Culturing microorganisms + practical

• What is the purpose of a culture medium in microbiology?


  To provide nutrients for microorganisms to grow
• What components are typically found in a culture medium?

  Carbohydrates, minerals, protides, and vitamins
• What are the two forms of culture medium mentioned?

  Nutrient broth solution and solid agar jelly
• How do visible colonies form on the surface of agar jelly?


  Microorganisms multiply and form colonies
• What is the first step in making an agar plate?


  Pour hot agar jelly into a petri dish
• What is the purpose of inoculating loops in culturing microorganisms?


  To transfer microorganisms to the culture medium
• At what temperature are microorganisms typically not kept in schools?


  Above 25°C
• Why are pathogens more likely to grow at temperatures above 25°C?


  Because they thrive in warmer conditions
• What is the method used to investigate the effects of antibiotics on bacterial growth?


  Place paper disks soaked in antibiotics on an agar plate
• What happens to antibiotic-resistant bacteria when exposed to antibiotics?


  They will grow around the disks
• What is an inhibition zone?


  A clear area where bacteria have died due to antibiotic exposure
• What should be done with a control disk in the antibiotic experiment?


  Use a control disk in sterile water
• How long should the experiment be left to run at 15°C?


  48 hours
• What does a larger area of inhibition indicate about an antibiotic?


  The antibiotic is more effective
• How do you calculate the size of the inhibition zones?


  By calculating the area of the inhibition zone
• What is the formula to calculate the area of an inhibition zone?


  Area = πr²
• What are the steps involved in culturing microorganisms?


  1. Prepare a culture medium with nutrients.
  2. Pour hot agar jelly into a petri dish.
  3. Allow the agar to cool and set.
  4. Use inoculating loops to transfer microorganisms.
  5. Incubate at a controlled temperature.
• What is the process for testing antibiotic effectiveness on bacteria?


  1. Soak paper disks in different antibiotics.
  2. Place disks on an agar plate with bacteria.
  3. Allow antibiotics to diffuse into the agar.
  4. Observe the inhibition zones after incubation.
  5. Compare the sizes of inhibition zones.