Bacteria Growth Requirement

Question 1

What are the growth requirements of bacteria?

Answer 1

oxygen, carbon dioxide, nutrients, temperature, hydrogen and Ion concentration (pH)

Question 2

Classifications of bacteria according to the needs of oxygen

Answer 2

Aerobes - Organisms that require oxygen for growth

Anaerobes - Organisms that grow best in an atmosphere of reduced oxygen tension

Question 3

Classifications of bacteria according to the needs of Carbon dioxide

Answer 3

Capnophiles - organisms that need 5%-10% carbon dioxide to live, an atmosphere that can be provided by a candle jar.

examples:

• Haemophilus influenza
• Neisseria gonorrheae
• Streptococcus pneumoniae

Question 4

Classifications of bacteria according to the needs of Nutrients

Answer 4

a. autotrophs
b. heterotrophs
c. phototrophs
d. chemotrophs

Question 5

Classifications of bacteria according to the needs of optimal temperature for growth

Answer 5

a. Psychrophile / Cryophile - 0̊C - 15̊C (Listeria monocytogenes)
b. Mesophile - 20̊C - 45̊C (most pathogenic bacteria grow at this temperature)
c. Thermophile -50̊C - 60̊C (Bacillus stearothermophillus)
d. Hyperthermophile - 80̊C - 113̊C (Sulfolobus)

Question 6

Classifications of bacteria according to the needs of Hydrogen and Ion Concentration (pH)

Answer 6

a. Acidophile – pH: 0 – 5.5 = Sulfolobus
b. Neutrophile – pH: 5.5 - 8.0 = Eschirichia coli
c. Alkalophile – pH: 8.5 – 11.5 = Vibrio choler