Bio 333 chapter 11 guide

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Name__Trinity Rude__ BIO-333 Chapter 11 Guide 1. (pgs. 637-639, figs. 11-1 and 11-2, Table 11-1) Using Table 1, identify which molecular components have higher concentrations on the cytoplasmic side vs. the extracellular side of the plasma membrane. Using figure 11-1 and 11-2, identify the rates of diffusion across a lipid bilayer for each group of components. The concentration of Na + and Cl- are higher outside than inside the cell, whereas the concentration of K+ is higher inside than out. In general, the smaller the molecule and the more hydrophobic or nonpolar is it the more easily it will diffuse cross a lipid bilayer. Small uncharged nonpolar molecules diffuse slower. 2. (pgs. 638-640, fig. 11-3) What is the function of membrane transport proteins? Define transporters and channels. Define active and passive transport. The function of a membrane transport proteins are special proteins that are specialized to mediate the passage of molecules across the membrane. The two main classes are transporters and channels. To move a particular solute across a membrane, the transporters bind to it and then go through a sequence of conformational changes that alternately reveal solute-binding sites on one side of the membrane and then on the other side. However, channels interreact tightly with the solute to be transported much weaker. They will form continuous pores that extend across the bilayer. 3. (pgs. 639-640, fig. 11-4) Describe concentration gradient and membrane potential. How do these two phenomena influence the electrochemical gradient? Concentration Gradient: occurs when the concentration of particles is higher in one area over another (plasma membrane) Membrane Potential: is a potential gradient that forces ions to passively more in one direction- positive ions are attracted to negative, where the negative is attracted to the positive side. 4. (pgs. 640-641, figs. 11-5 and 11-6) Describe the process by which transporters go through a conformational change (during passive transport) while moving solute from one side of the membrane to the other. Compare the rates of diffusion for transporter-mediated diffusion and channel-mediated diffusion. Carrier proteins bind specific solutes and transfer them across the lipid bilayer by undergoing conformational changes that expose the solute-binding site sequentially on one side of the membrane and then on the other side. 5. (pgs. 641-642, figs. 11-7 and 11-8) Describe the three general ways active transport links a transporter to an energy source. Define uniport, symporter, and antiporter. Define secondary active transport and primary active transport . Three different ways of driving active transport, coupled transport, ATP driven pumps, and light orredox driven pumps. Coupled transporters tackle the energy put away in concentration gradient to couple the difficult uphill of one solute across the film to the declining transport of another. ATP driven pumps couple uphill transport to the hydrolysis of ATP. Light or redox driven pumps, which are known in microorganisms, archaea, mitochondria, and chloroplasts, couple uphill transport to a contribution of energy from light. A few transporters basically latently intervene the development of a solitary solute from one side of the layer to the next at not entirely set in stone by their Vmax and Km, they are called uniporters. Coupled transport includes either the concurrent exchange of a second solute in a similar heading, performed by symporters, or the exchange of a second solute the other way, performed by

antiporters. Essential active transport is the vehicle of particles against a fixation inclination by the utilization of energy from ATP. In the optional active transport, the energy is gotten optionally from energy that has been put away as ionic fixation contrasts between the different sides of the membrane. 6. (pgs. 642-643, fig. 11-9) Describe the process of glucose transport shown in figure 11-9. Why is this process called cooperative? Which components are moving up/down its concentration gradient? Since the Na concentration is much higher in the extracellular space than in the cytosol, glucose is more likely to bind to the transporter in the outward facing state. The transition occurs only when both Na and glucose are bound. Glucose dissociation is likewise enhanced when Na is lost, because of cooperativity in binding of the 2 solutes. The results, the net transport of both Na and Glucose into the cell. 7. (pgs. 643-644, fig. 11-10) Describe the general structure of a transporter. What is an inverted repeat? Why is this conformation called pseudosymmetric? Transporters are regularly worked from heaps of at least 10 Alpha helices that length the layer. Like enzymes, transporters can work in the opposite direction, the inverted repeats are the pressing of the transmembrane Alpha helices in one portion of the helix group is primarily like the pressing in the other half, yet the two parts are altered in the layer comparative with one another. Pseudo Symmetric, is the point at which the paths open and close on one or the other side of the layer have intently comparative calculations, permitting alternating access to the particle and solute-restricting locales in the middle. 8. (pgs. 645-646, fig. 11-11) Describe the transcellular transport of glucose that occurs across intestinal epithelial cells. In cells that retain supplements in the stomach, they add to the transcellular transport. Solutes are moved across the epithelial cell layer into the extracellular liquid from where they pass into the blood. Glucose is pushed into the cell through a glucose uniporter in the basal and horizontal film spaces, which keeps the inward concentration of Na lower. Neighboring cells are utilizing tight intersections permitting a focus inclination of glucose to be kept up with across the cell sheet. 9. (pg. 646, fig. 11-12) Describe the three types of ATP-driven pumps. What is unique about the V-type pumps? The three sorts of ATP driven pumps are the P type pumps, ABC transporters, and V sort pumps. P type pumps are functionally and structurally related multipass transmembrane proteins. They are called P type since they phosphorylate themselves during the pumping cycle. ABC transporters contrast structurally from P type ATPases and fundamentally pump little atoms across cell layers. V sort pumps are turbine-like protein machines, built from numerous various subunits. The V kind proton pump transfers H into organelles like lysosomes, synaptic vesicles, and plant or yeast vacuoles, to ferment the inside of these organelles. They are likewise connected with ATP synthase because they work backward. 10. (pgs. 647-648, figs. 11-13 and 11-14) Describe the concentration gradient of Ca 2+ in cells. What is the function of the SR Ca 2+ pump? Describe the pumping cycle of the SR Ca 2+ pump at the molecular level. Ca has exceptionally low concentration in their cytosol, however a high extracellular concentration. The flow of Ca down its lofty concentration gradient because of extracellular signs is one method for sending these signs quickly across the plasma membrane. Ca2+ transporters that effectively pump Ca2+ out of the cell assist with keeping up with the gradient.

