RP2

• What technique is used to prepare uncontaminated bacterial cultures?

  Aseptic technique
• What should you be able to describe by the end of the video?

  Preparing uncontaminated cultures and antibiotic effects
• How do 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?

  To grow and divide bacteria
• Why does the broth appear cloudy?

  It contains a large number of bacteria
• What is an agar gel plate?

  A petri dish with solid nutrient broth
• What chemical is used to solidify nutrient broth into agar gel?

  Agar
• What is the purpose of sterilizing petri dishes and nutrient broth?

  To kill unwanted microorganisms
• How is bacteria transferred into the culture?

  Using an inoculating loop
• How do you sterilize an inoculating loop?

  Pass it through a flame
• Why do we attach the lid of the petri dish with adhesive tape?

  To prevent contamination
• At what temperature do we normally incubate bacteria in schools?

  25 degrees Celsius
• Why do we incubate agar plates upside down?

  To prevent moisture from disrupting colonies
• What is the first step in investigating the effect of antibiotics on bacterial growth?

  Clean the bench with disinfectant
• Why do we open a sterile agar gel plate near a Bunsen burner flame?

  The flame kills bacteria in the air
• What do we place on the agar plate to test antibiotics?

  Sterile filter paper disks containing antibiotics
• What is the area around the antibiotic disc where bacteria do not grow called?

  Zone of inhibition
• How do you calculate the area of the zone of inhibition?

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

  $452.45 \text{ mm}^2$
• What are the steps to prepare an uncontaminated bacterial culture using aseptic technique?

  1. Sterilize petri dishes and nutrient broth
  2. Sterilize inoculating loop by passing through flame
  3. Transfer bacteria using the loop
  4. Attach lid with adhesive tape
  5. Incubate agar plate upside down at 25°C
• What are the steps to investigate the effect of antibiotics on bacterial growth?

  1. Clean the bench with disinfectant
  2. Sterilize inoculating loop by passing through flame
  3. Open sterile agar plate near Bunsen burner
  4. Spread bacteria evenly over the plate
  5. Place antibiotic disks on the plate
  6. Incubate at 25°C and observe results
• What are the key components of a bacterial culture setup?

  • Nutrient broth solution
  • Agar gel plates
  • Inoculating loop
  • Petri dishes
• What are the implications of incubating bacteria at 25 degrees Celsius?

  • Reduces harmful bacteria growth
  • Suitable for educational settings
  • Slower growth rate compared to higher temperatures