《物质的跨膜运输》.ppt

D. Transport processes within an eukaryotic cell 3. Active transport: Carrier protein-mediated movement up the gradient B. Cells carry out active transport in three main ways C. Direct active transport depends on four types of transport ATPases 4. Indirect active transport is driven by Ion gradients ----- Cotransport The difference between animal and plant cells to absorb nutrients B. Cotransport: Symport and antiport 5. Endocytosis:  Large molecules enter into cells A. Endocytosis imports extracellular molecules dissolved or suspended in fluid by forming vesicles from the plasma membrane B. Phagocytosis: The uptake of large particles C. Receptor-mediated endocytosis Chapter 5 B. Cell Signaling 1. Overview of cell signaling A. Some of the basic characteristics of cell signaling B. The forms of cell communication----- Different types of chemical signals can be received by cells C. Signal Molecules and Receptors Receptors include three classes: glycoproteins D. Two types of intracellular signaling proteins that act as Molecular Switches 2. Signal transdution mediated by  the receptors within cells A. Some small hydrophobic hormones (steroid hormones) whose receprors are intracellular gene regulatory proteins. B. Nitric oxide couples G protein-linked receptor stimulation in endothelial cells to relaxation of smooth muscle cells in blood vessels The action of Nitric oxide on blood vessels The mechanism by which acetylcholine stimulation of the endothelial cells leads to smooth muscle relaxation also explains the mechanism of action of the chemical nitroglycerin. The drug sildenafil, sold under the trade name Viagra, is an inhibitor of a cyclic GMP-specific phosphodiesterase that normally catalyzes the breakdown of cyclic GMP. 3. Signal transduction mediated by  the receptors on the cell surface A. Mediated by the Ion-Linked Receptors which convert chemical signals into electrical ones B. Signal transduction mediated by G protein-li