Arkansas Esthetician Practice Exam

Bacilli are rod-shaped bacterial cells, while cocci are spherical, spirilla are spiral-shaped, and vibrios are comma-shaped. Bacilli are the most common form of bacterial cells, comprising about 50% of all bacterial species. This is because their shape allows them to reproduce quickly and efficiently, making them more adaptable to different environments. Cocci are less common, making up about 30% of bacterial species. Spirilla and vibrios are even less common, making up about 10% and 1% of bacterial species, respectively. Therefore, bacilli are the most common form of bacterial cells.