Biology > EXAM REVIEW > Chapter 12: Membrane Transport Southern Methodist University - BIOLOGY SS07chapter 12 (All)

Chapter 12: Membrane Transport Southern Methodist University - BIOLOGY SS07chapter 12

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Reghunathan, Saranya Cell Biology SS07 Exam 1 Chapter 12: Membrane Transport I. Membran e Transport a. Small hydrophobic molecules and small uncharged polar molecules can diffuse freely across t ... he lipid bilayer i. Large uncharged polar molecules, ions cannot b. Special transport proteins accomplish transport of molecules which do not diffuse across lipid bilayers i. Highly specific- lock and key fit ii. Two classes of proteins: carrier proteins and channel proteins 1. carrier proteins a. turnstile, revolving door b. change conformation and binding sites c. similar to enzymes d. shift small molecules by changing its shape e. allows passage of molecules that fit on binding site f. can do both passive and active transport g. active transport is produced in 3 ways: i. coupled transporter- cotransportation; more than one time of molecule at a time; one against gradient and one with gradient ii. ATP-driven pump: uphill transport coupled with hydrolysis of ATP 1. Na+/K+ ATPase: uses energy of ATP hydrolysis to pump K+ into cell and Na + out of cell a. Resultant gradient of Na+ can be used to drive the transport of a second molecule against its gradient i. Symport: move in same direction as Na ii. Antiport: moves in opposite direction of N [Show More]

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