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Biomolecules

Biomolecules. Chapter 3. Organic vs Inorganic. Organic molecules: contain carbon. Different Forms of Glucose. Fats. Are constructed from two types of smaller molecules, a single glycerol and usually three fatty acids Vary in the length and number and locations of double bonds they contain.

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Biomolecules

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  1. Biomolecules Chapter 3

  2. Organic vs Inorganic • Organic molecules: contain carbon

  3. Different Forms of Glucose

  4. Fats • Are constructed from two types of smaller molecules, a single glycerol and usually three fatty acids • Vary in the length and number and locations of double bonds they contain

  5. Amino acids • Are organic molecules possessing both carboxyl and amino groups • Differ in their properties due to differing side chains, called R groups

  6. Ribose

  7. Monosaccharides C6H12O6

  8. Disaccharides • Consist of two monosaccharides • Are joined by a glycosidic linkage • Examples: • Sucrose • Maltose • Lactose

  9. Polysaccharides • Are polymers of sugars • Serve many roles in organisms • Examples: • Glycogen • Starch • Cellulose

  10. Glycogen granules Mitochondria 0.5 m Glycogen Figure 5.6 (b) Glycogen: an animal polysaccharide Glycogen • Polysaccharide consisting of glucose monomers • Stores glucose in liver and muscles in animals

  11. Lactose • Disaccharide • Makes up some of the solutes in milk

  12. Glucose • Monosaccharide • Chemical fuel for cell respiration

  13. Fructose • Monosaccharide • Found in many fruits (makes them sweet)

  14. Sucrose • Disaccharide • Transported from leaves to other locations in plants by vascular tissue

  15. Important Polysaccharides: Cellulose • Composed of glucose subunits • Structural component in plant cell walls

  16. Dehydration Synthesis of a Disaccharide

  17. Formation of Disaccharides

  18. Hydrolysis of a Disaccharide

  19. R O H N C C H OH H General structure of an amino acid R group carboxyl group amino group (acidic) (basic)

  20. R1 R2 O O H H N N C C C C H H OH OH H H R1 O R2 H O H N C C N C C H OH H H Formation of a dipeptide: carboxyl group of one amino acid reacts with amino group of second amino acid water molecule formed H2O a dipeptide peptide linkage

  21. R2 R1 O O H H N N C C C C H H OH OH H H R1 O H R2 O H N C C N C C H OH H H Formation of a dipeptide produces a molecule of water, therefore… H2O …this is a condensation reaction 2 amino acids dipeptide + water

  22. R2 R1 O O H H N N C C C C H H OH OH H H R1 O H R2 O H N C C N C C H OH H H Splitting a dipeptide to form two amino acids consumes one molecule of water, therefore… H2O …this is a hydrolysis reaction dipeptide + water  2 amino acids

  23. Glycerol H H H C C C H H OH OH OH Hydroxyl groups Triglycerides are one of the most common types of lipids  Triglycerides consist of one molecule of glycerol bonded to three fatty acid molecules  Each fatty acid is linked to the glycerol molecule by an ester bond

  24. General Formula: O (CH2)n CH3 O C Carboxyl group OH C OH H H H H H H H C C C C C C H H H H H H CH2 CH3 Fatty Acids:

  25. O O C C OH OH H H H H H H H C C C C C C H H H H H H Can be drawn as:

  26. H Hydroxyl group and carboxyl group react O H C OH O C OH Ester bond H C H OH C H OH C O H C H OH H C H OH C H Forming a monoglyceride: + H2O This is a condensation reaction

  27. H O O O H C C C C O O H C O H C Fatty acid H Fatty acid Glycerol Fatty acid Ester bond A triglyceride: Can be drawn as:

  28. H O H C OH O C OH H C H OH C H OH C O H C H OH H C H OH C H To split these ester bonds and separate a fatty acid from glycerol we need to add a molecule of water + H2O This is a hydrolysis reaction

