Membranes Transport Lehninger Readings Chapter 11 pages 389 413 At the end of this section you should be able to explain how proteins make biological membranes selectively permeable Given relevant characteristics of a transporter you should be able to classify the transporter discuss its likely biological functions describe its general structure and explain the mechanisms by which this structure allows it to carry out its function Student Learning Objectives You should be able to 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 3 Tell the Big Picture story of why membrane transport is needed and how it happens Describe the forces that can drive simple diffusion and facilitated diffusion List the sodium potassium calcium and proton gradients found across membranes Compare and contrast simple diffusion and facilitated diffusion Compare and contrast facilitated diffusion with enzyme catalysis Based on the characteristics of a real or hypothetical transporter classify the transporter using the various classification schemes described in class Explain the need for active transport in cells Compare and contrast active transport and facilitated diffusion Discuss the properties of carriers and channels and recognize examples of each from descriptions of the transporter s properties Identify a transporter as a uniporter symporter or antiporter based on information about the transporter Describe the GLUT family of transporters and explain their function based on general principles of transport Compare the three types of ATP driven transports including their general structures and mechanisms and give examples of each Describe two common sources of energy for secondary active transport and give examples of transporters that use each Explain the name secondary active transport in terms of energetics Compare and contrast the sources of energy used for active transport Explain the relationship between primary active transport and secondary active transport and predict how perturbations of in one aspect of cellular transport alters other aspects of transport List the sodium potassium calcium and proton gradients found across membranes Gradients you should know H across mitochondrial membranes H across bacterial plasma membranes Na across animal plasma membranes K across animal plasma membranes Ca2 across ER SR and plasma membranes Page 1 Membrane Transport 1 Tell the Big Picture story of why membrane transport is needed and how it happens Membranes as Selectivelypermeable Barriers Figure 1 7 Cystic Fibrosis Page 415 2 3 4 Describe the forces that can drive simple diffusion and facilitated diffusion Compare and contrast simple diffusion and facilitated diffusion Compare and contrast facilitated diffusion with enzyme catalysis Energetics Activation Barrier Electrochemical Potential Figure 11 28 Page 2 Membrane Transport 5 Based on the characteristics of a real or hypothetical transporter classify the transporter using the various classification schemes described in class Figure 11 26 Methods of Classifying Membrane Transporters Based on Structural Similarity Based on Energetics Passive Simple Diffusion Facilitated Diffusion Ion Channels Page 3 Membrane Transport 6 7 Explain the need for active transport in cells Compare and contrast active transport and facilitated diffusion Methods of Classifying Membrane Transporters Based on Energetics Active Primary Figure 11 35 8 3 types Discuss the properties of carriers and channels and recognize examples of each from descriptions of the transporter s properties Secondary Based on Transport Properties Channels Figure 11 26 9 Identify a transporter as a uniporter symporter or antiporter based on information about the transporter Carriers Based on Solute and Direction of Movement Uniport Figure 11 34 Page 4 Membrane Transport 10 Describe the GLUT family of transporters and explain their function based on general principles of transport Example the GLUT family of transporters Function Structure Figure 11 30 Mechanism Figure 11 32 Kinetics Figure 11 31 Page 5 Membrane Transport 11 Compare the three types of ATP driven transports including their general structures and mechanisms and give examples of each 3 types of Primary Active Transport P type active transport Structure Transmembrane domain A transfers movement N binds NTP P phosphorolaytionsite Asp Figure 11 36 Mechanism Figure 11 37 Page 6 Membrane Transport P type Continued Example Na K ATPase Na and K ions are moved against electrochemical gradients In neurons this is the basis for action potentials Figure 11 38 This gradient provides the energy for many but not all secondary active transporters in animals F type and V type ATPase Figure 11 39 Structure Function Figure 11 40 ABC transporters Page 7 Membrane Transport 12 Describe two common sources of energy for secondary active transport and give examples of transporters that use each 13 Explain the name secondary active transport in terms of energetics Secondary Active Transport Lactose Permease Function Energy source Figure 11 41 Classification Na Glucose Symporter Function Movement of Na is negative Delta G coupled with glucose Figure 11 43 which is positive moves them into the cell 14 Compare and contrast the sources of energy used for active transport 15 Explain the relationship between primary active transport and secondary active transport and Energy Source predict how perturbations of in one aspect of cellular transport alters other aspects of transport Page 8