1 / 28

Membrane Dynamics

Membrane Dynamics. 5. About this Chapter. Mass balance and homeostasis Diffusion Protein-mediated, vesicular, and transepithelial transport Osmosis and tonicity The resting membrane potential Insulin secretion. Mass Balance in the Body. Figure 5-2. Mass Balance and Homeostasis.

teigra
Download Presentation

Membrane Dynamics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Membrane Dynamics 5

  2. About this Chapter • Mass balance and homeostasis • Diffusion • Protein-mediated, vesicular, and transepithelial transport • Osmosis and tonicity • The resting membrane potential • Insulin secretion

  3. Mass Balance in the Body Figure 5-2

  4. Mass Balance and Homeostasis • Clearance • Rate at which a molecule disappears from the body • Mass flow = concentration  volume flow • Homeostasis  equilibrium • Osmotic equilibrium • Chemical disequilibrium • Electrical disequilibrium

  5. Homeostasis Distribution of solutes in the body fluid compartments The compartments in the body are in a state of chemical disequilibrium Figure 5-3a

  6. Homeostasis Figure 5-3b

  7. Diffusion Map of membrane transport Membranes are selectively permeable Figure 5-4

  8. Diffusion: Seven Proprieties • Passive process • High concentration to low concentration • Net movement until concentration is equal • Rapid over short distances • Directly related to temperature • Inversely related to molecular size • In open system or across a partition

  9. Simple Diffusion Fick’s law of diffusion Figure 5-6

  10. Membrane Proteins Function • Structural proteins • Enzymes • Membrane receptor proteins • Transporters • Channel proteins • Carrier proteins

  11. Membrane Transport Proteins Water channels and ion channels are examples of open channels Figure 5-9a

  12. Membrane Transport Proteins Figure 5-9b

  13. Gating of Channel Proteins Gated channels are either chemically gated or voltage-gated channels Figure 5-11

  14. Types of Carrier-Mediated Transport Figure 5-12a

  15. Types of Carrier-Mediated Transport Figure 5-12b

  16. Types of Carrier-Mediated Transport Carrier proteins never create a continuous passageway Figure 5-12c

  17. Facilitated Diffusion Diffusion of glucose into cell • How is the concentration gradient maintained for glucose? Figure 5-15

  18. Primary Active Transport ECF 1 ATP ADP 5 2 3 Na+ from ICF bind ICF P ATPase is phosphorylated with Pi from ATP. 2 K+ released into ICF Protein changes conformation. Protein changes conformation. P 3 K+ released into ICF 4 3 2 K+ from ECF bind P P Mechanism of the Na+-K+-ATPase ATP is used as an energy source Figure 5-17

  19. Primary Active Transport ECF 1 3 Na+ from ICF bind ICF Figure 5-17, step 1

  20. Primary Active Transport ECF 1 ATP ADP 2 3 Na+ from ICF bind ICF P ATPase is phosphorylated with Pi from ATP. Figure 5-17, steps 1–2

  21. Primary Active Transport ECF 1 ATP ADP 2 3 Na+ from ICF bind ICF P ATPase is phosphorylated with Pi from ATP. Protein changes conformation. 3 K+ released into ICF 3 P Figure 5-17, steps 1–3

  22. Primary Active Transport ECF 1 ATP ADP 2 3 Na+ from ICF bind ICF P ATPase is phosphorylated with Pi from ATP. Protein changes conformation. 3 K+ released into ICF 4 3 2 K+ from ECF bind P P Figure 5-17, steps 1–4

  23. Primary Active Transport ECF 1 ATP ADP 5 2 3 Na+ from ICF bind ICF P ATPase is phosphorylated with Pi from ATP. 2 K+ released into ICF Protein changes conformation. Protein changes conformation. P 3 K+ released into ICF 4 3 2 K+ from ECF bind P P Figure 5-17, steps 1–5

  24. Secondary Active Transport 1 Na+ binds to carrier. 3 Glucose binding changes carrier conformation. Intracellular fluid Lumen of intestine or kidney Na+ Na+ SGLT protein Glu Glu [Na+] high [Glucose] low [Na+] low [Glucose] high Na+ released into cytosol. Glucose follows. 4 2 Na+ binding creates a site for glucose. Na+ Na+ Glu Glu Mechanism of the SGLT Transporter Figure 5-18

  25. Secondary Active Transport 1 Na+ binds to carrier. Intracellular fluid Lumen of intestine or kidney Na+ SGLT protein Glu [Na+] high [Glucose] low [Na+] low [Glucose] high Figure 5-18, step 1

  26. Secondary Active Transport 1 Na+ binds to carrier. Intracellular fluid Lumen of intestine or kidney Na+ SGLT protein Glu [Na+] high [Glucose] low [Na+] low [Glucose] high 2 Na+ binding creates a site for glucose. Na+ Glu Figure 5-18, steps 1–2

  27. Secondary Active Transport 1 Na+ binds to carrier. 3 Glucose binding changes carrier conformation. Intracellular fluid Lumen of intestine or kidney Na+ Na+ SGLT protein Glu Glu [Na+] high [Glucose] low [Na+] low [Glucose] high 2 Na+ binding creates a site for glucose. Na+ Glu Uses the energy of one molecule moving down its concentration gradient Figure 5-18, steps 1–3

  28. Secondary Active Transport 1 Na+ binds to carrier. 3 Glucose binding changes carrier conformation. Intracellular fluid Lumen of intestine or kidney Na+ Na+ SGLT protein Glu Glu [Na+] high [Glucose] low [Na+] low [Glucose] high Na+ released into cytosol. Glucose follows. 4 2 Na+ binding creates a site for glucose. Na+ Na+ Glu Glu Figure 5-18, steps 1–4

More Related