This document discusses cell structure and function. It begins by explaining that cells are the basic units of life and outlines the three main points of the cell theory. It then describes several types of microscopes that have enabled scientists to explore the internal structures of cells, such as electrons microscopes, confocal light microscopes, and scanning probe microscopes. The rest of the document details the structures and organelles found within plant and animal cells, including the nucleus, cytoplasm, mitochondria, chloroplasts, cell membrane, cell wall, and how diffusion and osmosis allow for movement of molecules across cell boundaries.