Plant Cell Picture: Plant Cell Wall showing Cellulose Synthesis; this image is 500 pixels across the original is 4,000 pixels across.
The image above shows a plant cell plasma membrane (greenish layer) with underlying cortical microtubules (purplish grey). Moving within the plasma membrane, are rosettes (blue green) containing the enzyme cellulose synthetase. These rosettes move through the membrane, being directed in some fashion by the underlying cortical microtubules (there may also be some influence operating in the opposite diretion i.e. from cellulose to microtubule). Issuing from the rosettes are cellulose molecules (36 per rosette) which stream out behind the rosettes (straw coloured). These cellulose molecules aggregate forming microfibrils of about 5nm diameter, although they may later aggregate further to make thicker fibres. Cellulose microfibrils are shown above and the microfibrils are cross linked by hemicelluloses.