The SR is a particular kind of endoplasmic reticulum that shapes an organization of rounded sacs in the muscle cell cytoplasm, and it fills in as an intracellular store of Ca2+ 11. (pgs. 648-649, fig. 11-15) Describe the function of a NA + -K + pump. Are these ions moving against their chemical gradient? Are these ions moving against their electrical gradient? Does this ion movement contribute to the membrane potential? The SP (sodium potassium) pump acts to transport sodium and potassium ions across the cell membrane in a ration of 3 sodium ions out of every 2 potassium ions brought in. They are moving against their chemical and electrical gradient. 12. (pgs. 649-650, figs. 11-16, 11-17, and 11-18) Describe the structure and function of an ABC transporter. What is MDR and why do ABC transporters have clinical relevance? 13. (pgs. 651-652) Are ion channels selective or can any ion pass through them? Is diffusion through channels faster than through transporters? Is diffusion through channels passive, active, or can be either? Ion channels are highly selective pores that open and close rapidly. Yes, the diffusion through channels is way faster than transporters. Diffusion is passive 14. (pgs. 652-653, figs. 11-19 and 11-20) Describe the osmotic gradient found in eukaryotic cells - what characteristics contribute to this gradient? Describe the structure and function of aquaporins. How are H 3 O + molecules excluded from passing through these structures? These cells have a high concentration of solutes making and osmotic gradient, in view of this the osmotic power will "pull" water into the cell, making it expand. Aquaporins are embedded in their plasma membrane to permit water to move more quickly, while obstructing the entry of ions. The have thin pore that permits water atoms to cross the layer in single file. These channels are impermeable to H, which fundamentally present in cells as H3O. These particles diffuse through water quickly, utilizing a sub-atomic transfer instrument that requires the making and breaking of hydrogen bonds. Since the aquaporins contain 2 asparagine (assist with separating poisonous smelling salts inside cells), which tie to the oxygen iota of the focal water particle forcing a bipolarity on the whole section of water particles. This makes it unimaginable for the making and breaking of hydrogen bonds. Meaning it will be impermeable to H 15. (pgs. 653-654, figs. 11-21 and 11-22) Describe the basic structure of an ion channel. Describe the four basic types of these channels. They have small pores, to have the option to place ions into cozy contact with the walls of the channel so only ions of suitable size and charge can pass. Particle channels are not generally open, as aquaporins. All things being equal, they are gated, which permits them to open and close. The 4 fundamental sorts incorporate voltage gated, ligand gated extracellular, ligand gated intracellular, and precisely gated channel 16. (pg. 655) Explain how K + leak channels contribute to the membrane potential. They make the plasma membrane much more preamble to K, rather than other ions, they have a crucial role in maintaining the membrane potential across all plasma membranes. 17. (655 and 657, fig. 11-23) Aside from Na+-K+ pumps and K+ leak channels, what else influences the membrane potential? What is the range for the resting membrane potential of a typical animal cell? Electrogenic H pumps in the mitochondrial internal membrane, produce the greater part of the membrane potential. K comes nearly to equilibrium, where an electrical power applied by

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