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Macromolecules

Macromolecules. The building blocks of life…. Macromolecules. Cells are composed of several types of biological macromolecules. These function as energy-storage molecules, structural components, and in information storage, and are primarily composed of carbon, hydrogen and oxygen.

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Macromolecules

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  1. Macromolecules The building blocks of life…

  2. Macromolecules • Cells are composed of several types of biological macromolecules. • These function as energy-storage molecules, structural components, and in information storage, and are primarily composed of carbon, hydrogen and oxygen.

  3. Carbohydrates • carbon, hydrogen & oxygen in a 1:2:1 ratio • exist as monosaccharides, disaccharides and polysaccharides • among the most abundant molecules on Earth

  4. Monosaccharides • “single sugars” • general formula is (CH2O)n • glucose (top) and ribose (bottom) are monosaccharides

  5. Disaccharides • “double sugars” • formed by dehydration synthesis from two monosaccharides • sucrose, maltose, and lactose are all disaccharides

  6. Synthesis of Maltose - glucose -glucose maltose

  7. Polysaccharides • straight or branched chains of monosaccharides connected by glycosidic linkages • storage (e.g. starch, glycogen) or structural (e.g. cellulose, chitin)

  8. Polysaccharide Structure

  9. Proteins • proteins are chains of amino acids connected by peptide linkages • order of amino acids for a particular protein is determined by the gene which codes for it

  10. Amino Acid Structure • all amino acids have the same basic structure • “R” group is different for each amino acid amino group carboxyl group

  11. Peptide Linkages cysteine glycine peptide linkage

  12. Levels of Protein Structure • Primary • the specific sequence of amino acids • coded by DNA

  13. Secondary • the folding or coiling of the amino acid chain • caused by interactions between “R” groups • -Helix • -Pleated Sheet

  14. Tertiary • the unique three-dimensional shape of the protein • enzymes are globular proteins • collagen is a fibrous protein

  15. Quaternary • interactions between separate polypeptide chains, or “subunits” • hemoglobin is composed of four subunits

  16. Lipids • lipids are a group of hydrophobic molecules • “neutral fats” are uncharged lipids composed of glycerol and fatty acids • fats are solid at room temperature • oils are liquid at room temperature • steroids and phospholipids are amphiphilic

  17. steroids all have the same basic structure of four fused hydrocarbon rings cholesterol is used to synthesize many other steroids in the body Steroid Structure cholesterol

  18. Phospholipid Structure • glycerol backbone has two fatty acids and one charged inorganic phosphate group attached • primary component of cell membranes

  19. Triglycerides • triglycerides are neutral fats • glycerol is the “backbone” molecule • fatty acids attach to glycerol by ester linkages • saturated fatty acids have no double bonds between carbons • unsaturated fatty acids have at least one double bond between carbons

  20. Triglyceride Synthesis 3 fatty acids glycerol ester linkage triglyceride

  21. Nucleic Acids • Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA) • composed of nitrogen-containing “bases” attached to a backbone of alternating pentose sugars and inorganic phosphate • function in information storage (DNA) and transfer (RNA)

  22. “Bases” of DNA & RNA

  23. DNA • deoxyribose sugar • adenine, guanine, cytosine, thymine bases • arranged in a double helix

  24. RNA • ribose sugar • adenine, guanine, cytosine, uracil bases • single-stranded

  25. References • MIT Biology Hypertextbook(1996) http://esg-www.mit.edu:8001/esgbio/lm/sugars/sugars.html (3/9/2001) • Farabee, M.J., (2001) An Online Biology Book. Chemistry 2: Water and Organic Molecules http://gened.emc.maricopa.edu/bio/bio181/BIOBK/BioBookCHEM2.html (3/9/2002) • A.C.D. Labs (2002) ChemSketch (Freeware), available for download at http://www.acdlabs.com/. Used for molecular structure diagrams.

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