micro - virus and bacteria Intro Flashcards
Name 4 microbes and their classifications.
Bacteria (prokaryote)Protozoa (eukaryote)Fungi (eukaryote)Viruses (neither pro nor eu)
Bacteria
Prokaryote
Protozoa
eukaryote
Fungi
Eukaryote
Viruses
not prokaryotic or eukaryotic
2 basic shapes of bacteria
ROD (aka Bacillus) -2 together= diplobacilli-chains of bacilli = streptobacilli-other arrangements = palisades (side by side/ “X” “V” or “Y” figures)COCCIlittle circles - can make long beaded strings, clumps, tetrad, cubicles, or diploccoccus
Possible bacteria shapes
-rod-cocci-spirochetes (flexible undulating corkscrew)-spirillum (RIGID corkscrew shape)-diplococci-diplobacilli
bacterial chromosome:
in nucleoid…basically 1 chromosome, tightly packed
Mesosome:
chromosomal DNA attached to the bacterial membrane, invaginated at the site of bacterial division(small dark circular part…as opposed to large white nucleoid…)
Plasmid DNA:
self-replicating unit of DNA distinct from the chromosome - IMPORTANT - much smaller than chrom, but contain very important info like antibiotic resist. genes, etc. (A specific plasmid will make it resistent to specific antibiotic.) Some are mobile - can transfer between bacterium (REMEMBER: sometimes even between diff. bact. species. ALSO remember antibiotic resis. frequently resides in plasmids)
Ribosomes and Granules:
Bacteria have no ribosomes…no endoplasmic reticulum…individual protiens are diffferent from those in Euk. whatever is external is highly antigenic (we make antibodies to it, especially things like flagella)
Flagella:
- used by bacteria for locomotion- composed of flagellin- different arrangements of flagella: (not so important as simple - are they mobile or not)monotrichouslophotrichousamphitrichousperitrichous (multiple flagella)
Flagellar motor:
Mostly know: some bacteria can move with presence of flagella and flagella antingens help diagnose cause of disease and therefore tell what antibiotic to use to treatotherwise, made of protein flagellin, has a filament and a basal region (basal body = rod and rings). Gram+ have 2 rings; gram- have 4 rings.
Pili (fimbriae)
shorter and finer than flagella- 2 types: adherence pili (attach bacteria to surfaces) sex pili (important in bacterial conjugation; found in some gram- bacteria)
Capsule
- slimy outer coating externally produced - not found in all bacteria- usually a complex of high molec. weight polysaccharides- called Slime or Glycocalyx (generally more loosely associated- adherence properties) - think biofilms: some bacteria produce biofilm on replacement knees, hips, etc. - can be antiphagocytic(what bacteria have/produce/can do is dictated by genetic info and by environment)[very important that body recognizes it as forieng…body cells envelop cells and phagocytize them. but the glycoclyx or capsule on some bacteria keeps that from happening]
cytoplasmic membrane
-encloses bacterial cytoplasm-phospholipid bilayer - selectively permeable-embedded with proteins-site of nutrient transport- SITE OF RESPIRATION
peptidoglycan - cell wall
60-90% of gram+ cell wall; much less in gram-UNIQUE COMPONENT OF BACTERIA - THEREFORE USEFUL FOR FIGHTING BACTERIA
cell wall:
structure determines staining properties - use in IDing bacteria
n-acetyl-glucose aminen-acetyl-nuramic acid
NAM and NAG - make up peptidoglycansome have peptide attached to that (unique to individual bacteria)peptide hangs off…there is cross-linking between tetrapeptides
penicillin
inhibits cross-linking between tetrapeptidesso much pressure in cell it lysesso peptidoglycan = extremely important
do all bacteria have NAM and NAG?
yes - different types of tetrapeptides, can be crosslinked by another peptide or directly to one another, depending on species, but cross-linking always occurs.
Gram+ bacteria
have MUCH MORE peptidoglycan in cell walls - much more easy to get things inside gram+ relative to gram-
Gram - Bacteria
much less peptidoglycan; has outer envelope that helps things come in or out; MUCH MORE DIFFICULT to get things in/out of gram- than gram+ especially large structures
gram stain
developed by Hans Christian Gram- Gram+ retain purple iodine-dye complexes after treatment w/decolorizing agent; gram- bacteria do not retain complexes when decolorized - safranin is then used to counterstain the gram-: Chrystal violet comes in, turns all cells blueIodine comes in, forms large complexAlcohol takes away cell membrane/phospholipid molecules (decolorizes gram- but not gram+ so much peptidoglycan in gram+, the crosslinking prevents the complexes that formed from leaving - they are locked in) + stays blue.