What shape do cocci bacteria have?

Cocci bacteria are characterized by their spherical shape, which distinguishes them from other bacterial forms. This spherical morphology allows for greater surface area-to-volume ratio, which can be beneficial for nutrient absorption and the overall metabolic activity of the cells. Cocci can appear singularly, in pairs (diplococci), chains (streptococci), or clusters (staphylococci), but regardless of their arrangement, their defining characteristic remains their round shape.

In contrast, rod-shaped bacteria, known as bacilli, are elongated and cylindrical, while spiral bacteria are curved or helical in shape. Filamentous bacteria have long, thread-like forms, which further differentiates them from cocci. Understanding the morphology of bacteria is essential for microbiological identification and classification, which is foundational in fields such as clinical microbiology and infectious disease.