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biological-molecules.pptx biological molecules
- 1. Biological Molecules Objectives: Describe thestructure of the molecules that make up living organisms The chemicals found in living organisms • What elements are you made of? • Which 3 elements are most common in your body? • You should know the answer to this!
- 4. Carbon Based Life •Organic molecules contain carbon • Carbon can bond with itself • So it can make chains of varying lengths to form a backbone to which other atoms can bind • This produces a large variety of shaped and sized molecules.
- 6. How do theseelements form compounds? (eg sugar)
- 7. Forming Molecules • Covalentbond: shared electrons, forms molecules, very strong • Ionic bond: opposite charges attract between ions, weaker than covalent • Hydrogen Bonds: hydrostatic forces formed between uneven charges in polar molecules. Weak individually, but may collectively alter the properties of molecules.
- 8. Monomers Polymer Polymerisation Monomer Polymer Aminoacid Polypeptide / Protein Nucleotide Poly-nucleotide (DNA) Monosaccharide (sugar) Polysaccharide (eg starch)
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- 11. Condensation Hydrolysis When monomers bindtogether a water molecule is formed When polymers break down water is added to break the bonds
- 13. Metabolism All the chemicalprocesses in the body (eg breaking down and formation of molecules)
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- 15. Mole • Formula massin grams • 1 mole of carbon = 12g • 1 mole of oxygen = 16g • 1 mole of water = 18g • It is the mass of 6 x 1023 atoms (Avagadro’s number)
- 16. Molar solution • 1mole of a chemical in 1 litre of water 1. How many grams of NaCl would you dissolve in a litre of water to make a 1M solution? 2. How many grams of HCl would be in 2 litres of 1M solution? 3. How much H2SO4 would be in 1 litre of 0.5 M solution? 4. A) If you had a 1M solution of NaOH and you wanted a 0.5M solution what would you do? 4. B) What exact volumes would you use if you wanted to make 100 cm3 of this NaCl
- 18. Carbohydrates Objectives: • Compare monosaccharidesand disaccharides • Describe how to test for reducing and non- reducing sugars Sugars Starter: similarities and differences
- 19. Carbohydrates carbon hydrogen oxygen Monomer= sugar “saccharide” monosaccharide disaccharide polysaccharide sugars
- 20. Monosaccharides • Sweet • Soluble •(CH2O)n • Glucose, galactose, fructose
- 21. Isomers of Glucose •Same formula (C6H12O6) • Different structure
- 22. Disaccharides • 2 monosaccharidesbonded together • Joined by condensation reaction • The bond that joins them is a glycosidic bond Glucose Glucose Glucose Glucose H2O Maltose Glycosidic bond
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- 26. Testing for reducingsugars Use Benedict’s reagent
- 27. Testing for non-reducingsugars • Hydrolyse with acid • Neutralise • Use Bendict’s reagent
- 30. Polysaccharides • Describe howstarch, cellulose and glycogen form • Describe the test for starch Objectives Starter quiz: 1. What type of reaction bonds monosaccharides together? 2. What disaccharide is formed from glucose and fructose? 3. Maltose is a disaccharide made up of two glucose (C6H12O6) monomers. What is the chemical formula of maltose? 4. A student tested a biscuit by adding Benedict’s reagent and heating for 2 minutes. The test was negative. What can he conclude about the biscuit? What further test should he do to improve his conclusion?
