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Outer protection             Cell control center             Energy center             Cell processing             St...
Organelle               Organs are specialized                structures in the body that                perform specific...
Cell ProcessesAll cells have to perform the same basicactivities to stay alive:   Use energy   Store materials   Absorb...
Cell Fractionation   A method of separating cell parts to study    their function   Homogenization: disruption of cell  ...
http://richmondschoolbiology.files.wordpress.com/2008/09/cell-fractionation-diagram.jpg?w=652&h=450
Cell Fractionation                     http://www.freewebs.com/ltaing/chpt7.3Cellfractionation.gif
Steps to Cell Fractionation1.       Homogenize2.       Centrifuge         Pellet: larger, more dense components         ...
Topics   Membranes & contents     Plasma membrane, cell wall, cytoplasm   Nucleus & contents     Nucleus, nuclear enve...
Cell Membrane               All cells are surrounded                by a flexible membrane               Also known as t...
Plasma Membrane Structure Cell membrane made of  phospholipid Phospholipids also form  the membrane around  organelles
Phospholipid Bilayer   Bilayer = 2 layers   Each layer is called a leaflet and composed of    phospholipids
Phospholipid Bilayer   Phospholipid arranged so that    hydrophobic tails do not face    water   Water is on the intrace...
Fluid Mosaic Model   Model developed by Singer and Nicolson    (1972) to understand membrane structure   Fluid implies m...
Membrane FluidityMembrane fluidity is affected by: Saturation of fatty acid     Double bonds bends fatty acid chains    ...
Properties of Cholesterol   Large molecular size     Can interrupt intermolecular forces of attraction   Nonpolar     ...
Properties of Cholesterol   Explain which property of cholesterol plays a    more significant role at:     Low temperatu...
Mosaic: Membrane Composition   Membrane Proteins     Integral     Peripheral   Carbohydrates
Integral Membrane Proteins   Embedded in the membrane and spans the    entire width of the bilayer   Function: transport...
Peripheral Membrane Proteins   Bound non-covalently to either surface of the    membrane   Function     Extracellular s...
Extracellular Peripheral Protein   Receptor and recognition proteins   Located on outer leaflet and surface   Example: ...
Intracellular Peripheral Protein   Cytoskeletal protein   Located on inner membrane surface   Attached to cytoskeleton ...
Carbohydrates   Glycoprotein = carbohydrate + protein   Glycolipid = carbohydate + lipid (phospholipid)   Extracellular...
Asymmetry   Each leaflet has a different composition   Leaflet facing the intracellular side has different    components...
Phospholipid Bilayer
Phospholipid Bilayer
Cell Wall               Found outside of the                cell membrane in                plant and prokaroytes        ...
Cell Wall Structure   Basic composition like steel-reinforced concrete:    microfibrils made of cellulose embedded in a  ...
Cell Wall Structure   Primary cell wall: in young plants, thin and    flexible   Middle lamella: thin layer of pectin (s...
Cytoplasm             Also known as the cytosol             Mostly made of water             Can range from a liquid to...
Nucleus             Control centre of the              cell             Contains genetic              information (e.g. ...
Nucleolus               Darker area in the                nucleus               Synthesis of rRNA                (riboso...
Ribosome Structure                     RNA protein complex                      2/3 RNA (double                       str...
Ribosome Structure                                        2 subunits:                                             large ...
Ribosomes               Made in nucleolus               Can be bound to the                rough endoplasmic            ...
Endomembrane SystemOrganelles of theendomembranesystem arerelated through: direct physical  contact transfer of  membran...
   Nuclear envelope   Rough and Smooth ER    Endomembrane System    Golgi Body   Lysosome   Vacuole   Vesicles      ...
Endoplasmic Reticulum Structure                   Cisternae: network                    of flattened,                    ...
Endoplasmic Reticulum Types   Two types of ER are distinct but connected:    rough and smooth
Rough Endoplasmic Reticulum   Contains ribosomes bound to its membrane surface   Produces integral and secretory protein...
Smooth Endoplasmic Reticulum   No ribosomes on its membrane surface   Site for lipid synthesis
Golgi Body Structure                Also consists of cisternae:                 flattened, stacked,                 inter...
Golgi Body Function Modifies proteins and  lipids Process materials to be  removed from the cell Directs secretion:    ...
Golgi Body                                         Golgi is polar: cis and                                          trans...
Golgi Body   Trans face     “shipping” side     Vesicles bud from      Golgi to various      locations   Targets of ve...
Lysosome   Membrane bound    sac of hydrolytic    enzymes   Enzyme and    lysosomal    membrane made    by RER and    tr...
