Who observed the first bacterial cell?

Anton von Leeuwenhoek, a Dutch scientist, was the first person to observe a living cell through a microscope. He used a simple microscope that he designed himself to observe bacteria, which he called "animalcules," in a drop of water. 

Robert Hooke, an English scientist, was the first person to observe cells, but his observations were of dead plant cells using a compound microscope. Louis Pasteur is known for his work in microbiology, including the germ theory of disease, and Joseph Lister is known for his contributions to antiseptic surgery.