module 4 - mcb 11 lab

• Culture Media

  • Nutrient materials prepared for growing and cultivating

  microorganisms in the laboratory.
• pH

  A) ACIDOPHILE

  B) NEUTROPHILE

  C) ALKALIPHILE

  
• Agar

  • Almost all solid media has this as its component.

  • Solidifying agent with no nutritive value.
• agar melts at 100C and solidifies at 40C
• Chemically defined/synthetic – exact chemical composition
• Complex medium – exact composition is not known; extracts and digests of yeasts, meat, or plants; undefined components
• EXAMPLES of complex medium: nutrient agar, EMBA
• Nutrient Agar and Eosin Methylene Blue Agar, both of which have peptone.
• medium

  A) 1.5-2.0

  B) 0

  C) 0.5-0.7

  
• General purpose – allows growth of most organisms
• Selective medium - promotes the growth of a specific organism and at the same time, inhibits the growth of unwanted microorganisms.
• Mannitol Salt Agar - Staphylococcus, while inhibiting the growth of most bacteria due to its high salt content.
• differential medium - allows differentiation of microorganisms, usually have indicator dyes which can distinguish one group of microorganism from another based on the color resulting from their metabolic reactions.
• Enrichment

  – increase the number of desired microorganisms to detectable levels
• Cotton plugs - permit the interchange of gases but not the passage of microorganisms in the air, thereby preventing contamination of the medium.
• Characterization – test for metabolic activities
• volume

  A) 20ml

  B) 10ml

  C) 8ml

  D) 5ml

  E) 3ml