The cell theory is a unifying biological concept. All life on Earth exists as cells. These have basic features in common. Differences between cells are due to the addition of extra features. This provides indirect evidence for evolution.

All cells arise from other cells, by binary fission in prokaryotic cells and by mitosis and meiosis in eukaryotic cells.

At GCSE, you only needed to know about the membrane, cytoplasm, nucleus, chloroplast, vacuole and ribosomes...in this chapter you will get a better insight into how intricate and busy a cell really is! 

You have to be able to recognise cell organelles from both diagrams and electronmicrographs and then apply your knowledge of these features in explaining adaptations of eukaryotic cells.