Saylor.org's Cell Biology/Cellular Transport
Just as your body has a circulatory system that moves nutrients and waste, every cell in your body has a vast network system that carries things from one place to another. In Unit 5, you learned about the units that make up this transport network. You will now learn about the signals and “roadmaps” that direct traffic in that network. Though there are many different types of transport, the most important ones export gene products from the nucleus to their destined locations. As you will see, the gene products themselves include specific sequences that define their destination.
You will also learn that cells have the ability to secrete or intake vesicles (membrane-enclosed spaces), which also require specific transport mechanisms. This unit will go over a few of the major ones.