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Biology Lecture Slide Week 2


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Biology Lecture Slide Week 2

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Biology Lecture Slide Week 2

  2. 2. IN THIS TOPIC Structure and functions : Cell wall Cell membrane Organelles Movement of molecules/substancesin and out of the cell
  3. 3. CELL WALL
  4. 4.  Outside the cell membrane In plant cell, prokaryotes, some protista andfungi only. Components : middle lamella primary wall secondary wall Plasmodesmata
  5. 5.  Land plants : Cellulose Lignin Suberin Waxy Waterproof (some tissue) Functions : Cell shape Support and mechanical strength Prevent haemolysis „skin‟ Carbohydrate store
  7. 7.  Both in animal and plant cell Selective permeable Composed of : Proteins Glycoprotein Glycolipids Phospholipid Cholesterol and lipoprotein (a few)
  8. 8.  Fluid mosaic model Lipid bilayer Phospholipid Hydrophilic head (polar) Hydrophobic tail (non-polar) Embedded protein Embedded between layer Integral protein Peripheral protein (not embedded) Free movement within layer As carrier and channel protein Cholesterol Make phospholipid stay in position ‘Fluid’ protein and lipid molecules able to shift and move laterally ‘Mosaic’ the protein molecules form mosaic-like patterns when viewed fromthe top.
  9. 9.  Functions of cell membrane Barrier Maintain internal environment of cell Communication between cell Markers to foreign materials Transportation(Text book page 29)
  10. 10. ORGANELLES
  11. 11. 1. Nucleus2. Endoplasmic reticulum3. Golgi apparatus4. Mitochondria5. Lysosomes6. Ribosomes7. Chloroplasts8. Centrioles9. Vesicles
  12. 12. Nucleus
  13. 13. Nucleus ‘The Control Centre’ Available in all eukaryotes excepts ; Sieve tube of phloem R_ _ _ _ oo _ _ _ l l
  14. 14. Components of nucleusnuclear envelopenucleoplasmnucleoluschromatin
  15. 15. Nuclear envelope Two outer membranes (lipid bilayers) Innermost surface has DNA attachment sitesNuclear pore bilayer facing cytoplasm Nuclear envelopebilayer facingnucleoplasm
  16. 16. Nucleolus dark spot in the middle of the nucleus produce ribosomesFunctions : Store genetics material and information Site of cell division Produce RNA & DNA
  17. 17. Endoplasmic reticulum
  18. 18.  In animal cells, continuous with nuclearmembrane Extends throughout cytoplasm Two regions - rough and smoothRough ER Smooth ER
  19. 19.  FunctionsROUGH ER SMOOTH ERProminent in cells that manufactureprotein for export ; digestiveenzymes, hormones, structuralprotein or antibodiesNecessary for steroid synthesis,metabolism and detoxification ofsubstances in liver, phospholipidsynthesis and excitation-contraction coupling in skeletalmuscleWith ribosome Without ribosome
  20. 20. Golgi body
  21. 21.  Puts finishing touches on proteins andlipids that arrive from ER Packages finished material for shipmentto final destinations Material arrives and leaves in vesicles
  22. 22. Mitochondria
  23. 23. ATP-producingpowerhouses(aerobic respiration)Membranes formtwo distinctcompartmentsATP-makingmachineryembedded in innermitochondrialmembrane
  24. 24. outercompartmentinnercompartmentouter membrane inner membranerepeated foldingsof inner membrane(cristae)
  25. 25. Lysosomes
  26. 26.  a vesicle with enzymes digest biological macromolecules ER to Golgi body Autophagy Autolysis
  27. 27. Ribosomes
  28. 28.  Function as the site of mRNA translationduring protein synthesis Free-wheeling in cytoplasm / attached to ER TWO subunits ; small and large
  29. 29. Chloroplasts
  30. 30.  Site of photosynthesis
  31. 31. Centrioles
  32. 32.  Type of cytoskeleton (network of fiber) In mitosis; source of mitotic spindle Functions ; Organise the formation of spindle fiber Organise the formation of cilia and flagella (9+2 /9+3)
