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Chapter 3 PowerPoint Presentation

Chapter 3

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Chapter 3

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  1. Chapter 3 Molecules of Life

  2. Organic compounds • Always contain carbon • Always have covalent bonds (not ionic) • Usually associated with large numbers of atoms • Commonly associated with living things

  3. carbon • Can covalently bond with as many as 4 other atoms • Can form many shapes

  4. Carbon compounds

  5. Carbon Compounds • Carbohydrates • Lipids • Proteins • Nucleic Acids

  6. Building compounds • Monomer—individual building unit • Polymer—many units covalently bonded

  7. Building compounds • Functional groups—atoms or clusters of atoms covalently bonded to organic compounds that affect the compound’s structure and fuction

  8. Reaction categories • Mediated by enzymes (special proteins) • Fuctional-group transfer • Electron transfer • Rearrangement • Condensation • Cleavage

  9. condensation • Split OH- from one molecule • Split H+ from another molecule • Bonds form at exposed sites • Water is byproduct

  10. hydrolysis • Reverse of condensation • Split molecules • Add OH- and H+ from water

  11. carbohydrates • Monosaccharides • Single sugar unit • Soluble in water • Sweet taste • Hydroxyl group (OH-) • Used to assemble larger carbohydrates

  12. carbohydrates • Oligosaccharide • Short chain of two or more sugar monomers • Disaccharide—2 units, simplest

  13. carbohydrates • Polysaccharide—chain of hundreds or thousands of monomers • “Complex” carbohydrates • Starch—plant energy source • Cellulose—plant cell wall • Glycogen—animal muscle energy • Chitin—structural component of insects

  14. lipids • Greasy or oily compounds • Non-polar, hydrophobic • Energy storage, membrane structure, coatings

  15. Lipids • Fatty acids—long chain of mostly C and H with a carboxyl group (-COOH) at the end • Saturated—single Carbon bonds • Unsaturated—double Carbon bonds

  16. Lipids • Fat—one or more fatty acids attached to glycerol • Twice the energy of carbohydrates • Insulation

  17. Lipids • Phospolipid • 2 Fatty Acids + Phosphate Group + Glycerol • Main structural material of membranes

  18. lipids • Sterols • 4 carbon rings, no fatty acid tails • Cholesterol, testosterone, estrogen

  19. lipids • Waxes • Long-chain fatty acids + alcohols or carbon rings • Coatings for plant parts or animal coverings

  20. Proteins • Most diverse of all biological molecules • Enzymes • Cell movement • Storage & transport • Hormones • Antibodies • Structure

  21. proteins • Amino acid—monomer unit • Three groups covalently bonded to central C

  22. proteins • Polypeptides—polymer of proteins

  23. Proteins • Structure • Primary • Secondary • Tertiary • Quaternary

  24. Proteins • Why is structure important? • Change in shape is VERY important to function

  25. Nucleic acids • Nucleotide—monomer unit • 5-carbon sugar (ribose or deoxyribose) • Nitrogen base • Phosphate group

  26. Nucleic acid • DNA—double-stranded helix, carries hereditary information • RNA—single-stranded helix, translates code to build proteins • ATP—single nucleotide, releases energy for cells to work

  27. DNA & RNA • Large number of hydrogen bonds • Nitrogen bases: Adenine, Cytosine, Guanine, Thymine (Urasil)