BIOL 3052 Lecture Notes - Lecture 13: Klebsiella Pneumoniae, Treponema Pallidum, Neisseria
28 Jan 2017
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Document Summary
Different size, shape and arrangement of bacterial cells. Bacteria are prokaryotic, unicellular microorganisms, which lack chlorophyll pigments. The cell structure is simpler than that of other organisms as there is no nucleus or membrane bound organelles. Due to the presence of a rigid cell wall, bacteria maintain a definite shape, though they vary as shape, size and structure. When viewed under light microscope, most bacteria appear in variations of three major shapes: the rod (bacillus), the sphere (coccus) and the spiral type (vibrio). Structure of bacteria has two aspects, arrangement and shape. So far as the arrangement is concerned, it may paired (diplo), grape-like clusters (staphylo) or. In shape they may principally be rods (bacilli), spheres (cocci), and spirals (spirillum). The average diameter of spherical bacteria is 0. 5-2. 0 m. For rod-shaped or filamentous bacteria, length is 1-10 m and diameter is 0. 25-1 . 0 m.
