01:119:115 Lecture Notes - Lecture 5: Microscope, Electron Microscope, Archaea

• School: Rutgers University
• Department: Biological Science
• Course: 01:119:115
• Professor: Stern Cardinale

Document Summary

Multicellular organisms: cooperative specialized cells all cells share: Cells are too small to be seen by the naked eye. Invention of microscope lead to the discovery of the cell. Refract (bend) the light to magnify the image. Magnification: the ratio of an object"s image size to its real size. Resolution: the measure of the clarity of the image, or the minimum distance of two distinguishable points. Contrast: differences in brightness between parts of the sample. Stains or dyes are used to increase contrast between structures: electron microscope (em) Focuses beam of electrons through or off specimen. Electrons strike surface -> secondary electrons emitted -> intensity varies with contour. Object coated with thin film of gold: transmission electron microscopes (tems) Cut into very thin slices (50-100 nm thick) Basic features of all cells: plasma membrane, cytosol: semifluid substance, chromosomes (carry genes, ribosomes (make proteins) Prokayotes: ~3. 5 to 3. 8 bya: eukaryotes: ~1. 9 - 2. 1 bya.