01:119:115 Lecture Notes - Lecture 5: Phagocytosis, Nuclear Lamina, Endoplasmic Reticulum
18 Apr 2016
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Document Summary
Cells too small to be seen by naked eye. Microscopes sophisticated better understanding of cell. Magnification: ratio of an object"s image size to its real size. Resolution: measure of clarity of image or min distance of two points. Contrast: differences in brightness between parts of the sample. Compound light microscope: 2 lens (ocular and objective) Stains used to increase contrast between structures. Focuses beam of electrons through or off of specimen. Beam of electrons on surface of specimen. Electrons strike surface secondary electrons emitted intensity varies with contour. Object coated with a thin film of gold. Cut into very thin slices (50-100 nm thick) Sections stained with heavy metals to improve contrast. Takes cells apart separates major organelles. Centrifuges fractionate cells into their component parts. Used to determine the functions of organelles. Dna in a nucleus bounded by a membrane. Cytoplasm in region between plasma membrane and nucleus. Eukaryotic cells ~ 10x larger than prokaryotic cells.
