M2:T3: Cell morphology

• describe cellular microbes

  • small but complex
  • structures have specific functions: effects how microbes respond to the environment
• eukaryotoes microbes have

  • focus on size and shape
  • Protozoa
  • algae
  • fungi
• prokaryotic microbes

  • ribosomes
  • cytoplasm
  • membrane
  • nucleoid
• shape of prokaryotes

  1. cell wall will determine shape
  2. cocci: sphere shape
  3. rod/bacilli: cylinder shape
• other shapes

  1. spiral: curved rod through to tightly coiled bacteria
  2. appendages: extension of bacteria and attaches to surface
  3. other: squared and star
• arrangement

  1. diplococcus: 2 cells that are not separated
  2. streptocci: chain of cells
  3. staphylocci: cells in circular arrangement
• common cell diameters and length

  diameter: 0.5-2um

  length: 1-5 um
• starvation state


  enables organisms to shrink
• why do smallest bacteria under starvation state shrink

  they reduce the volume, higher surface area:volume, important in environments with low nutrients
• 4 different bacterial cell envelops

  1. gram positive: 2 layers, thick CW and cell membrane
  2. gram negative: 3 layers, thin CW, outer and inner membrane
  3. acid fast: micro-bac, lipid layer, membrane, finish CW
  4. mycoplasma: no cell wall