1 / 47

Movement of substances across the plasma membrane

Movement of substances across the plasma membrane. Metabolism : all the chemical activities taking place in the cell Consists of two processes: Anabolism Catabolism. Anabolism : the building up of molecules E.g. : synthesis of protein and ATPs, which a cell needs Catabolism :

suchi
Download Presentation

Movement of substances across the plasma membrane

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. Movement of substances across the plasma membrane

  2. Metabolism : • all the chemical activities taking place in the cell • Consists of two processes: • Anabolism • Catabolism Tr.Rez@SB2013

  3. Anabolism : • the building up of molecules • E.g. : synthesis of protein and ATPs, which a cell needs • Catabolism : • breaking down of large molecules to smaller simpler molecules. • E.g. : oxidation of glucose in cell respiration Tr.Rez@SB2013

  4. Substances that leave the cell Tr.Rez@SB2013

  5. Substances that enter the cell Tr.Rez@SB2013

  6. The structure of plasma membrane

  7. Phospholipid bilayer consists of: • A polar phosphate molecule head which is hydrophilic • Two non-polar fatty acid tails which are hydrophobic Tr.Rez@SB2013

  8. Tr.Rez@SB2013

  9. Permeability of the plasma membrane

  10. Permeability of the phospholipids bilayer • Plasma membrane : • semi-permeable • Allows only certain substances to pass through but not other Tr.Rez@SB2013

  11. Permeability of the phospholipids bilayer • Phospholipid bilayer is permeable to: • Small non-polar (hydrophobic) molecules that are lipid soluble, such as : fatty acids, glycerol, steroids, vitamin A, D, E and K • Small uncharged molecules, such as: water, oxygen and carbon dioxide Tr.Rez@SB2013

  12. Phospholipidbilayer is not permeable to: • Large polar molecules that are not soluble in lipid, such as glucose amino acids, nucleic acids and polysaccharides • Ions (charged), regardless of size, such as: H+, Na+ Tr.Rez@SB2013

  13. Types of transport across the plasma membrane

  14. Tr.Rez@SB2013

  15. Passive transport

  16. Simple Diffusion • Random movement of ions/molecules from a region of their high concentration to a region of their low concentration down a concentration gradient until an equilibrium is achieved • Molecules that can cross are • Small non-polar (hydrophobic) molecules • Small uncharged molecules Tr.Rez@SB2013

  17. Tr.Rez@SB2013

  18. Tr.Rez@SB2013

  19. Factors affecting the rate of diffusion: • Diffusion gradient • Size of molecules or ions • Temperature • Diffusion medium • Surface area Tr.Rez@SB2013

  20. Tr.Rez@SB2013

  21. Facilitated diffusion

  22. Facilitated diffusion • Movement of specific molecules (or ions) across the plasma membrane • Assisted by pore proteins / carrier proteins Tr.Rez@SB2013

  23. Pore protein (channel protein) • Charged ions • Open up pore / channels across the membrane to allow entry or exit • Specific Tr.Rez@SB2013

  24. Tr.Rez@SB2013

  25. Carrier proteins • Allow larger polar molecules (such as sugar & amino acids) to cross • A particular protein attaches itself to the binding site of a carrier protein • Then, the carrier protein changes shape and delivers the molecule across the plasma membrane Tr.Rez@SB2013

  26. Tr.Rez@SB2013

  27. Tr.Rez@SB2013

  28. Osmosis • movement of water molecules from a region of low solute concentration (high water concentration) to a region of high solute concentration (low water concentration) through semi-permeable membrane Tr.Rez@SB2013

  29. Tr.Rez@SB2013

  30. Examples of osmosis: • Absorption of water by root hairs • Movement of water from one cell to another • Absorption of water in the alimentary canal-stomach, small intestine and colon Tr.Rez@SB2013

  31. Active Transport • Uses carrier proteins and energy to move molecules or ions across the plasma membrane against the concentration gradient Tr.Rez@SB2013

  32. Example of active transport: • Absorption of mineral salts by roots hairs • Absorption of glucose and amino acids by cells in the small intestine Tr.Rez@SB2013

  33. The processes of passive transport and active transport in living organisms

  34. Gaseous exchange in the alveoli and blood capillaries by simple diffusion Tr.Rez@SB2013

  35. Absorption of digested food in the villi Tr.Rez@SB2013

  36. Absorption of water in root hairs of plants by osmosis Tr.Rez@SB2013

  37. 3.2 movement of substances across the plasma membrane in everyday life

  38. Hypotonic, hypertonic and isotonic solution • Isotonic solution : • Solution A and Solution B have the same solute concentration • Hypertonic solution : • Solution A is hypertonic to solution B if solution A has a higher solute concentration • Hypotonic solution: • Solution A is hypotonic to solution B if solution A has lower solute concentration than solution B Tr.Rez@SB2013

  39. Effects of hypotonic, hypertonic and isotonic solutions on plant cell

  40. crenation haemolysis Tr.Rez@SB2013

  41. Plasmolysed (flaccid) turgid Tr.Rez@SB2013

  42. Tr.Rez@SB2013

  43. Phenomenon of wilting in plants

  44. Excessive use of chemical fertilizers release huge amount of ions, such as phosphates, nitrates, calcium, magnesium, and sulphur into soil • Increase solute concentration but decrease water molecules concentration in soil • Water molecules diffuse from the cell sap into soil water by osmosis • Cell plasmolysed, lose turgidity & support = WILT Tr.Rez@SB2013

  45. Preservation of food • Concentrated salt solution has a high concentration of solute (Na+ and Cl- ions) and very low concentration of water molecules • All water molecules inside drawn out by osmosis • Without water, bacteria and water cannot survive Tr.Rez@SB2013

More Related