Assume you inoculated 100 facultatively anaerobic cells onto nutrient agar and incubated the plate aerobically. You then inoculated 100 cells of the same species onto nutrient agar and incubated the second plate anaerobically. After incubation for 24 hours, you should have
a. more colonies on the aerobic plate.
b. more colonies on the anaerobic plate.
c. the same number of colonies on both plates.

Verified step by step guidance

1. Understand the definition of facultatively anaerobic organisms: These organisms can grow in both the presence and absence of oxygen.
2. Consider the growth conditions: The first plate is incubated aerobically (with oxygen), and the second plate is incubated anaerobically (without oxygen).
3. Recall that facultatively anaerobic organisms can utilize oxygen for growth when it is available, but can also switch to anaerobic metabolism when oxygen is absent.
4. Analyze the growth potential: Since facultatively anaerobic organisms can grow in both conditions, they should be able to form colonies on both plates.
5. Conclude that the number of colonies should be the same on both plates, assuming all other conditions are equal and no other factors affect growth.

Key Concepts

Facultative Anaerobes

Facultative anaerobes are microorganisms that can grow in both the presence and absence of oxygen. They prefer aerobic respiration when oxygen is available, as it yields more energy, but can switch to fermentation or anaerobic respiration when oxygen is scarce. Understanding this adaptability is crucial for predicting their growth patterns under different oxygen conditions.

Nutrient Agar

Nutrient agar is a common growth medium used in microbiology to culture a wide variety of microorganisms. It provides essential nutrients, including peptones and agar, which support the growth of bacteria. The composition of nutrient agar allows for the cultivation of both aerobic and anaerobic bacteria, making it suitable for experiments involving different oxygen environments.

Aerobic vs. Anaerobic Conditions

Aerobic conditions refer to environments where oxygen is present, promoting the growth of organisms that require oxygen for respiration. In contrast, anaerobic conditions lack oxygen, favoring the growth of organisms that thrive in its absence. The growth outcomes on the two plates in the experiment will depend on the oxygen requirements of the facultative anaerobes, influencing the number of colonies formed.