Lysosome   Enzymes work best    at pH 5   Maintains acidic pH    by pumping H+ into    the lumen   Why would a cell    ...
Lysosome FunctionPhagocytosis lysosome fuse with food  vacuole to digest food  (acts similarly to  stomach in animals) M...
Lysosome Function               Autophagy: lysosome                recycles cell’s own organic                material   ...
Vacuole Structure                 Fluid-filled membrane                  bound sac surrounded                 Similar to...
Vacuole Function                 General:                   Storage of food, water,                    waste            ...
Types of Vacuoles   Food vacuole: formed by phagocytosis, fuses    with a lysosome to digest food and invaders   Contrac...
Endomembrane System   Can you    describe what    is happening    at each    phase?                    http://www.yellowt...
Organelles in Metabolic Function   Mitochondria   Chloroplast   Peroxisome
Mitochondria Structure                    Surrounded by a                     double membrane                    Inner m...
Mitochondria Function               Produces energy through a                process called cellular                respi...
Mitochondria                  Cells that are very active                   (e.g. muscle cells)                   contain ...
Chloroplast Structure                     Surrounded by a                      double membrane                     Conta...
Chloroplast Structure                   Thyakoid: flattened                    discs (some are                    interco...
Chloroplast Function                Site for starch (a type of                 sugar) storage                Site for ph...
Perioxisome Function Contain enzymes that oxidize organic molecules by  transferring hydrogen from substrate to oxygen P...
Peroxisome Structure   Bound by a single    membrane   Spherical with a    distinct crystalline    core that is a dense ...
Cytoskeleton                  A network of fibers                   extending                   throughout the           ...
CytoskeletonComponent   Microfilament:    actin   Intermediate    filament   Microtubules:    tubulin                  ...
Cytoskeleton Component            http://www.sciencephoto.com/image/395087/530wm/C0097406-Cytoskeleton_components,_diagram...
Cytoskeleton ComponentType            Microfilament Intermediate                                         Microtubule      ...
Cytoskeleton ComponentType            Microfilament Intermediate                                          Microtubule     ...
Cytoskeleton   Fluorescent    light    micrograph of    fibroblast cells   Nuclei (green)   Cytoskeleton:     actin   ...
Cytoskeleton Cellular FunctionSummary                  Microfilament:                   mechanical support to            ...
Centrosome                A region near the                 nucleus where                 microtubules grow              ...
Centrioles   Exists as pairs in animal cells only   Composed of 9 sets of triplet microtubules    arranged in a ring   ...
HW Question1.   Give 2 reasons why it is better for an animal cell to     have organelles rather than to perform all its  ...
Summary of DifferencesFunction     Animal      Plant  Outerprotection Energy centre StorageCentrioles
Summary by Cellular Processes     Function         Organelle & cell partsOuter protectionCell control centreEnergy centreC...
Organelles
Organelles
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Organelles

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Organelles

  1. 1. Outer protection Cell control center Energy center Cell processing Storage and Waste Cell divisionCell Parts
  2. 2. Organelle  Organs are specialized structures in the body that perform specific life processes  Organelles are specialized structures inside the cell that perform specific cellular processes  Most organelles are surrounded by a membrane
  3. 3. Cell ProcessesAll cells have to perform the same basicactivities to stay alive:  Use energy  Store materials  Absorb materials  Transport substances  Eliminate waste  Reproduce
  4. 4. Cell Fractionation A method of separating cell parts to study their function Homogenization: disruption of cell membrane without damaging organelle Centrifuge: instrument that spins at high speeds to separate contents by density
  5. 5. http://richmondschoolbiology.files.wordpress.com/2008/09/cell-fractionation-diagram.jpg?w=652&h=450
  6. 6. Cell Fractionation http://www.freewebs.com/ltaing/chpt7.3Cellfractionation.gif
  7. 7. Steps to Cell Fractionation1. Homogenize2. Centrifuge  Pellet: larger, more dense components  Supernatant: lighter, suspended in liquid above the pellet3. Decant supernatant4. Repeat centrifugation at higher speeds to separate into smaller components
  8. 8. Topics Membranes & contents  Plasma membrane, cell wall, cytoplasm Nucleus & contents  Nucleus, nuclear envelope, nucleolus, ribosome Endomembrane System  ER, Golgi body, lysosome, vacuole, vesicles Organelles in metabolism  Mitochondria, chloroplast, peroxisome Cytoskeleton  Microfilament, intermediate filament, microtubule
  9. 9. Cell Membrane  All cells are surrounded by a flexible membrane  Also known as the plasma membrane  Controls exchange of material between interior of the cell and the external environment  Protection
  10. 10. Plasma Membrane Structure Cell membrane made of phospholipid Phospholipids also form the membrane around organelles
  11. 11. Phospholipid Bilayer Bilayer = 2 layers Each layer is called a leaflet and composed of phospholipids
  12. 12. Phospholipid Bilayer Phospholipid arranged so that hydrophobic tails do not face water Water is on the intracellular and extracellular side Hydrophobic tails face inwards forming a hydrophobic core Hydrophilic heads face outwards
  13. 13. Fluid Mosaic Model Model developed by Singer and Nicolson (1972) to understand membrane structure Fluid implies movement on membrane Mosaic implies that the membrane consists of many different molecules
  14. 14. Membrane FluidityMembrane fluidity is affected by: Saturation of fatty acid  Double bonds bends fatty acid chains preventing phospholipids from tight packing Hydrophobic restrictions  Lateral movement: across same leaflet  Flip-flop movement is rare Cholesterol and temperature
  15. 15. Properties of Cholesterol Large molecular size  Can interrupt intermolecular forces of attraction Nonpolar  Stabilizes hydrophobic interactions
  16. 16. Properties of Cholesterol Explain which property of cholesterol plays a more significant role at:  Low temperature  High temperature Why is this advantageous for a cell?
