This document provides an overview of the cell theory and the development of cell biology. It begins by distinguishing between prokaryotic and eukaryotic cells based on their features. Next, it discusses the development of microscopy from the 16th century onwards and key contributors to the cell theory, including Hooke, Schleiden, Schwann, Remak, and Virchow. It then outlines the classical and modern cell theories. The rest of the document describes characteristics of prokaryotic and eukaryotic cells in more detail and provides examples of organelles and activities for students to learn about cell structures.