- 31. Starter quiz: 1. Whattype of reaction bonds monosaccharides together? 2. What disaccharide is formed from glucose and fructose? 3. Maltose is a disaccharide made up of two glucose (C6H12O6) monomers. What is the chemical formula of maltose? 4. A student tested a biscuit by adding Benedict’s reagent and heating for 2 minutes. The test was negative. What can he conclude about the biscuit? 5. What further test should he do to improve his conclusion? condensation Sucrose C12H22O11 Does not contain reducing sugars Test for non-reducing sugar: Heat with HCl, neutralise, add Benedict’s
- 32. Polysaccharides • Many monosaccharidesjoined together • Glycosidic bonds join all the monosaccharides • All formed by condensation reactions • Large molecules • Insoluble (good for storage) • Starch, cellulose, glycogen
- 33. Polysaccharide Monomer StructureProperty Where found Starch Glycogen Cellulose
- 34. (α glucose) (α glucose) (βglucose)
- 36. Polysaccharide madeof chains of α glucose
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- 38. Polysaccharide madeof chains of α glucose The unbranched chain is wound into a tight coil – giving it a compact shape
- 39. 1. Found inplant cells as small grains: Storage molecule (stores glucose for respiration) Found mainly in seeds and storage organs (eg potato tubers) 2. Not found in animal cells – but is the main source of energy in our diet Function:
- 40. Why is starchsuch a good storage molecule? 1. It is insoluble so it will: • not affect osmosis (eg will not draw water into a cell when starch levels are high) • not diffuse out of a cell 2. It is compact so a lot can be stored in a small place 3. It is hydrolysed to form α glucose – a molecule that is easily transported and readily used in respiration
- 41. Similar structureto starch (α glucose) Shorter than starch More branched than starch
- 42. Function: Carbohydrate storagein animals Stored as small granules in animal cells Mainly found in muscles and the liver Found only in animal cells – never in plant cells
- 43. Why is glycogena good storage molecule? All the same reasons as starch: 1. Insoluble 2. Compact 3. Easily hydrolysed Plus the shorter chains make it even more readily hydrolysed
- 45. Polysaccharide chainmade of β glucose
- 46. Alpha glucose Betaglucose H H H H H OH OH OH CH2OH O OH H H H H H OH OH OH CH2OH O OH
- 47. Alpha glucose Betaglucose H H H H H OH OH OH CH2OH O OH H H H H H OH OH OH CH2OH O OH
- 49. Polysaccharide chainmade of β glucose The CH2OH groups alternate above and below the chain
- 50. Uncoiled, unbranched chainsare formed – running parallel to each other Weak hydrogen bonds form cross-links between parallel chains The large number of H bonds make this a very strong material
- 51. Microfibrils Cellulose moleculesare grouped together into microfibrils
- 52. Microfibrils Cellulose moleculesare grouped together into microfibrils These are arranged in parallel groups: “fibres”
- 53. Function Major componentof plant cell wall Adds rigidity Prevents bursting by exerting inwards pressure on cell This allows cells to become turgid Providing support and structure to produce maximum surface area for photosynthesis to take place
- 54. Polysaccharide Monomer StructureProperty Where found Starch α glucose • Coiled chain • Branched or unbranched. Branched form has many ends – so easy to release glucose • Compact: stored in small space • Insoluble – does not affect water potential, does not diffuse • Hydrolysed into glucose: respiration Grains in plant cells, seeds, storage organs. Human diet! Glycogen α glucose • Coiled chain • Similar, but shorter than starch • More branches – easier to release glucose (animals need more energy than plants as they are more active!) • Insoluble – does not affect water potential, does not diffuse • Hydrolysed into glucose: respiration Storage in animals, bacteria. Cellulose β glucose • Straight, unbranched chains, running parallel to each other • Many H bonds between chains: strong • Microfibrils run in parallel groups to form fibres • Rigid – stops cells bursting and allows plant cells to become turgid = maximum are for photosynthesis Plant cell walls
- 55. Testing for Starch •Add iodine (brown / orange colour) • Blue / black = positive result, starch present • No change = negative result, no starch present
- 56. Sucrose Maltose GlycogenCellulose Made only from glucose molecules joined together Branched molecule Soluble in water 3 Marks (AQA, 2007)
- 57. Sucrose Maltose GlycogenCellulose Made only from glucose molecules joined together Branched molecule Soluble in water 3 Marks (AQA, 2007)
- 58. Sucrose Maltose GlycogenCellulose Made only from glucose molecules joined together x Branched molecule x x x Soluble in water x x 3 Marks (AQA, 2007)
- 60. Lipids Objective • Link thestructure of lipids to their function • Describe how to test for lipids What are lipids like?
