2: culturing microorganisms

• 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
• How often can bacteria double in number under suitable conditions?

  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 made from?

  Nutrient broth and agar
• Why is it important to avoid contamination when culturing bacteria?

  To ensure accurate experimental results
• What is the first step in avoiding contamination?

  Sterilize petri dishes and nutrient broth
• How do we sterilize an inoculating loop?

  By passing it through a flame
• What is done after transferring bacteria onto the dish?

  Attach the lid with adhesive tape
• Why do we place the agar plate upside down in the incubator?

  To prevent moisture from disrupting colonies
• At what temperature do we normally incubate bacteria?

  25 degrees Celsius
• Why do we incubate bacteria at 25 degrees Celsius?

  To reduce harmful bacteria growth
• What is the purpose of using a sterile agar gel plate in the investigation?

  To prevent contamination
• What is the zone of inhibition?

  Area where bacteria do not grow
• How do we measure the effect of antibiotics on bacterial growth?

  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 squared
• If the radius of the zone of inhibition is 12 mm, what is the area?

  452.45 square mm
• What is the value of PI used in calculations?

  3.14
• What should you be able to describe after watching the video?

  Preparing cultures and investigating antibiotics