[BIO 211] - Midterm Exam Guide - Ultimate 42 pages long Study Guide!

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Cells eat, communicate, and respond to environmental changes: must change the composition of their plasma membrane and internal compartments to do this. Exocytosis- delivers newly synthesized proteins, carbohydrates, and lipids to the plasma membrane or extracellular space. Endocytosis- removes components of the plasma membrane to deliver them to internal compartments endosomes- where recycling or degradation occurs. This process can also be used to trap nutrients where they will then be taken up by macromolecules. Lumen of membrane enclosed compartments allows proteins to travel in this space without having to cross a membrane: forms from the donor compartment. Transport proteins continuously bud off from one membrane to fuse with another in all eukaryotic cells: cargo- membrane components or lumen soluble molecules are transported during this process, transport proteins must be selective. Secretory pathway- leads from the er to the golgi and cell surface: alternative pathway leads to lysosomes.