Final answer:
The term 'vibrio' refers to a prokaryotic cell that is comma-shaped, which sets it apart from cocci, spirilli, and bacilli cells. The correct answer is option d).
Step-by-step explanation:
The term prokaryotes refers to unicellular organisms that lack a true nucleus and membrane-bound organelles. Based on shape, prokaryotic cells are categorized into three basic groups: cocci, which are spherical; spirilli, which are spiral-shaped; and bacilli, which are rod-shaped. However, the question asks specifically about a prokaryotic cell that is comma-shaped.
The correct answer to this question is vibrio, which refers to a prokaryotic cell with a characteristic comma shape. While all prokaryotes share certain structures such as a cell wall and plasma membrane, their shapes can greatly vary and are key identifiers for classification purposes.
Cocci are recognizable by their round shape, often appearing like balls or spheres. Bacilli are identifiable by their elongated rod-like structure, whereas spirilli have a more rigid spiral form. Vibrio falls under the category of curved bacteria and is distinctly comma-shaped, differentiating it from the other shapes mentioned.