Culturing Microorganisms

• What is the process by which bacteria multiply?

  Binary fission
• How does a bacterial cell prepare to divide during binary fission?

  By replicating its genetic material before increasing in size
• What happens to the circular DNA during binary fission?

  A copy of each piece of circular DNA moves to each end of the cell
• What occurs after the circular DNA has moved to each end of the bacterial cell?

  The cytoplasm divides, and new cell walls form around each daughter cell
• How does the number of cells change with each division during binary fission?

  The number of cells increases by a power of 2 each time binary fission occurs
• What can be investigated using cultures of bacteria grown in the lab?

  The effect of disinfectants and antibiotics on microorganisms
• How quickly can some species of bacteria multiply under ideal conditions?

  As much as once every 20 minutes
• What do bacteria require to multiply quickly?

  An adequate supply of nutrients and an appropriate temperature
• What nutrients do bacteria need for rapid growth?

  Carbohydrates, proteins, minerals, and vitamins
• What is the maximum allowed temperature for bacterial growth in a school lab?

  25°C
• Why is it important to maintain a temperature below 25°C in a school lab?

  To prevent the growth of more harmful pathogens
• In what two forms can bacteria be grown in the lab?

  In a nutrient broth solution or as colonies on an agar gel plate
• Why is it vital to grow uncontaminated cultures of microorganisms in the lab?

  The presence of competing species can affect the growth of cultures and the validity of studies