Microscopy (TEM)

Reveals internal ultrastructure of cells.

Differential Interference Contrast (DIC)

Produces a 3D-like appearance of transparent cells.

Robert Hooke

First to observe and coin the term 'cell' from cork.

Antonie van Leeuwenhoek

First to observe living, motile cells with high-resolution lenses.

Cell Theory

All living organisms are composed of cells; cells are the basic unit of life.

Matthias Schleiden

German botanist who stated that all plants are composed of cells.

Theodor Schwann

Proposed that both plant and animal cells are the basic units of life.

Rudolf Virchow

Noted that every cell arises from pre-existing cells.

what is fluorescence microscopy best for?

best for specific molecules, dynamic processes. can visualize location, movement, and interactions of cellular components

what is electron microscopy best for?

best for ultrastructure, fine detail