Microbiology

• How do bacteria reproduce?

  Bacteria reproduce by binary fission
• Under suitable conditions, how often can bacteria double in number?

  Every 20 minutes
• What is a nutrient broth solution used for in bacterial culture?

  • Contains all the nutrients bacteria need to grow and divide
  • Appears cloudy due to a large number of bacteria
• What are agar gel plates and how are they used in bacterial culture?

  • Contain nutrient broth that has been solidified into a jelly using agar
  • Used to culture bacteria in a petri dish
  • Allow bacteria to grow into visible colonies
• Why is it important to avoid contamination when preparing bacterial cultures?

  To prevent unwanted microorganisms from affecting the culture
• What is the first step in preparing a bacterial culture to avoid contamination?

  Carefully sterilize the petri dishes, bacterial nutrient broth, and agar
• How is an inoculating loop sterilized before use?

  By passing it through a flame, such as a Bunsen burner
• What is done after transferring bacteria onto the dish to prevent contamination?

  The lid is attached using adhesive tape
• At what temperature are bacteria typically incubated in schools?

  25 degrees Celsius
• Why is the agar plate placed upside down in the incubator?

  To prevent moisture from dripping down and disrupting the colonies
• What is the purpose of using a disinfectant solution on the bench before starting the experiment?

  To kill microorganisms that could contaminate the culture
• How is the inoculation loop used in the investigation of antibiotics on bacterial growth?

  To spread the chosen bacteria evenly over the agar plate
• What is placed on the agar plate to investigate the effect of antibiotics?

  Sterile filter paper disks containing antibiotic
• What is the zone of inhibition?

  A region where bacteria do not grow around the antibiotic disc
• How can the effect of the antibiotic be measured?

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

  Area = $\pi R^2$, where $R$ is the radius
• If the radius of the zone of inhibition is 12 millimeters, what is the area?

  The area is approximately $452.45 \text{ mm}^2$
• Why is it important to handle the bacterial culture as though it were dangerous?

  To maintain safety and prevent contamination
• What should be done before handling the microbe?

  Set up equipment and wash hands thoroughly
• Where should the agar plates be opened during the practical?

  Near the Bunsen burner
• What is the purpose of marking the agar plate into three sections?

  To prepare for inoculation with different substances
• Where should the agar plate be labeled?

  At the bottom, not the lid
• What should be done if the work area has not been disinfected?

  Wash hands before continuing
• What does turning the Bunsen burner to a blue flame create?

  A sterile environment
• Why is it important to flame the lid of the bottle before using it?

  To ensure the lid is sterile
• What should be done after inoculating the agar plate with bacteria?

  Spread the bacteria evenly over the plate
• What happens to the bacteria after they are spread on the agar plate?

  They will grow and form colonies
• What is the purpose of using antibiotic disks in the experiment?

  To test their effectiveness in killing bacteria
• What is the expected outcome if the antibiotic is effective?

  There will be a clear ring around the disk
• How should the agar plate be stored after inoculation?

  Upside down to prevent condensation
• Why is it important to disinfect the table after the experiment?

  To prevent spreading bacteria to others
• What can be measured to analyze the effectiveness of the treatments?

  The diameter of the clear areas around the disks
• How can the results of this experiment be applied to real-world situations?

  To determine effective treatments for bacterial infections
• What are the steps involved in preparing and inoculating an agar plate with bacteria?

  1. Wash hands and set up equipment.
  2. Prepare agar plates and label them.
  3. Create a sterile environment with a Bunsen burner.
  4. Use a sterile pipette to transfer bacteria.
  5. Spread bacteria evenly over the agar plate.
  6. Apply antibiotic disks for testing.
  7. Store the plate upside down in an incubator.
• What factors should be considered when analyzing the effectiveness of different antibacterial treatments?

  • Diameter of clear areas around disks
  • Viscosity of liquids used
  • Method of diffusion through agar
  • Fairness of the test conditions