Cells are microscopic in size, requiring microscopes for visualization .
About 10 human cells could be stacked on top of one another in the thickness of a piece of paper. Human red blood cells are about 7.5 micrometers wide, and are about 5-100 times as large as a bacterial cell. The female egg cell , located in the ovary, is the largest cell in the human body. There is no typical cell shape . The study of bacteria is bacteriology, part of the science of microbiology .