BIOL 2051 Lecture Notes - Lecture 2: Eyepiece, Numerical Aperture, Oil Immersion
Document Summary
Small size allows nutrients to reach all parts of cell quickly. Prokaryotic cells can be as small as 0. 2 m. Cocci- typically has diameter of 2 m. Some microbiologists have proposed that bacteria smaller than 0. 2 m exist in nature called nanobacteria. If one considers the space needed to house all essential molecules of life, it is unlikely they could exist within a volume available in a cell less than 0. 1 m. Prokaryotic cells can have a wide variety of cellular morphologies, which are often helpful in identification. Arrangement: coccus- single cell, diplococcus- 2 cells, streptococcus- chains of more than 2 cells, staphylococcus- grapelike clusters of cells, tetrads- packets of 4 cells, most common shape is rods. Can be very long & thin or short & fat. Occur singly or in chains: spirals. Rigid spiral-shaped bacteria are called spirilla (singular-spirillum) Simple microscopes: one lens, magnify 50-300x. Compound microscopes: multiple lenses, much higher magnification. 1: focuses light rays up through specimen.
