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Biochemistry of Cells


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Biochemistry of Cells

  1. 1. Biochemistry of Cells
  2. 2. Uses of Organic MoleculesAmericans consumean average of 140pounds of sugarper person peryearCellulose, found inplant cell walls, isthe most abundantorganic compound onEarth
  3. 3. Uses of Organic MoleculesA typical cell in your body has about 2 meters of DNAA typical cowproduces over200 pounds ofmethane gaseach year
  4. 4. WaterAbout 60-90 percentof an organism iswaterWater is used inmost reactions inthe bodyWater is calledthe universalsolvent
  5. 5. Water PropertiesPolarityCohesiveness AdhesivenessSurfaceTension
  6. 6. Carbon-based MoleculesAlthough a cell ismostly water, therest of the cellconsists mostly ofcarbon-basedmoleculesOrganic chemistryis the study ofcarbon compounds
  7. 7. Carbon is a Versatile AtomIt has four electronsin an outer shell thatholds eightCarbon canshare itselectrons withother atoms toform up to fourcovalent bonds
  8. 8. HydrocarbonsThe simplest carboncompounds … Contain only carbon & hydrogen atoms
  9. 9. Carbon can use its bonds to:: Attach to other carbons Form an endless diversity of carbon skeletons
  10. 10. Large Hydrocarbons:Are the main molecules in the gasoline we burn in our carsThe hydrocarbons of fat moleculesprovide energy for our bodies
  11. 11. Shape of Organic Molecules Each type of organic molecule has a unique three-dimensional shape The shape determines its function in an organism
  12. 12. Functional Groups are:Groups of atoms that give properties to the compounds to which they attach Gained Electrons Lost Electrons
  13. 13. Common Functional Groups
  14. 14. Giant Molecules - PolymersLarge moleculesare called polymersPolymers are builtfrom smallermolecules calledmonomers Biologists call them macromolecules
  15. 15. Examples of PolymersProteinsLipidsCarbohydrates Nucleic Acids
  16. 16. Most Macromolecules are Polymers Polymers are made by stringing together many smaller molecules called monomers Nucleic Acid Monomer
  17. 17. Linking MonomersCells link monomers by a process calledcondensation or dehydration synthesis (removing a molecule of water) Remove H H2O Forms Remove OH This process joins two sugar monomers to make a double sugar
  18. 18. Breaking Down PolymersCells break down macromolecules by a process called hydrolysis (adding a molecule of water) Water added to split a double sugar
  19. 19. Macromolecules in Organisms There are four categories of large molecules in cells: Carbohydrates Lipids Proteins Nucleic Acids
  20. 20. CarbohydratesCarbohydrates include: Small sugar molecules in soft drinksLong starch molecules in pasta and potatoes
  21. 21. Monosaccharides:Called simple sugarsInclude glucose,fructose, & galactoseHave the samechemical, butdifferent structuralformulas C6H12O6
  22. 22. MonosaccharidesGlucose is found insports drinksFructose is foundin fruitsHoney containsboth glucose &fructoseGalactose is called“milk sugar” -OSE ending means SUGAR
  23. 23. IsomersGlucose &fructose areisomersbecausethey’restructures aredifferent, buttheir chemicalformulas arethe same
  24. 24. Rings In aqueous (watery) solutions, monosaccharides form ring structures
  25. 25. Cellular FuelMonosaccharidesare the mainfuel that cellsuse for cellularwork ATP
  26. 26. DisaccharidesA disaccharide is adouble sugarThey’re made byjoining twomonosaccharidesInvolves removinga water molecule(condensation)Bond called a GLYCOSIDIC bond
  27. 27. Disaccharides Common disaccharides include: Sucrose (table sugar) Lactose (Milk Sugar) Maltose (Grain sugar )
  28. 28. DisaccharidesSucrose is composedof glucose + fructoseMaltose iscomposed of 2glucose molecules Lactose is made of galactose + glucose GLUCOSE
  29. 29. PolysaccharidesComplexcarbohydratesComposed of manysugar monomerslinked togetherPolymers ofmonosaccharidechains
  30. 30. Examples of Polysaccharides Glucose Monomer Starch Glycogen Cellulose
