01:119:100 Lecture Notes - Lecture 13: Horizontal Gene Transfer, Crystal Violet, Cell Membrane
12 Jul 2015
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Bio lecture 13 10/16/12 prokaryotes and viruses. Intro: domains bacteria, archaea, dominant, body 70 trillion cells, bacterial cells 700 trillion, pervasive, morphology fig 25-1, size, o. 5 1, volume 1/1000 of eukaryotic cell, shape, coccus (cocci): balls/spheres i. ii. iii. Staphylococcus cluster/clump: bacillus (baccili): rods, spirals i. ii. iii. Two amino sugars that are linked by short polypeptides. Found only in doman bacteria: differences in cell wall composition - gram stain i. Gram positive very thick cell walls, made of peptidoglycan. Pick up and retain lots of crystal violet stain. Penicillin interferes with peptidoglycan synthesis ii. Gram negative cell wall has only a thin peptidoglycan layer. Do not retain the crystal violet stain. Surrounding the peptidoglycan later, is an outer membrane (very thick) consists of lipopolysaccharides (lps) toxin . Important in locomotion: endospore dormant stage, survive unfavorable environmental conditions, reproduction, genetic material found in nuclear area, singular, circular dna molecule b.
