Classifying different organsims

  • Differentiate between pro and eu

Has: nucleoid (place where DNA is located), cytoplasm, ribosomes, ella, pilus (2 types, attachment structure and sex for gene transfer), capsule, 1- cell wall, 2 - cell membrane

Difference between pro and eu:  

Pro - no nucleus, has cell wall, unicellular, no membrane bound organelles

Viruses < bacteria < fungi < eu

  • Identify common bacterial morphologies

Cocci - round

Bacilli - rods

Spirochetes - spiral shaped

Clustered - staphylococcus 

Chain-like - streptococcus

Diplo - double

Vibrio - comma

Branching - actinomyces

Straight rod - E-coli


  • Differences between G+, G- and acid-fast bacteria based cell wall types

G+ = thick, has LTA (endotoxin), no peri-plasmic space, no lipopolysaccharide 

G- = thin, no LTA, peri-plasmic space, lipopolysaccharide (endotoxin), pentaglycine bridge

  • Mechanisms of Gram stains and Acid fast stains

  • Clinical implications of capsule + biofilm

  • LTA (mild) and LPS (mild or severe) cause toxic shock


  • Identify bacterial motility structures as cell appendages

Bacterial Cell Wall (best drug target)

  • Functions include: protection from osmotic pressure, rigid structure

  • Carries virulence factors (disease causing molecules)

  • site of antibiotic action

  • ‘Cillin’ target the cell wall (i.e. pencillin, amoxycillin, ampicillin)

  • Site of action for body defense (lysozyme target, saliva, tears)


Atypical

  • Involution forms - swollen/aberrant

  • Pleomorphic - variations in shape/size (haemophilus)

  • Cell wall deficient - lack of cell wall (mycoplasma)


Gram Staining

  • Based on cell wall

  • Gram + = blue

  • Gram - = red/pink

  • Third type - non gram staining (ex. Mycoplasma b/c no cell wall, mycobacteria (too much lipid

Gram Stain

  • Crystal violet, iodine (mordant, fixes the dye), alcohol/acetone (decolourizing), safranin (counter stain)

  • If Gram + = it will stay a lighter violet

  • If Gram - = in acetone will lose colour, in the counter stain, it will become pink because of the thin cell wall


Mycobacteria - TB causing, too much lipid


Acid Fast Stain

  • Carbon fuchsin, acid-alcohol (decolorizer), methylene blue stain (counterstain)

  • AF+ will retain the fuchsia, AF- blue/purple


Cytoplasmic Membrane

  • Phospholipid bilayer - pro has no sterols

  • Mycoplasma is an exception, DOES contain sterols

  • Site of oxidative phosphorylation and ETC b/c of no mitochondria

  • Transportation (active + passive)


Bacterial Components

  • ella - made of ellin protein, motility, has filament, basal body and hook, chemotaxis

Spirochetes have corkscrew motility, tumbling

  • Pili - made of pilin protein, on Gm- bacteria

Attachment pili - infection by attaching to epithelial cells, removal of pili will remove disease UTI

pili - gene transfer

  • Capsule - gelatinous material that covers the wall, virulence, anti-phagocytic, vaccines, quelling

  • Biofilm - layer called glycocalyx outside cell wall, when well organized/not easily washed off = capsule, if easily washed off = slime layer

Biofilm = community of microorganisms attached to a surface, bacteria present in watery environments, can be seen on artificial surfaces, requires monitoring 

  • Bacterial granules - food storage, volutin granules can be used in staining

  • Nucleoid - area where bacteria have DNA

  • Plasmid - transmissible + non-transmissible

Exotoxin + antiviral resistance

  •  Transposons - genes, can jump/move, can change expression, drug resistance 

  • Bacterial spore - resting/dormant bacteria, non-reproductive cell, spore coat = high resistant (bacillus, clostridium), killed by autoclave


Bacteria - rigid peptidoglycan cell wall

Fungus - chitin cell wall