341lecture20oct26sakai

341lecture20oct26sakai - Cell Biology 341 Last lecture:...

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Cell Biology 341 Monday, October 26, 2009 Today: Exam 2 from fall 08 is on Sakai See the videos on your DVD for chapters 10 and 11 Ion channels carry out passive transport They are highly selective for a particular ion K + leak channels create a membrane potential across the plasma membrane Last lecture: chapter 11 Ion gradients: Na + is higher in concentration outside animal cells; K + is higher in concentration in the cytosol active transport: Coupled transporters ( symports and antiports ) couple the movement of a molecule against its gradient to the movement of an ion down its concentration gradient The Na + -K + pump is phosphorylated using a phosphate from ATP as it transports 3 Na + out and 2 K + into the cell, both against their gradients Epithelial cells of the gut contain an apical Na + -driven glucose symport that actively transports glucose into the cell from the gut, and a basal glucose uniport that passively transports glucose out of the cell
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Example of a glucose-Na + symport in the epithelial cells of the gut A passive glucose uniport (figure 11-5) in the basal domain releases glucose to other tissues In the apical domain, a the concentration of glucose is higher inside the cell than in the gut This is active transport Active transport Figure 11-11
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More active transport symports and pumps Other Na + -symports in the gut, kidney and other tissues transport amino acids and sugars into cells by coupled transport
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This note was uploaded on 12/05/2009 for the course BIO 341 taught by Professor Noris during the Fall '09 term at Rhode Island.

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341lecture20oct26sakai - Cell Biology 341 Last lecture:...

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