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MEMBRANE STRUCTURE PowerPoint Presentation
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MEMBRANE STRUCTURE

MEMBRANE STRUCTURE

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MEMBRANE STRUCTURE

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  1. MEMBRANE STRUCTURE LECTURE 4 CHAPTER 10

  2. LIPID CLASSIFICATION • PHOSPHOGLYCERIDES • SPHINGOLIPIDS • STEROIDS

  3. PHOSPHOGLYCERIDES

  4. SPHINGOLIPIDS

  5. STEROIDS

  6. MEMBRANE BILAYER

  7. BILAYER STRUCTURE OF BIOMEMBRANRANES

  8. FORMATION OF PURE PHOSPHOLIPID BILAYERS

  9. PROPERTIES OF MEMBRANES • HYDROPHOBIC CORE IS AN IMPERMEABLE BARRIER • STABILITY – Van der Waals interaction, and hydrophobic interaction stabilize the fatty acyl groups whereas ionic and hydrogen bonds stabilize the polar head groups • PHOSPHOLIPID BILAYERS SPONTANEOUSLY FORM CLOSED SEALED COMPARTMENTS

  10. MEMBRANE BUDDING AND FUSION

  11. CYTOSOLIC AND EXOPLASMIC FACES ARE CONSERVED

  12. LIPID COMPOSITION IN THE EXOPLASMIC AND CYTOSOLIC FACES OF THE MEMBRANES

  13. HOW LIPIDS AFFECT CURVATURE AND THICKNESS OF MEMBRANES

  14. PHOSPHOLIPID BILAYER- lateral and rotational movement

  15. FRAP EXPERIMENTS

  16. FRAP EXPERIMENT (cont’d)

  17. MEMBRANE PROTEINS • INTEGRAL or TRANS – MEMBRANE PROTEINS • LIPID-ANCHORED MEMBRANE PROTEINS • PERIPHERAL MEMBRANE PROTEINS

  18. Integral membrane proteins • Contain membrane spanning α- helices • 20-25 hydrophobic uncharged amino acids (3.75 nm) • Segment is perpendicular to the membrane or is at an oblique angle • Amino peptide bonds in the interior of the α-helix • Hydrophobic side chains interact with fatty acyl groups

  19. GLYCOPHORIN A – single pass integral membrane protein

  20. Multipass Transmembrane Protein

  21. Multiple membrane spanning β strands • Porins • Gram-negative bacteris, outer membrane of mitochondria and chloroplasts • Trimers of identical subunits • Each subunit – 16 beta strands that twist to form a barrel-shaped structure • Barrel - Hydrophilic interior and hydrophobic exterior

  22. Single subunit of outer membrane Porin from E.coli

  23. PERIPHERAL MEMBRANE PROTEINS

  24. HOW IS BLOOD GROUP DETERMINED?

  25. Mechanism of action of Phospholipase A

  26. SOLUBILIZATION OF MEMBRANES

  27. BINDING OF FATTY ACID TO THE FATTY –ACID-BINDING PROTEIN

  28. PHOSPHOLIPID BIOSYNTHESIS

  29. CHOLESTEROL BIOSYNTHESIS

  30. MECHANISM OF CHOLESTEROL AND PHOSPHOLIPID TRANSPORT