Microbiology and Immunology 3820A Midterm: Micro #2 midterm review
22 Nov 2016
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Classification/bacterial structure and fnx: classification of infectious agents. Abnormal beta pleated sheets that mess up the alpha helix. Viruses: nucleic acid (dna or rna) genes packaged in protein coats which can subvert host cells to replicate virus particles. Note: viruses and prions are not cells (cid:894)are(cid:374)"t li(cid:448)i(cid:374)g(cid:895) Subcellular organelles (i. e. chloroplasts, mitochondria (actually bacteria rickettsias)) We cannot survive without bacteria (i. e. mitochondria for energy) Cell wall none, rigid or flexible. Osmotic barriers, found in prokaryote and plant cells. Aerobic: tolerate significant concentrations of ambient oxygen, does not imply use of oxygen. Anaerobic: poisoned by significant concentrations of ambient oxygen. In 1884: bacteria classified into two groups whether or not they are decolourized by alcohol after staining with gentian violet and iodine. Today we use: crystal violet instead of gentian violet. A red counterstain (safranine) to stain the decolourized (gram negative) organisms. Gram-positive cell wall: simple thick layer of peptidoglycan outside of the cell mb.
