Arizona Esthetics State Board Practice Exam

Bacilli and spirilla are able to move themselves using hair-like projections known as:

1. Cilia

2. Flagella

3. Pseudopodia

4. Microvilli

The correct answer is: Flagella

Bacilli and spirilla are types of bacteria that possess the ability to move independently, and this movement is facilitated by structures called flagella. Flagella are long, whip-like appendages that rotate or wave to propel the bacteria through their environment, enabling them to navigate towards favorable conditions such as nutrients or away from harmful substances. Understanding the specific function of flagella is essential because it highlights how these microorganisms adapt to their surroundings and demonstrate mobility, which can be critical for their survival and pathogenicity. The other structures mentioned, such as cilia, pseudopodia, and microvilli, have distinct functions in different contexts. Cilia are short and numerous, mainly aiding in the movement of fluids and particles across cell surfaces, while pseudopodia are extensions of a cell's cytoplasm used for movement and feeding in some protozoa. Microvilli, on the other hand, are small projections that increase surface area for absorption, primarily found on the surface of epithelial cells. Thus, the recognition that flagella facilitate motility in bacilli and spirilla is key to understanding their behavior in various environments.