Unit 5

What is the optimum growth temperature for psychrophiles?

• -5ºC to 15ºC

• 25⁰C to 45⁰C

• 45⁰C to 70⁰C

• 70⁰C to 110⁰C

Which type of bacteria grow best at moderate temperatures?

• Psychrophiles

• Mesophiles

• Thermophiles

• Hyperthermophiles

Where are thermophiles commonly found?

• Arctic and Antarctic regions

• Streams fed by glaciers

• Hot springs and compost heaps

• Ocean at hydrothermal vents

What is the ideal growth temperature for hyperthermophiles?

• -5ºC to 15ºC

• 25⁰C to 45⁰C

• 45⁰C to 70⁰C

• 70⁰C to 110⁰C

Which microorganisms require the presence of oxygen for growth?

• Obligate aerobes

• Microaerophiles

• Obligate anaerobes

• Aerotolerant anaerobes

What is the oxygen requirement for microaerophiles?

• High concentration of oxygen

• Moderate concentration of oxygen

• Low concentration of oxygen

• No oxygen

Which microorganisms grow only in the absence of oxygen?

• Obligate aerobes

• Microaerophiles

• Obligate anaerobes

• Aerotolerant anaerobes

What is the energy source for facultative anaerobes?

• Aerobic respiration

• Anaerobic respiration

• Fermentation

• Both aerobic respiration and fermentation

At what pH range do neutrophiles grow best?

• Below 5.5

• 5 to 8

• Above 8.5

• None of the above

Which microorganisms grow best at a pH below 5.5?

• Neutrophiles

• Acidophiles

• Alkaliphiles

• None of the above