Wisconsin Esthetics State Board Practice Test

What is the most common form of bacterial cells, shaped like rods?

1. Diplococci

2. Spirilla

3. Bacilli

4. Streptococci

The correct answer is: Bacilli

The most common form of bacterial cells that is shaped like rods is bacilli. Bacilli are characterized by their elongated, cylindrical shape, resembling that of a rod. This shape is significant in microbiology as it helps in the classification and identification of bacterial species. Understanding bacterial morphology is essential for various applications, including clinical diagnosis, as different shapes can indicate different types of bacteria with distinct characteristics. Bacilli have a wide range of species within their category, some of which can be harmless while others can cause illness. On the other hand, options like diplococci refer to spherical bacteria arranged in pairs, spirilla indicate spiral-shaped bacteria, and streptococci are spherical bacteria that form chains. Each of these shapes has unique implications for how the bacteria function and behave, but for the specific question regarding rod-shaped bacteria, bacilli is the correct choice.