microbial world (topic one)

• how microbes are invovled in our lives

  1. medicine - antibiotics
  2. food - yogurt, kimchi
  3. decomposition of dead animals
  4. infectious diseases
  5. environmental impact - nitrogen fixation, bioremediation
• nitrogen fixation

  release of excessive nitrogen into atmosphere, and causes more reactive N compounds to form (NH4, etc)

  a biological process in which the nitrogen gas is converted into a usable form for plants and other microbes (by nitrogen fixing microorganisms)
• bioremediation

  use of microbes and bacteria to remove contaminants, pollutants and toxins from soil, water, etc.
• binomial nomenclature

  scientific naming of living organisms based on the binomial system
• how to name BAFT (bacteria, alage, fungi, protozoa)

  • (genus) (species)
  • name must be italicized (typed out)/name must be underlined(written)
• bacteria

  • the only microorganism that is prokaryotic (no nucleus)
  • unicellular form only
  • peptidoglycan cell
• fungi (structure)

  • eukaryote
  • feeds on living/dead organisms(heterotrophic)
  • both unicellular (yeast) and multicellular (bread mold) forms
  • chitin cell wall
  • all fungi are non-motile
• algae (sturcture)

  • eukaryote
  • can photosynthesze(synthesize own food using sunlight and CO2, autotrophic)
  • both unicellular and multicellular forms
  • cellulose cell wall
• protozoa (structure)

  • unicellular form ONLY
  • heterotrophic
  • relatively large compared to bacteria, unicellular fungi and unicellular algae
  • no cell wall ( still has a membrane that helps contain contents)
  • SOME move using pseudopodia (ameoba)/cillia/flagella
• virus (structure)

  • acellular (not composed of cells)
  • "non-living", not capable fo reproduction by itself (considered particles)
  • requires a living host cells to replicate/reproduce
  • no cell wall, may have envelope
• symbiosis

  different organisms living together and interacting with one other
• symbiosis - mutualism

  (++)

  • both organisms benefit from the interaction
  • e.g. E. coli in our intestines synthesizes vitamin K (which we need) while we provided shelter & food
• symbiosis - commensalism

  (+0)

  • only one organism benefit from the interaction
  • the other neither benefits/suffers (e.g. normal microflora)
• parasitism

  (+-)

  • only one benefits, while other suffers
  • any microorganism that can cause diseases called pathogen
• pathogen

  microorganism/microbe that has the potential to cause diseases
• infection

  entry and multiplication of pathogenic microbes in an individual/population
• normal flora

  • relationship may be mutualism, parasitism or commensalism
  • all internal organs and most parts of the body are axenic (free from microbes)
  • exposed surfaces are colonised by microbes
  • normal flora can be resident or transient
• resident flora

  • resides permanently on your body
  • cannot be removed, even through washing
  • colonize our bodies soon afetr birth
  • (most common: staphylococcus epidermidis)
• transient flora

  • microorganisms that are transferred from the environment onto our bodies
  • temporarily stays on body (hours, days, etc)
  • (most common: staphylococcus aures)
• benefit of microflora

  prevents esthablishment of pathogens

  • competing for available nutrients
  • producing products that will inhibit/kill other microbes

  primes immune system

  produces nutirents (e.g. vitamin)
• harmful effects of normal flora

  • under abnormal conditions, normal flora can cause diseases (when flora found on skin enters body, open wounds, host immunity compromised(from AIDS,HIV)balance of normla flora is distrubed)
  • become opportunistic pathogens (not originally pathogen, but due to abnormal conditions, they become pathogens)
• microorganisms serve as - producers

  • autotrphs (algae, photosynthetic bacteria)
  • converts solar energy into chemical energy, and fixing carbon
• microorganisms serve as - consumers

  • all heterotrphs (bacteria, fungi, protozoa, humans)
  • feed on producers and themselves preyed upon by other consumers
• microorganisms serve as - decomposers

  • bacteria and fungi
  • recycle nutrients and make them available to the other life forms/nature
• biogeochemical cycles

  microorganisms recycle nutrients in the environment

  • making nutrients like C , N available to other life forms
  • returns nutrients to their respective reserviors
• carbon cycle

  • fungi and bacteria are invovled in decomposition
  • algae, photosynthetic bacteria are involved in fixing atmospheric CO2
• microorganisms nitrogen cycle

  almost all the nitrogen fixation that occurs on our planet is cerried out by bacteria
• microorganisms AS food - fungi

  mushrooms
• microorganisms AS food - algae

  kelp
• microorganisms AS food - bacteria

  fatt-choy
• microbial products used in foods - flavor enhancer

  monosodium glutamate
• microbial products used in foods - nutritional supplements

  vitamins and amino acids
• microbial products used in foods - acidulants

  citric acids
• microbial products used in foods - gelling agents

  agar
• microbial enzymes

  e.g. in the food industry, meat tenderizer
• food spoilage/poisoning

  • microbial metabolic by-products can make foods inedible (curdling of milk)
  • can cause food spoiling (toxins produced - foodborne illness)
• industrial chemical production

  microbial fermentation (e.g. ethanol)
• pharmaceuticals

  antibiotics/vaccines
• antibiotics

  many produced by microbes (e.g. penicillin)
• staining - meaning of the colours

  pink - Gram-negative, thin peptidogycal cell wall (doesnt retain primary stain, takes up secondary stain)

  purle - Gram-positive, thick peptidoglycan cell wall (retains primary stain)