So let's talk about cells for a bit. All living things are made of one or more cells. Everything we know about that has the properties of life we talked about in the first lecture consist of cells. The chemical reactions of life take place within cells. All of the properties of life occur within cells.
All cells come from pre-existing cells.
New cells come from the division of old cells. Cells whose DNA has no envelope around it Cells whose DNA has an envelope. Cells with a nuclear envelope are called eukaryotic cells. The cytoplasm of eukaryotic cells is also more complex than that of prokaryotic cells. Eukaryotic cells are also much larger than prokaryotic cells.