  29. Human Adipose Tissue Plant Oils Uses of Lipids in Living Things 1. Long-term energy stores

  30. 2. Buoyancy for marine animals: lipids are less dense than water so help animals float 3. Insulation: a layer of fat beneath the skin cuts down heat loss

  31. e.g. C17H35COOH + 26 O2 18 CO2 + 18 H2O (a typical fatty acid) 4. Production of water: fatty acids produce a lot of metabolic water when they are oxidised during respiration Camels’ humps are made of fat

  32. (a) Dehydration reaction in the synthesis of maltose. The bonding of two glucose units forms maltose. The glycosidic link joins the number 1 carbon of one glucose to the number 4 carbon of the second glucose. Joining the glucose monomers in a different way would result in a different disaccharide. CH2OH CH2OH CH2OH CH2OH O O O O H H H H H H H H 1–4glycosidiclinkage HOH HOH HOH HOH 4 1 H H H H OH OH O H OH HO HO OH O H H H H OH OH OH OH H2O Glucose Maltose Glucose CH2OH CH2OH CH2OH CH2OH O O O O 1–2glycosidiclinkage H H H H H HOH HOH H 2 1 H OH H HO H HO H Dehydration reaction in the synthesis of sucrose. Sucrose is a disaccharide formed from glucose and fructose.Notice that fructose,though a hexose like glucose, forms a five-sided ring. (b) HO H O O HO CH2OH CH2OH OH H OH H H H OH OH H2O Glucose Sucrose Fructose Figure 5.5

  33. Lipids vs. Carbohydrates • Lipids and carbohydrates are efficient molecules for energy storage • If you eat more than you burn, it’s stored as fat • Lipids store twice as much energy as carbohydrates

  34. PROTEINS1°- Primary Structure • 1° structure is the number and sequence of the amino acids in the polypeptide • Gene sequence determines the amino acids • Consist of between 50 and 1000 amino acids

  35. 2° - Secondary structure • 2º structures are regular repeating patterns within the polypeptide • One type of 2º structure is and alpha helix (helicies)

  36. 2° - Secondary structure • They form by Hydrogen bonds forming between groups in the main chain • Another 2º structure is beta (ß) pleated sheets • Some proteins form both A-helicies and ß-sheets • Some proteins only form 2º structures in a portion of the molecule

  37. 3º - Tertiary Structure • 3° structure is the 3-D conformation of the polypeptide • Stabilized by intramolecular bonds between the a.a. of the polypeptide, especially the R Groups • Sometimes called the sausage model

  38. 4º - Quaternary Structure • 4° structure is the linking together of two or more polypeptides to form a single protein • Some proteins contain a non-polypeptide structure called a prosthetic group • Proteins with prosthetic groups are called conjugated proteins • Hemoglobin has 4 polypeptides w/ 4 prosthetic groups

  39. Fibrous Proteins • Proteins can be divided into two types according to their shape • Fibrous proteins have long narrow shape • Found only in animals • Insoluble in Water • Usually used to construct connective tissue, tendons, bone matrix and muscle fiber

  40. Globular Proteins • Have a rounded shape • They are mostly insoluble in water • Act as enzymes, messengers and transporters

  41. Protein Functions

  42. Polar vs. Non-Polar Amino Acids Polar • Have side chains that are polar that make them reactive (hydrophillic-water loving) • Are reactive with many substances

  43. Non-polar • Have side chains that are not polar (hydrophillic-water fearing) • Not reactive

  44. Proteins have polar regions and non-polar regions • Non-polar regions (hydrophobic) allow proteins to remain embedded in the plasma membrane • Polar regions (hydrophillic) create channels in membranes that allow other hydrophillic substances to diffuse

  45. Polar regions on the outside of a protein allow it to be water soluble • Non-polar regions on the inside give a protein stability • Polar regions also affect the binding of a substrate to an enzyme

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