  17. 17. Mosaic: Membrane Composition Membrane Proteins  Integral  Peripheral Carbohydrates
  18. 18. Integral Membrane Proteins Embedded in the membrane and spans the entire width of the bilayer Function: transport  Assist in movement of molecules into and out of cell Classification  type of transport: active or passive  direction of transport: Uniport, symport, antiport (more about this in the Membrane Transport lesson)
  19. 19. Peripheral Membrane Proteins Bound non-covalently to either surface of the membrane Function  Extracellular side: communication  Intracellular side: structural support
  20. 20. Extracellular Peripheral Protein Receptor and recognition proteins Located on outer leaflet and surface Example: antigens, glycoproteins
  21. 21. Intracellular Peripheral Protein Cytoskeletal protein Located on inner membrane surface Attached to cytoskeleton of cell Immobilized (anchored) on membrane
  22. 22. Carbohydrates Glycoprotein = carbohydrate + protein Glycolipid = carbohydate + lipid (phospholipid) Extracellular side Function of cell surface carbohydrates:  identifies the cell (like a name) helping other cells recognize it  acts as a signal for communication
  23. 23. Asymmetry Each leaflet has a different composition Leaflet facing the intracellular side has different components compared to the extracellular side Restrictions in the flip-flop motion help to maintain this asymmetry
  24. 24. Phospholipid Bilayer
  25. 25. Phospholipid Bilayer
  26. 26. Cell Wall  Found outside of the cell membrane in plant and prokaroytes  Rigid but porous  Gives shape and support  Provide protection from injury
  27. 27. Cell Wall Structure Basic composition like steel-reinforced concrete: microfibrils made of cellulose embedded in a matrix of other polysaccharides and proteins
  28. 28. Cell Wall Structure Primary cell wall: in young plants, thin and flexible Middle lamella: thin layer of pectin (sticky) Secondary cell wall: in mature plants, between primary cell wall and cell membrane Plasmodesmata: perforations in the cell wall that connect adjacent cells
  29. 29. Cytoplasm  Also known as the cytosol  Mostly made of water  Can range from a liquid to a jelly-like substance  Contains dissolved substances  Organelles are suspended in the cytoplasm (but are anchored by cytoskeleton and not freely floating)
  30. 30. Nucleus  Control centre of the cell  Contains genetic information (e.g. chromosomes)  Contains nucleolus  Surrounded by a nuclear membrane  Nuclear membrane is double layered and has pores
  31. 31. Nucleolus  Darker area in the nucleus  Synthesis of rRNA (ribosomal RNA)  Assembly of rRNA with protein imported from the cytoplasm to form the large and small ribosomal subunits
  32. 32. Ribosome Structure RNA protein complex  2/3 RNA (double stranded coils in turquoise, grey, orange, indigo)  1/3 protein (small coiled alpha helices in violet and navy blue) http://rna.ucsc.edu/rnacenter/images/70s_atrna.jpg
  33. 33. Ribosome Structure  2 subunits:  large (turquoise colour)  small (lime green colour) http://www.ks.uiuc.edu/Gallery/Science/translation_proteins/tn/ribosome_ao_small_st.jpg.html
  34. 34. Ribosomes  Made in nucleolus  Can be bound to the rough endoplasmic reticulum or float freely in cytoplasm  Function to catalyze the reactions of protein synthesis
  35. 35. Endomembrane SystemOrganelles of theendomembranesystem arerelated through: direct physical contact transfer of membrane segments as vesicles http://www.science-art.com/gallery/52/52_10202008105023.jpg
  36. 36.  Nuclear envelope Rough and Smooth ER Endomembrane System Golgi Body Lysosome Vacuole Vesicles http://bioserv.fiu.edu/~walterm/fallspring/cell_components/cell_talk_files/image010.jpg
  37. 37. Endoplasmic Reticulum Structure  Cisternae: network of flattened, interconnected membrane sacs (tubes and pockets)  Continuous with the nuclear envelope
  38. 38. Endoplasmic Reticulum Types Two types of ER are distinct but connected: rough and smooth