  33. 33. vesicles
  34. 34.  a sac In cytoplasm Types ; Lysosome Peroxisome Shuttle vesicles Secretory vesicles Endocytosis vesicles Storage vesicles
  35. 35. ♫ ♪ Take 5 ♫ ♪
  37. 37.  The movement of molecules are based onconcentration gradient Concentration gradient ; Means the number of molecules or ions in oneregion is different than the number in anotherregion In the absence of other forces, a substancemoves from a region where it is moreconcentrated to one where it‟s lessconcentrated - “down” gradient
  38. 38. Passive transportActive transportEndocytosisExocytosis
  39. 39. PASSIVE TRANSPORT Does not require ATP High to low of concentration gradient Types ; Diffusion Osmosis Facilitated diffusion
  40. 40. Diffusion movement of molecules or ions down aconcentration gradient the molecules move using a naturalkinetic energy
  41. 41. what determines the rate of diffusion?
  42. 42. Steepness of concentration gradient◦ Steeper gradient, faster diffusionMolecular size◦ Smaller molecules, faster diffusionTemperature◦ Higher temperature, faster diffusionSurface area◦ Higher surface area, faster diffusion
  43. 43. Molecules that diffuse through cell membranesOxygen – Non-polar sodiffuses very quickly.Carbon dioxide – Polarbut very small sodiffuses quickly.Water – Polar but alsovery small so diffusesquickly.
  44. 44. Simple Diffusionsmall, nonpolar molecules(ex. O2, CO2)Polar molecules(ex. Glucose, water)ions(ex. H+, Na+, K+)LIPID-SOLUBLE WATER-SOLUBLELIPID-SOLUBLE
  45. 45. Facilitated diffusion movement of molecules or ions down a concentration gradient with the help of transport protein Types of transport protein ; Carrier protein Channel protein
  46. 46. glucose transportersolute (glucose)low[ conc‟n] ofglucose outsidecell > insideGlucosebindsProtein changeshapeGlucose is exposed to fluid on theother side of the membrane,detaches, leaves channel
  47. 47. Osmosis Water movement across a partially permeable membrane from an area of high water potential (lowsolute concentration) to an area of lowwater potential (high soluteconcentration)
  48. 48. HypotonicSolutionmembrane permeable towater but not to solutesHypertonicSolution
  49. 49. Tonicity 2% sucrosesolutiondistilled water10%sucrosesolution2%sucrosesolutionHypotonicConditionsHypertonicConditionsIsotonicConditions
  50. 50. Isotonic solution Hypotonic solution Hypertonic solutionH2O H2O(1) Normal (2) LysedH2OH2O H2O H2OAnimalcellPlantcell(4) Flaccid (5) Turgid (6) Shriveled(plasmolyzed)(3) ShriveledPlasmamembraneH2OH2O
  51. 51. ACTIVE TRANSPORT Transport of molecule Low to high of concentration gradient require ATP Involves carrier protein
  52. 52. ATPADPPihigher calciumconcentrationlower calcium concentrationCalciumentertunnelCalciumpumpATPtransfer aphosphategroupShapechange –CareleaseShapereturns o itsrestingposition
  53. 53. ENDOCYTOSIS Transport of macromolecules Involves formation of vesicle Into the cell Two types; Phagocytosis Pinocytosis
  54. 54. phagocyticvesicleediblebacteriumamoebaPhagocytosis
  55. 55.  Phagocytosis; “cellular eating”. In phagocytosis, the cell engulfs a particle byextending pseudopodia around it andpackaging it in a large vacuole. The contents of the vacuole are digestedwhen the vacuole fuses with a lysosome.
  56. 56.  In pinocytosis; “cellular drinking” a cell creates a vesicle around a droplet ofextracellular fluid.
  57. 57. EXOCYTOSIS Transport of molecules Out of a cell Enclosed in vesicle Move to cell surface membrane Fuse release
  58. 58. Both diffusion and facilitated diffusion are forms of passive transport of moleculesdown their concentration gradient, while active transport requires an investment ofenergy to move molecules against their concentration gradient.
  59. 59. Sekian&terima kasih