BIO 21 Quiz Ex 15

Which microorganisms work together in yogurt fermentation?

• E. coli and S. aureus

• S. thermophilus and L. delbrueckii subsp. bulgaricus

• B. subtilis and M. luteus

• S. cerevisiase and Rhizopus sp.

What is the main substrate broken down during yogurt fermentation?

• Fructose

• Glucose

• Lactose

• Maltose

The fermentation process in yogurt occurs under what condition?

• Aerobic

• Anaerobic

• Under UV light

Why should the milk be cooled after heating before adding the yogurt?

• To make the yogurt thicker

• To increase sugar concentration

• To pasteurize the milk

• To prevent killing the bacterial culture

What is the main acid produced during yogurt fermentation?

• Lactic acid

• Citric acid

• Acetic acid

• Hydrochloric acid

Fermentation does not require:

• Microorganisms

• Sugar

• Oxygen

What staining method is used to examine bacteria in yogurt?

• Acid-fast stain

• Gram stain

• Spore stain

• Simple stain

The breakdown of sugar during yogurt fermentation occurs through:

• Glycolysis

• Krebs cycle

• Citric acid cycle

• Photosynthesis

TRUE or FLASE: Fermentation is used to preserve food and improve its taste.

• TRUE

• FALSE

TRUE or FALSE: After inoculation, the yogurt containers are left uncovered for aeration.

• TRUE

• FALSE