Molecules of Life – Biomolecules - PowerPoint PPT Presentation

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Molecules of Life – Biomolecules

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  1. Molecules of Life – Biomolecules

  2. What Do These Pictures Have in Common?

  3. Brain Tissue

  4. Protein Structure – the correct protein structure is important for normal function

  5. Prions Dr. Stanley Prusiner.

  6. Why Is Carbon So Important?Organic/Inorganic Molecules • Organic vs. Inorganic in Chemistry • Organic refers to molecules containing a carbon skeleton • Inorganic refers to carbon dioxide and all molecules without carbon

  7. Carbon’s Versatility • Carbon atoms are versatile and can form up to four bonds (single, double, or triple) and rings • Functional Groups in organic molecules confer chemical reactivity and other characteristics • Determines how that molecule will function (For ex. whether it is polar [charged] or nonpolar [uncharged])

  8. Common Elements Found in Living Organisms • Carbon (C) • Hydrogen (H) • Nitrogen (N) • Oxygen (O) • Phosphorous (P)

  9. Organic Molecule Synthesis • Biomolecules are polymers (chains) of subunits called monomers

  10. Dehydration Synthesis • Monomers are joined together through dehydration synthesis • An H and an OH are removed, resulting in the loss of a water molecule (H2O)

  11. Hyrolysis • Polymers are broken apart through hydrolysis (“water cutting”) • Water is broken into H and OH and used to break the bond between monomers

  12. Biological Molecules • All biological molecules fall into one of four categories • Carbohydrates • Lipids • Proteins • Nucleic Acids

  13. 1. Carbohydrates • Carbohydrate composition • Made of C, H, and O in the ratio of 1:2:1 • Construction • Simple or single sugars are monosaccharides • Two linked monosaccharides are disaccharides • Long chains of monosaccharides are polysaccharides

  14. Carbohydrates • Carbohydrates are important energy sources for most organisms

  15. Monosaccharides • Basic monosaccharide structure • Backbone of 3-7 carbon atoms • Many –OH and –H functional groups • Usually found in a ring form in cells • Example monosaccharides • Glucose (C6H12O6): the most common

  16. Monosaccharides • Fate of monosaccharides inside a cell • Some broken down to free their chemical energy • Some are linked together by dehydration synthesis for storage

  17. Disaccharides • Disaccharides are two-part sugars • Sucrose (table sugar) = glucose + fructose • Lactose (milk sugar) = glucose + galactose • Maltose (malt sugar)= glucose + glucose

  18. Polysaccharides Used For Energy Storage • Monosaccharides are linked together to form chains (polysaccharides) • Storage polysaccharides • Starch (polymer of glucose) • Formed in roots and seeds as a form of glucose storage • Glycogen (polymer of glucose) • Found in liver and muscles

  19. Polysaccharides Used For Structural Support • Structural polysaccharides • Cellulose (polymer of glucose) • Found in the cell walls of plants • Indigestible for most animals due to orientation of bonds between glucoses

  20. Polysaccharides Used For Structural Support • Structural polysaccharides continued • Chitin (polymer of modified glucose units) • Found in the outer coverings of insects, crabs, and spiders • Found in the cell walls of many fungi

  21. 2. Lipids • All lipids contain large chains of nonpolarhydrocarbons (a chain of carbon atoms w/hydrogen atoms attached) • Most lipids are hydrophobic (don’t like water) and water insoluble (don’t dissolve in water) • Lipids are diverse in structure and serve in a variety of functions • Energy storage • Waterproofing • Membranes in cells • Hormones

  22. 3 Groups of Lipids • 1. Oils, fats, and waxes • 2. Phospholipids • 3. Steroids

  23. Oils, Fats, and Waxes • Made of only C, H, and O • Made of one or more fatty acid subunits • Long chains of C and H with a carboxylic acid group (-COOH) at one end • Fats and oils • Formed by dehydration synthesis

  24. Oils and Fats • Fats and oils used for long-term energy storage • Fats and oils possess a high density of stored chemical energy

  25. Oils and Fats • Fat solidity is due to single or double carbon bonds • Fats that are solid at room temperature are saturated (carbon chain has as many hydrogen atoms as possible, and mostly or all C-C single bonds), e.g. beef fat

  26. Oils and Fats • Fat solidity is due to single or double carbon bonds (continued) • Fats that are liquid at room temperature are unsaturated(fewer hydrogen atoms, many C=C double bonds), e.g. corn oil

  27. Waxes • Composed of long hydrocarbon chains and are strongly hydrophobic • Highly saturated and solid at room temperature • Form waterproof coatings • Used to build honeycomb structures

  28. Phospholipids • Form plasma membranes around all cells • Phospholipids have hydrophobic and hydrophilic portions • Polar functional groups are water soluble • Nonpolar fatty acid “tails” are water insoluble

  29. Steroids • Steroids are composed of four carbon rings fused together • Examples of steroids • Cholesterol • Found in membranes of animal cells • Male and female sex hormones

  30. 3. Proteins • Proteins have a variety of functions • Enzymes catalyze (speed up) reactions • Structural proteins (e.g. collagen) provide support

  31. Amino Acids • Proteins are formed from chains of amino acids (monomers) • There are 20 amino acids that make up proteins of living things.

  32. Amino Acids • All amino acids have similar structure • Central carbon atom bonded to four different functional groups • 1. An amino group (-NH2) • 2. A carboxylic acid group (-COOH) • 3. A hydrogen (H) • 4. All have a variable “R” group • Some R groups are hydrophobic • Some are hydrophilic • Cysteine R groups can form disulfide bridges

  33. Amino Acids • The sequence of amino acids in a protein dictates its function

  34. Dehydration Synthesis • Amino acids are joined to form chains by dehydration synthesis • An amino group reacts with a carboxyl group, and water is lost

  35. Dehydration Synthesis • Resultant covalent bond is a peptide bond • A chain of two amino acids or a short amino acid chain is called a peptide • Long chains of amino acids are known as polypeptides or just proteins

  36. Three Dimensional Structures • The type, position, and number of amino acids determine the structure and function of a protein • Precise positioning of amino acid R groups leads to bonds that determine structure • Disruption of these bonds leads to denatured proteins and loss of function • For ex. If you expose a protein to high temperatures, it will cause the protein to unfold, in other words, to denature.