tailieunhanh - Lecture Human anatomy and physiology - Chapter 3: Cells (part b)

Chapter 3 - Cells: The living units (part b). The main contents of this chapter include all of the following: Membrane transport: active processes, active transport, primary active transport, secondary active transport, vesicular transport, endocytosis and transcytosis,.and other contents. | Cells: The Living Units: Part B Two types of active processes: Active transport Vesicular transport Both use ATP to move solutes across a living plasma membrane Requires carrier proteins (solute pumps) Moves solutes against a concentration gradient Types of active transport: Primary active transport Secondary active transport Energy from hydrolysis of ATP causes shape change in transport protein so that bound solutes (ions) are “pumped” across the membrane Sodium-potassium pump (Na+-K+ ATPase) Located in all plasma membranes Involved in primary and secondary active transport of nutrients and ions Maintains electrochemical gradients essential for functions of muscle and nerve tissues Figure Extracellular fluid K+ is released from the pump protein and Na+ sites are ready to bind Na+ again. The cycle repeats. Binding of Na+ promotes phosphorylation of the protein by ATP. Cytoplasmic Na+ binds to pump protein. Na+ Na+-K+ pump K+ released ATP-binding site Na+ bound Cytoplasm ATP ADP P K+ K+ binding triggers release of the phosphate. Pump protein returns to its original conformation. Phosphorylation causes the protein to change shape, expelling Na+ to the outside. Extracellular K+ binds to pump protein. Na+ released K+ bound P K+ P Pi 1 2 3 4 5 6 Figure step 1 Extracellular fluid Cytoplasmic Na+ binds to pump protein. Na+ Na+-K+ pump ATP-binding site Cytoplasm K+ 1 Figure step 2 Binding of Na+ promotes phosphorylation of the protein by ATP. Na+ bound ATP ADP P 2 Figure step 3 Phosphorylation causes the protein to change shape, expelling Na+ to the outside. Na+ released P 3 Figure step 4 Extracellular K+ binds to pump protein. P K+ 4 Figure step 5 K+ binding triggers release of the phosphate. Pump protein returns to its original conformation. K+ bound Pi 5 Figure step 6 K+ is released from the pump protein and Na+ sites are ready to bind Na+ again. The cycle repeats. K+ released 6 Figure Extracellular fluid K+ is released from the . | Cells: The Living Units: Part B Two types of active processes: Active transport Vesicular transport Both use ATP to move solutes across a living plasma membrane Requires carrier proteins (solute pumps) Moves solutes against a concentration gradient Types of active transport: Primary active transport Secondary active transport Energy from hydrolysis of ATP causes shape change in transport protein so that bound solutes (ions) are “pumped” across the membrane Sodium-potassium pump (Na+-K+ ATPase) Located in all plasma membranes Involved in primary and secondary active transport of nutrients and ions Maintains electrochemical gradients essential for functions of muscle and nerve tissues Figure Extracellular fluid K+ is released from the pump protein and Na+ sites are ready to bind Na+ again. The cycle repeats. Binding of Na+ promotes phosphorylation of the protein by ATP. Cytoplasmic Na+ binds to pump protein. Na+ Na+-K+ pump K+ released ATP-binding site Na+ bound Cytoplasm ATP ADP P