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Chemical Evolution

Chemical Evolution. Carbohydrates and Lipids. Biochemistry. Systematic study of the molecular nature of life processes: the chemicals that make up of living systems (biochemicals), their organization into cells, and their chemical interactions Biochemicals have no life in themselves

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Chemical Evolution

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  1. Chemical Evolution Carbohydrates and Lipids

  2. Biochemistry • Systematic study of the molecular nature of life processes: the chemicals that make up of living systems (biochemicals), their organization into cells, and their chemical interactions • Biochemicals have no life in themselves • Chemical interactions which sustain life occur only when biochemicals become organized into cells in tissues

  3. Biochemicals • The major biochemicals are carbohydrates, lipids and proteins which provide energy and materials; and nucleic acids, which provide hereditary information needed to sustain life • According to Oparin, each was first produced abiotically by chemical evol-ution and then assembled as first cell

  4. Carbohydrates • Carbohydrates - substances having alcohol (-OH) and either aldehyde (CHO) or ketone (C=O) functional groups • Function: provide energy and materials • Structures: Chain and ring forms coexist with the ring form usually predominating in aqueous solutions

  5. (4 C) Abiotic Synthesis of Carbohydrates (sugars) (3 C) (5 C) (6 C) Mason, Chemical Evolution,Oxford, UK, 1991, 241

  6. Carbohydrates - polyhydroxy aldehydes or ketones Hill/Kolb, "Chemistry for Changing Times", 7th,Prentice Hall, NJ, 19995,456

  7. Ring Structure for Glucose Brady/Holum, "Fundamentals of Chemistry", Wiley, NY, 1988, 1029

  8. Monosaccharides - One Ring Joesten, World of Chemistry: Essentials, Saunders FL, 1993, 206

  9. Monosaccharides - one ring Disaccharide - two rings Disaccharides Joesten, World of Chemistry: Essentials, Saunders FL, 1993, 206

  10. Polysaccharide - Many Rings Glucose is stored in the human body as glycogen which is a polysaccharide having a structure similar to that for starch Hill/Kolb, "Chemistry for Changing Times", 7th,Prentice Hall, NJ, 19995,457

  11. Structure/Property Generalizations • Chemical, physical, and biological properties of biochemicals are determined by their structures • Structurally, biochemicals involve large molecules frequently composed of repeating components (polymers)

  12. Energy-providing Function of Carbohydrates • Glucose is produced in plants by solar energy and chlorophyll catalyst: 6 CO2 + 6H2O => C6H12O6 + 6 O2; DH > 0 • Glucose is water soluble (H-bonding) and is transported to cells where it serves as the source of energy by means of the reaction: • C6H12O6 + 6O2 => 6CO2 + 6H2O;DH < 0

  13. Flow of Energy and Matter Between Plants and Animals Reduction of Carbon Oxidation of Carbon Joesten/Wood, World of Chemistry, 2nd, Saunders, NY, 1996, 491

  14. Lipids • Lipids are the components of cells that are insoluble in water but soluble in non-polar solvents • Include fats, oils, fatty acids, steroids, and some vitamins • Only fats, oils, and fatty acids will be considered in this course

  15. Fatty Acids • Fatty acids are organic acids RCOOH having 7-21 carbon atoms in R group • Fatty acids are classified according to the number of double bonds in the R-group (saturated, if no double bonds; mono-unsaturated, if one double bond; and poly-unsaturated if more than one double bond)

  16. (All C to C single bonds) (One C to C double bond) (More than one C to C double bond) Tro,394

  17. Geometric Isomers • Geometric isomers have the same atoms and the same bonds, but different spatial orientations around a double bond • Differentiated by drawing an imaginary plane perpendicular to the plane containing the C=C (shown as red dotted lines on next slide)

  18. Examples of Geometric Isomers Two like groups located on adjacent C atoms- both above or both below the  red plane: cis-isomer Two like groups located on adjacent C atoms- one above and one below the  red plane: trans-isomer http://www.wpbschoolhouse.btinternet.co.uk/page06/AlkeneStructure.htm

  19. Horton, Biochemistry, 3rd, Prentice Hall,NJ,2002, 167

  20. Fats and Oils • Fats are tri-esters of saturated fatty acids and glycerol - solids at room temperature • Oils are tri-esters of unsaturated fatty acids - liquids at room temperature - kinks at double bonds decrease effectiveness of London Forces between chains

  21. Abiotic Synthesis of Fats and Oils from Fatty Acids Joesten, World of Chemistry: Essentials, Saunders FL, 1993, 210

  22. Membrane Function of Lipids • One function of lipids is to serve as a membrane which separates compon-ents of an animal cell • A fat or oil is converted to a glycero-phospholipid by replacing one non-polar fatty acid unit with a polar unit - combination of a phosphate unit and an amino alcohol unit

  23. Lipids of Cell Membranes Brady/Holum, Chemistry, 3rd, Wiley,NY, 2000, 1060.

  24. Hydrophilic: water-loving Hydrophobic: water-avoiding Glycerophospholipid Representation Brady/Holum, Chemistry, 3rd, Wiley,NY, 2000, 1060.

  25. The Lipid Bilayer of Animal Cell Membranes Structural integrity of an animal cell depends entirely on the sum of many weak forces: London dispersion, dipole, and hydrogen bonding Brady/Holum, Chemistry, 3rd, Wiley,NY, 2000, 1061.

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