  31. 31. StarchStarch is an example of a polysaccharide in plantsPlant cells store starchfor energy Potatoes and grains are major sources of starch in the human diet
  32. 32. GlycogenGlycogen is an example of a polysaccharide in animalsAnimals store excesssugar in the form ofglycogenGlycogen is similar instructure to starch becauseBOTH are made of glucosemonomers
  33. 33. CelluloseCellulose is the most abundant organic compound on EarthIt forms cable-like fibrils in thetough walls that enclose plants It is a major component of wood It is also known as dietary fiber
  34. 34. Cellulose SUGARS
  35. 35. Dietary CelluloseMost animals cannot derive nutrition from fiberThey havebacteria intheir digestivetracts that canbreak downcellulose
  36. 36. Sugars in WaterSimple sugars and double sugars dissolve readily in water WATER MOLECULEThey arehydrophilic,or “water-loving”-OH groups SUGARmake them MOLECULEwater soluble
  37. 37. LipidsLipids are hydrophobic –”water fearing”Do NOT mix with waterIncludesfats,waxes,steroids,& oils FAT MOLECULE
  38. 38. Function of LipidsFats store energy, help to insulate the body, and cushion and protect organs
  39. 39. Types of Fatty AcidsSaturated fatty acids have themaximum number of hydrogens bondedto the carbons (all single bondsbetween carbons)Unsaturated fatty acids have less than the maximum number of hydrogens bonded to the carbons (a double bond between carbons)
  40. 40. Types of Fatty Acids Single Bonds in Carbon chain Double bond in carbon chain
  41. 41. TriglycerideMonomer of lipidsComposed ofGlycerol & 3fatty acid chainsGlycerol formsthe “backbone”of the fat Organic Alcohol (-OL ending)
  42. 42. TriglycerideGlycerol Fatty Acid Chains
  43. 43. Fats in OrganismsMost animal fats have a high proportion of saturated fatty acids & exist as solids at room temperature (butter, margarine, shortening)
  44. 44. Fats in OrganismsMost plant oils tend to be low in saturated fatty acids & exist as liquids at room temperature (oils)
  45. 45. FatsDietary fat consists largely of the molecule triglyceride composed of glycerol and three fatty acid chains Fatty Acid ChainGlycerol Condensation links the fatty acids to Glycerol
  46. 46. Lipids & Cell Membranes• Celllipids called are made of membranes phospholipids• Phospholipids have a head that is polar & attract water (hydrophilic)• Phospholipids also have 2 tails that are nonpolar and do not attract water (hydrophobic)
  47. 47. SteroidsThe carbon skeletonof steroids is bentto form 4 fusedrings CholesterolCholesterol isthe “base Estrogensteroid” from Testosteronewhich your bodyproduces othersteroidsEstrogen & testosterone are also steroids
  48. 48. Synthetic Anabolic SteroidsThey are variantsof testosteroneSome athletes usethem to build uptheir muscles quicklyThey can poseserious health risks
  49. 49. ProteinsProteins are polymers made of monomers called amino acidsAll proteins are made of 20 differentamino acids linked in different ordersProteins are used to build cells, actas hormones & enzymes, and do muchof the work in a cell
  50. 50. Four Types of Proteins StorageStructural Contractile Transport
  51. 51. 20 Amino Acid Monomers
  52. 52. Structure of Amino Acids Amino CarboxylAmino acids have a group groupcentral carbon with4 things boded to R groupit: Amino group –NH2Carboxyl group -COOH Hydrogen -H Side groups Side group -R Serine-hydrophillic Leucine -hydrophobic
  53. 53. Linking Amino Acids CarboxylCells link aminoacids together to Aminomake proteins Side GroupThe process iscalled condensation Dehydrationor dehydration SynthesisPeptide bondsform to hold theamino acidstogether Peptide Bond
  54. 54. Proteins as EnzymesMany proteins act as biological catalysts or enzymesThousands of different enzymes existin the bodyEnzymes control the rate of chemicalreactions by weakening bonds, thuslowering the amount of activationenergy needed for the reaction
  55. 55. Enzymes Enzymes are globular proteins. Their folded conformation creates an area known as the active site. The nature and arrangement of amino acids in the active site make it specific for only one type of substrate.
