Questions: Question 15 Which of the tubes pictured contains a facultative anaerobe? B E A D C

Solution Steps

Facultative anaerobes are organisms that can grow in both the presence and absence of oxygen. They prefer oxygen, as it allows for more efficient energy production, but can switch to anaerobic respiration or fermentation when oxygen is unavailable.

The dots in the tubes represent bacterial growth. Tube A shows growth concentrated at the top, indicating an obligate aerobe (requires oxygen). Tube B shows growth concentrated at the bottom, suggesting an obligate anaerobe (cannot tolerate oxygen). Tube C shows growth throughout the tube, denser at the top, which is characteristic of a facultative anaerobe. Tube D displays growth primarily in the middle, pointing towards a microaerophile (prefers low oxygen levels). Tube E shows scattered growth, suggesting an aerotolerant anaerobe (doesn't use oxygen but isn't harmed by it).

Tube C exhibits the growth pattern of a facultative anaerobe, with growth throughout the tube and a higher concentration at the top where oxygen is most abundant.

Final Answer