- 61. Carbon, hydrogen and oxygen(lower ratio of oxygen than in carbs) Insoluble in water Most common lipids: triglycerides, phospholipids and waxes Fats are solid (at R.T.) Oils are liquid Not polymers like starch and protein Soluble in alcohol and acetone
- 63. • Plasma membranes (phospholipidsand cholesterol)
- 64. • Plasma membranes •energy •35% of our energy (11% saturated)
- 65. • Plasma membranes •energy • protection
- 66. • Plasma membranes •energy • protection • hormones
- 67. • Plasma membranes •energy • protection • hormones • Insulation
- 68. • Plasma membranes •energy • protection • hormones • Insulation • Waterproofing
- 69. Triglycerides Glycerol Fatty acid Fatty acid Fattyacid Triglycerides (main type of fat we eat)
- 70. Triglycerides Glycerol Fatty acid Fatty acid Fattyacid There are many different types of fatty acid, but all have COOH (carboxyl group)
- 71. Triglycerides (main typeof fat we eat) Made of glycerol and 3 fatty acids
- 72. Triglycerides (main typeof fat we eat) Made of glycerol and 3 fatty acids CH2OH CH2OH CH2OH
- 73. Triglycerides (main typeof fat we eat) Fatty acid Fatty acid Fatty acid CH2OH CH2OH CH2OH HOOC HOOC HOOC
- 74. Triglycerides (main typeof fat we eat) Made of glycerol and 3 fatty acids CH2OH CH2OH CH2OH Fatty acid Fatty acid Fatty acid HOOC HOOC HOOC Draw the a diagram to represent the reaction that occurs to create a triglyceride
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- 77. Triglycerides Fatty acid Fatty acid Fattyacid CH2OH CH2OH CH2OH HOOC HOOC HOOC
- 78. Triglycerides Fatty acid Fatty acid Fattyacid CH2OH CH2OH CH2OH HOOC HOOC HOOC
- 79. Triglycerides Fatty acid Fatty acid Fattyacid CH2O CH2O CH2O OC OC OC
- 80. Triglycerides Fatty acid Fatty acid Fattyacid CH2O CH2O CH2O OC OC OC
- 81. Triglycerides Fatty acid Fatty acid Fattyacid CH2O CH2O CH2O OC OC OC
- 82. Triglycerides Fatty acid Fatty acid Fattyacid CH2O CH2O CH2O OC OC OC Triglyceride Fatty acids bind to glycerol with ester bonds
- 83. + 3H2O Triglyceride Fatty acidsbind to glycerol with ester bonds
- 85. Fatty acids canbe saturated or unsaturated
- 87. No double bonds– so more H per C Double bonds – so less H per C 1 double bond More than 1 double bond The more unsaturated the fat is the more liquid it is Animal fats are high in …………. Plant fats are high in …………
- 88. Relating Structure andFunction • High ratio of energy • Low mass:energy ratio • Insoluble • Release water when broken down Explain how these properties help fat perform its function
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- 90. Phospholipids Like the triglyceride– but 1 fatty acid is replaced with a phosphate molecule.
- 91. Phospholipids Like the triglyceride– but 1 fatty acid is replaced with a phosphate molecule. Fatty acid Fatty acid CH2O CH2O CH2 OC OC Phosphate
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- 95. Phospholipids Simplified diagram: Hydrophilic Hydrophobic “Water loving” “Waterhating” Phospholipids are polar
- 96. If you mixedphospholipids with water what would happen?
- 97. If you mixedphospholipids with water what would happen?
- 98. If you mixedphospholipids with water what would happen? Monolayer
- 99. If you mixedphospholipids with water what would happen?
- 100. If you mixedphospholipids with water what would happen? Bilayer
- 101. Test for Lipids 1.Grind or finely chop food sample 2. Add about 1cmdepth to a test tube (for olive oil just add 2 drops) 3. Add 3cm3 ethanol 4. Put bung on test tube 5. Shake at least 10 times to dissolve the lipids in the ethanol 6. Allow to settle 7. Add 3 cm depth of distilled water Result: • white emulsion floating near top of water = lipids present • no white emulsion = no lipids (or level of lipids belwo sensitivity of the test)