TRANSPORT ACROSS CELL MEMBRANE

1. TRANSPORT ACROSS CELL MEMBRANE

2. Specific learning objectives At the end of the class You must know.......... • Define transport • Name the common ion channel in the cell membrane. • Name the different type of carrier protein with example. • Classify the transport process. • List the different between passive and active transport. • Explain the types of passive transport mechanism.

3. The key organelle involved with cell transport is the “CELL MEMBRANE”

4. Cell membranes are made of PHOSPHOLIPIDs • HYDROPHILIC heads (water liking)-Attracted to the water • called POLAR • HYDROPHOBIC tails (water fearing)-Not attracted to the water • called NON-POLAR

5. Types of Cellular Transport • Passive Transport • Active Transport • Vesicular Transport • Transport across the epithelia

6. PASSIVE TRANSPORT • Cell uses no energy • molecules move randomly • Molecules move from an area of high concentration to an area of low concentration. • (HighLow)

7. Weeee!!! high low Passive Transport cell doesn’t use energy • Diffusion • Facilitated Diffusion • Osmosis

8. Diffusion: random movement of molecule from an area ofhighconcentration to an area oflowconcentration. 2. Diffusion continues until all molecules are evenly spaced (equilibrium is reached)

9. Diffusion through a membrane Cell membrane Outside cell Inside cell

10. Diffusion through a membrane Cell membrane Diffusion Outside cell Inside cell

11. What determines the rate of diffusion?

12. 1. concentration gradient. Largerthe concentration difference between the two sides of the membrane the faster the rate of diffusion. 2.Temperature. Higher temperatures give molecules or ions more kinetic energy. Molecules move faster, so diffusion is faster.

13. 3. The surface area. The greater the surface area the faster the diffusion can take place. This is because the more molecules or ions can cross the membrane at any one moment. 4. The type of molecule or ion diffusing. Large molecules need more energy to get them to move so they tend to diffuse more slowly. Non-polar molecules diffuse more easily than polar molecules

14. SIMPLE DIFFUSION

15. Diffusion through protein channels • SELECTIVE PERMEABILITY • GATING MECHANISM IN PROTEIN CHANNELS Voltage gated channels Ligand gated channels

19. Facilitated Diffusion Diffusion of specific particles through transport proteins found in the membrane • Transport Proteins are specific – they “select” only certain molecules to cross the membrane • Transports larger molecules

21. Facilitated Diffusion Glucose molecules Cellular Transport From a- High High Concentration Cell Membrane Protein channel Low Concentration Low Transport Protein Through a 

22. Facilitated Diffusion through a membrane Cell membrane Protein channel Outside cell Inside cell

23. Facilitated Diffusion through a membrane Cell membrane diffusion Protein channel Outside cell Inside cell

24. Facilitated Diffusion through a membrane Cell membrane diffusion Protein channel Outside cell Inside cell EQUILIBRIUM

25. A B Diffusion (Protein Channel) Diffusion (Lipid Bilayer) Facilitated diffusionCarrier Protein

27. Osmosis ‘The diffusion of water from an area of high concentration of water molecules to an area of low concentration of water across a partially permeable membrane.’

28. Osmosis CONCENTRATED SOLUTION DILUTE SOLUTION Cell membrane partially permeable. Sugar molecule VERY Low conc. of water molecules. VERY High conc. of water molecules. Outside cell Inside cell

29. Osmosis Cell membrane partially permeable. Low conc. of water molecules. OSMOSIS High conc. of water molecules. Outside cell Inside cell

30. SUMMARY

31. REFERENCES • Comprehensive Textbook of Medical physiology (Vol 1 first edition)- G K Pal 2. Text book of medical physiology (Vol 2 6 th edition)- A K Jain.