1. Naomi Kinjal Asaad Binoy
MICROSCOPES
Naomi Kinjal Asaad Binoy

2. Microscopy
Magnification is the ratio of an object’s image size to the real size
Resolution is a measure of the clarity of the image; it is the minimum distance two points can be separated and still distinguished as two points

3. Different Types of Microscopes
Light-visible- light is passed through the specimen and then through a glass lens. Specimen can be living or not; stained. Resolving power is limited by the wavelength of visible light.
Electron-focuses a beam of electrons through the specimen or onto it’s surface; helps see cell organelles but not living specimen. Resolving power is larger since wavelengths of electrons are smaller than light

4. Electron Microscopy Techniques
Scanning electron microscopy (SEM)-micrographs taken with a scanning electron microscope show a 3-D image of the surface of a specimen. useful for the detailed study of the surface of the specimen
Transmission electron microscopy (TEM)-a transmission electron microscope profiles a thin section of a specimen. used to study the internal ultrastructure of cells

5. Light Microscopy Techniques
Brightfield (unstained specimen)-passes light directly through specimen
Brightfield (stained specimen)-staining with various dyes enhances contrast
Phase-contrast-enhances contrast in unstained cells by amplifying variations in density within specimens
Differential-interference-contrast (Nomarski)-uses optical modifications to exaggerate differences in density
Fluorescence-shows the locations of specific molecules in the cell by tagging the molecules with fluorescent dyes or antibodies
Confocal-a technique that uses a pinhole aperture to eliminate out-of-focus light from a thick sample

6. Uses for Microscopes
Tissue Analysis-common for studying cells and tissues
Studying the Role of a Protein within a Cell-helps study proteins in live cells
Studying Atomic Structures-helps study the surfaces of individual atoms

7. Facts
Cell walls were first seen by Robert Hooke in 1665 as he looked through a light microscope at dead cells from the bark of an oak tree
It took Antoni van Leeuwenhoek's crafted lenses to help visualize living cells
Cell biology advanced rapidly in the 1950s with the introduction of electron microscope
Most cells are between 1 and 100 micrometers in diameter and are therefore visible only under a microscope
Microscopes are the most important tools of cytology, the study of cell structure
Modern cell biology developed from an integration of cytology with biochemistry

8. Limitations Size of specimen Encounter diffraction
Many cells are transparent and colorless- staining can kill specimen