  39. 39. Rough Endoplasmic Reticulum Contains ribosomes bound to its membrane surface Produces integral and secretory proteins:  Integral proteins are embedded in the ER membrane and will end up on the plasma membrane  Secretory proteins are housed in the cisternal space of the ER and will be secreted by exocytosis  Both protein types will be delivered to the cell surface via transport vesicles Note: Free ribosomes produce cytosolic proteins
  40. 40. Smooth Endoplasmic Reticulum No ribosomes on its membrane surface Site for lipid synthesis
  41. 41. Golgi Body Structure  Also consists of cisternae: flattened, stacked, interconnected membrane sacs (similar to ER)  Located near ER  Also known as the Golgi apparatus
  42. 42. Golgi Body Function Modifies proteins and lipids Process materials to be removed from the cell Directs secretion:  Make and secrete mucus  Packages products into vesicles for transport  Sorts and targets vesicle to various parts of the cell
  43. 43. Golgi Body  Golgi is polar: cis and trans poles  Cis face  “receiving” side  Located near the ER  Transport vesicles bud from ER and add its membrane and content of the lumen to Golgi http://4.bp.blogspot.com/_rBYpndaJ_ak/S-sxGmLUOuI/AAAAAAAAAGM/oKWwbrO41-U/s1600/Golgi+apparatus.gif
  44. 44. Golgi Body Trans face  “shipping” side  Vesicles bud from Golgi to various locations Targets of vesicles:  Other organelles  Cytoplasm  Plasma membrane surface  Export - outside cell http://4.bp.blogspot.com/_rBYpndaJ_ak/S-sxGmLUOuI/AAAAAAAAAGM/oKWwbrO41-U/s1600/Golgi+apparatus.gif
  45. 45. Lysosome Membrane bound sac of hydrolytic enzymes Enzyme and lysosomal membrane made by RER and transferred to Golgi http://www.daviddarling.info/images/lysosome.gif
  46. 46. Lysosome Enzymes work best at pH 5 Maintains acidic pH by pumping H+ into the lumen Why would a cell want lysosomal enzymes to function at a pH that is different from the cytosol (neutral pH)? http://www.daviddarling.info/images/lysosome.gif
  47. 47. Lysosome FunctionPhagocytosis lysosome fuse with food vacuole to digest food (acts similarly to stomach in animals) Mostly in small organisms (e.g. amoeba) Seen in some human cells: macrophages http://kvhs.nbed.nb.ca/gallant/biology/lysosome.jpg
  48. 48. Lysosome Function  Autophagy: lysosome recycles cell’s own organic material  Important in development of multicellular organisms  Tadpole to frog: destroy cells of tail  Human embryos: destroy webbing between fingers http://kvhs.nbed.nb.ca/gallant/biology/lysosome.jpg
  49. 49. Vacuole Structure  Fluid-filled membrane bound sac surrounded  Similar to vesicles but tend to be larger  Derived from the ER and Golgi  In animal cells: many small vacuoles  In plant cells: one large central vacuole
  50. 50. Vacuole Function  General:  Storage of food, water, waste  Removing unwanted substances from the cell
  51. 51. Types of Vacuoles Food vacuole: formed by phagocytosis, fuses with a lysosome to digest food and invaders Contractile vacuole: in freshwater protists, pump excess water out of the cell Central vacuole: in plants, maintaining internal fluid pressure (turgor) which helps gives plants structure and strength
  52. 52. Endomembrane System Can you describe what is happening at each phase? http://www.yellowtang.org/images/how_endomembrane_sy_c_la_784.jpg
  53. 53. Organelles in Metabolic Function Mitochondria Chloroplast Peroxisome
  54. 54. Mitochondria Structure  Surrounded by a double membrane  Inner membrane is folded to increase the surface area  Reactions occur on the inner membrane surface
  55. 55. Mitochondria Function  Produces energy through a process called cellular respiration  Reaction involves converting energy from food (e.g. sugars) to cellular energy  Process that occurs inside the mitochondria is aerobic (requires oxygen) glucose + O2 CO2 + H2O + energy
  56. 56. Mitochondria  Cells that are very active (e.g. muscle cells) contain many mitochondria  Cells that are fairly inactive (e.g. fat cells) only have a few mitochondria
