Microbiology - microorganisms

• Characteristics of microorganisms:

  • Bacteria
  • Viruses
  • Prions
  • Fungi
  • Protozoa
• genetic material:

  DNA

  • Chromosome:
  • how the DNA is packaged

  Gene:

  • the small segment of DNA that makes proteins and chorosomes.
• lipids: fats

  functions of lipids:

  • cell membrane structure
  • energy (storage)
  • protection (cushion)
• Protein: (long chain of amino acids)

  functions of protein:

  • work (action)
  • structure
  • cell recognition
  • energy
• fluid Mosaic Model:

  Model of cell membrane

  A) Carbohydrates

  B) Lipids

  C) Protein

  
• carbohydrates: (sugars) su ga r

  functions of Carbs:

  • energy
  • structure
  • cell recognition
• microorganisms:

  cellular - Prokaryotes, Eukaryotes

  acellular

  A) Viruses

  B) Prions

  C) Bacteria

  D) Animal cells

  E) Plant cells

  F) Fungi

  G) Protozoa

  
• cellular microorganisms

  A) Prokaryote

  B) Eukaryote

  
• major similarities between Prokaryotes and Eukaryotes:

  • cytoplasm in cell
  • ribosomes throughout cell
  • DNA is the genetic material
  • cell (plasma) membrane
• major differences between Prokaryotes and Eukaryotes

  A) No nucleus

  B) Single chromosome

  C) No organelles

  D) Complex cell wall

  E) Smaller

  F) Simpler

  G) Contains a nucleus

  H) Multiple chromosomes

  I) Contains organelles

  J) Simple or no cell wall

  K) Larger

  L) Complex

  
• Taxonomy:

  categorizing living organisms
• The 5 Kingdoms:

  • in 1969, Robert Whittaker proposes organizing all organisms into Kingdoms:

  A) Eukaryotes

  B) Prokaryotes

  C) Plantae

  D) Fungi

  E) Animalia

  F) Protista

  G) Monera

  
• the kingdoms:

  A) Bacteria

  B) Protozoa, slime molds

  C) Plants, algae

  D) Mushrooms, molds, yeast

  E) Vertebrates, insects

  
• The 3 Domains:

  • in 1970s, Carl Woese proposes 3 domain system:
  • bacteria (common Ancestor)
  • Archaea (common Ancestor)
  • Eukarya
• classifying human beings:

  1. Domain
  2. kingdom: Animalia
  3. Phylum: Chordata
  4. Class: Mammalia
  5. Order: Primates
  6. Family: Hominoidea
  7. Genus: Homo
  8. Species: Sapiens (subspecies, strains, varieties)
• Binomial Nomenclature:

  • Genus: 2 or more species with similar morphology.
  • Species: groups of organisms with similar genetics:
  • for microbes, 70% genetic similarity.
  • for plants/animals, same species can breed.
• Binomial Nomenclature:

  how do you write the name

  Homo sapiens. Escherichia coli

  Genus - first letter capitalized

  Species - all lower case

  Both words underlined or in italics
• Abbreviated Forms:

  Escherichia coli = E. coli

  Streptococcus pneumoniae = S. pneumoniae

  viruses are named differently:

  e.g: AIDS virus :

  Human Immunodeficiency Virus (HIV)
• other mane designations:

  Strains:

  microbes within a species with some genetic change, e.g:

  E. coli 0157:H7
• microbial size:

  units of measure:

  • micrometer (qm) is a unit of measurement.
  • 1 millimeter (mm) = 1000 micrometers (qm)
  • 1 millimeter (mm) = 1000000 nanometers (nm)
• Typical sizes:

  A) Human being = 1.6 m

  B) Bacterium = 1 to 5 qm

  C) Virus = 50 to 250 nm

  
• Cell: as an example

  A) Epithelia cell

  B) Nucleus

  C) Bacteria

  
• microscopes: two kinds

  A) Compound light

  B) 100-1000x

  C) Electron

  D) Over 20 million x

  E) Viral

  F) Single

  
• 2 forms of electron microscopy:

  1. Scanning electron microscopy (SEM)
  2. Transmission electron microscopy (TEM)

  A) Scanning

  B) Transmission

  
• fluorescence microscopy:

  • used to positively identify any specific microbe
  • Application: bacterial or viral identification
  • microbe-specific antibody + fluorescent ‘tagged’ antibody.
  • antibodies added to unknown microbe, then washed.
  • microbe exposed to UV light
• Fluorescence Microscopy:

  Application: bacterial or viral identification

  • “positive” microbes fluoresce under UV light

  
• classification leads to…

  identification

  identifying characteristics:

  • cell morphology
  • staining reactions
  • motility (moving)
  • colony morphology (how they grow)
  • atmosphere requirements
  • nutritional requirements
  • biochemical & metabolic activities
  • specific enzymes (colours)
  • pathogenicity (what affect of ppl)
  • genetic composition
  • antigens interactions
• Bacterial morphology:

  refers to:

  cell shape & arrangement

  • rod-shaped
  • bacillus (pl. bacilli)
  • spherical or round
  • coccus (pl. cocci)
  • curved or wavy
  • curved rod - vibrio
  • rigid wave - spirillum (pl. spirilla)
  • flexible wave - spirochete

  A) Bacillus

  B) Coccus

  C) Vibrio

  D) Spirillum

  E) Spirochete

  
• bacterial morphology :

  other arrangements:

  • Streptobacillus
  • Cocci
  • Pairs
  • diplococcus
  • Chain
  • streptococcus
  • grape-like cluster
  • staphylococcus

  A) Streptobacillus

  B) Diplococcus

  C) Streptococcus

  D) Staphylococcus

  
• staining techniques:

  • used to help visualize bacteria
  • used to help identify bacteria
  • used to help differentiate different kinds of bacteria
• 3 major staining techniques:

  1. Simple Stain:

  -stains all bacteria same color

  2. Gram Stain:

  -differentiate type of cell wall

  3. Acid-Fast Stain:

  -identifies mycobacteria
• common to all staining:

  • place a small drop of bacterial sample on slide (smear)
  • heat fix the sample:

  -kills bacteria

  -sticks to slide
• Simple Stain:

  • a basic (+ve) dye stains all bacteria

  -crystal violet is most common

  • water washes away access stain

  
• The Gram Stain:

  Gram (+ve)

  Gram (+ve)

  A) +

  B) -

  
• Gram Stain:

  A) Positive

  B) Purplr

  C) Iodine

  D) Blue-purple

  E) Alcohol wash

  F) Remains blue-purple

  G) Safranin

  H) Remains blue-purplr

  I) Negative

  J) Purple

  K) Blue-purple

  L) Losses stain

  M) Orange-red

  N) Mordant

  
• so, the difference:

  A) Protein

  B) Carbohydrate

  C) Cell wall

  D) +

  E) Lipids

  F) Proteins

  G) Cell membrane

  H) -

  I) Outer membrane

  J) Lipids

  K) Protein

  L) Cell wall

  M) Protein

  N) Carbohydrate

  O) Cell membrane

  P) Lipids

  Q) Protein

  
• So who cares…

  A) +

  B) Penicillin

  C) Staphylococcus aureus

  D) Escherichia coli

  E) -

  F) Tetracycline

  G) Toxins

  H) Membrane

  
• and this one…

  A) Cocci

  B) Negative

  C) Chlamydia trachomatis

  
• acid-fast stain:

  • similar to Gram stain (2 stains used), except:

  1. Red stain is used first
  2. Heat is used to help first stain penetrate
  3. Acid/alcohol is used to wash the first stain
  4. Blue stain stains all other cells for contrast

  A) Waxy cell wall

  B) Cell wall

  C) Cell membrane

  D) Mycobacteria

  E) TB

  
• bacterial envelope:

  A) Glycocalyx

  B) Cell wall

  C) Cell membrane