  56. 56. Enzyme + Substrate = Product
  57. 57. How the Enzyme WorksEnzymesarereusable!!!Active sitechangesSHAPECalledINDUCEDFIT
  58. 58. Primary Protein StructureThe primarystructure isthe specificsequence ofamino acids ina proteinCalledpolypeptide Amino Acid
  59. 59. Protein StructuresSecondary protein structures occur when protein chains coil or foldWhen protein chains called polypeptidesjoin together, the tertiary structureforms because R groups interact witheach otherIn the watery environment of a cell,proteins become globular in theirquaternary structure
  60. 60. Protein Structures or CONFORMATIONS Hydrogen bond Pleated sheet Polypeptide Amino acid (single subunit) (a) Primary structure Hydrogen bond Alpha helix (b) Secondary (c) Tertiary structure structure (d) Quaternary structure
  61. 61. Denaturating Proteins Changes in temperature & pH can denature (unfold) a protein so it no longer worksCooking denaturesprotein in eggs Milk protein separates into curds & whey when it denatures
  62. 62. Changing Amino Acid Sequence Substitution of one amino acid for another in hemoglobin causes sickle-cell disease 2 7. . . 146 1 3 6 4 5 (a) Normal red blood cell Normal hemoglobin 2 7. . . 146 1 3 6 4 5 (b) Sickled red blood cell Sickle-cell hemoglobin
  63. 63. Other Important Proteins•Blood sugar level is controlled bya protein called insulin•Insulin causes the liver to uptakeand store excess sugar asGlycogen•The cell membrane also containsproteins•Receptor proteins help cellsrecognize other cells
  64. 64. INSULIN Cell membrane with proteins & phospholipids
  65. 65. Nucleic AcidsStore hereditary informationContain information for making allthe body’s proteins Two types exist --- DNA & RNA
  66. 66. Nucleic Acids Nitrogenous base (A,G,C, or T)Nucleicacids arepolymers of Phosphate Thymine (T) groupnucleotides Sugar (deoxyribose) Phosphate Base Sugar Nucleotide
  67. 67. Nucleotide – Nucleic acid monomer
  68. 68. Nucleic Acids
  69. 69. BasesEach DNAnucleotide has oneof the followingbases: Thymine (T) Cytosine (C) –Adenine (A) –Guanine (G) –Thymine (T) –Cytosine (C) Adenine (A) Guanine (G)
  70. 70. Nucleotide Monomers BackboneForm long chains Nucleotidecalled DNANucleotides arejoined by sugars& phosphates onthe side Bases DNA strand
  71. 71. DNATwo strands ofDNA jointogether to forma double helix Base pair Double helix
  72. 72. RNA – Ribonucleic Acid Nitrogenous base (A,G,C, or U)Ribose sugarhas an extra–OH orhydroxylgroup Uracil PhosphateIt has the groupbase uracil (U)instead ofthymine (T) Sugar (ribose)
  73. 73. ATP – Cellular Energy•ATP is used by cells for energy•Adenosine triphosphate•Made of a nucleotide with 3phosphate groups
  74. 74. ATP – Cellular Energy• Energy is stored in the chemical bonds of ATP• The last 2 phosphate bonds are HIGH ENERGY• releases energy for cellular work and Breaking the last phosphate bond produces ADP and a free phosphate• ADP (adenosine Diphosphate) can be rejoined to the free phosphate to make more ATP
  75. 75. Summary of Key Concepts
  76. 76. Macromolecules
  77. 77. Macromolecules
  78. 78. End