  57. 57. Chloroplast Structure  Surrounded by a double membrane  Contain chlorophyll, a pigment that gives plants their green colour
  58. 58. Chloroplast Structure  Thyakoid: flattened discs (some are interconnected) containing chlorophyll; where light reactionsX of photosynthesis take place  Granum (grana): Stack(s) of thylakoid  Stroma: Space inside chloroplast
  59. 59. Chloroplast Function  Site for starch (a type of sugar) storage  Site for photosynthesis  Reaction involves trapping light energy to create food in the form of sugars  Starting substances are carbon dioxide and water CO2 + H2O + energy  O2 + glucose
  60. 60. Perioxisome Function Contain enzymes that oxidize organic molecules by transferring hydrogen from substrate to oxygen Process is useful for:  breaking down fatty acids  detoxifying alcohol and other harmful compounds Produces hydrogen peroxide (H2O2) as a byproduct  Hydrogen peroxide is toxic to the cell  Contains another enzyme (catalase) that decomposes hydrogen peroxide to water
  61. 61. Peroxisome Structure Bound by a single membrane Spherical with a distinct crystalline core that is a dense collection of enzymes Often located near mitochondria and chloroplast http://www.daviddarling.info/images/peroxisome.jpg
  62. 62. Cytoskeleton  A network of fibers extending throughout the cytoplasm  Dynamic: can be quickly dismantled and reassembled in a new location
  63. 63. CytoskeletonComponent Microfilament: actin Intermediate filament Microtubules: tubulin http://www.sciencephoto.com/image/395086/530wm/C0097404-Cytoskeleton_components,_artwork-SPL.jpg
  64. 64. Cytoskeleton Component http://www.sciencephoto.com/image/395087/530wm/C0097406-Cytoskeleton_components,_diagram-SPL.jpg
  65. 65. Cytoskeleton ComponentType Microfilament Intermediate Microtubule FilamentStructureDiameterIntracellularFunctionOtherFunction http://www.sciencephoto.com/image/395087/530wm/C0097406-Cytoskeleton_components,_diagram-SPL.jpg
  66. 66. Cytoskeleton ComponentType Microfilament Intermediate Microtubule FilamentStructure 2 intertwined Fibrous Hollow tube strands of protein of 13 tubulin actin supercoiled columnsDiameter 7 nm 8-12 nm 25 nmIntracellular Changes in Anchorage Organelle &Function cell shape of organelles chromosome (e.g. furrow) movementOther Muscle Cell motilityFunction contraction (e.g. cilia) http://www.sciencephoto.com/image/395087/530wm/C0097406-Cytoskeleton_components,_diagram-SPL.jpg
  67. 67. Cytoskeleton Fluorescent light micrograph of fibroblast cells Nuclei (green) Cytoskeleton:  actin filaments (purple)  microtubules (yellow) http://www.sciencephoto.com/media/316728/enlarge
  68. 68. Cytoskeleton Cellular FunctionSummary  Microfilament: mechanical support to maintain cell shape  Intermediate filament: anchorage for organelles and cytosolic enzymes  Microtubule: path for organelle, vesicles & chromosomes to travel; originate from centrosome
  69. 69. Centrosome  A region near the nucleus where microtubules grow out from  Involved in organizing spindle fibers during cell division  In animal cells, a pair of centrioles exist within this region
  70. 70. Centrioles Exists as pairs in animal cells only Composed of 9 sets of triplet microtubules arranged in a ring Help organize spindle fibers during cell division
  71. 71. HW Question1. Give 2 reasons why it is better for an animal cell to have organelles rather than to perform all its cellular functions in the cytoplasm. Provide a specific example for your reasons. [3 marks]2. If you were given an illustration of a cross-section of a cell membrane, describe two things that would help you identify the side that faces the outside environment. [2 marks]3. Describe the flow of molecules through the endomembrane system. [5 marks]
  72. 72. Summary of DifferencesFunction Animal Plant Outerprotection Energy centre StorageCentrioles
  73. 73. Summary by Cellular Processes Function Organelle & cell partsOuter protectionCell control centreEnergy centreCell processingStorage andwasteCell division

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