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The Chemical Composition of Cells

The Chemical Composition of Cells. Chapter 2. Learning Objectives- 1. Understand the Structure of the Molecular Components of Living Organisms Carbohydrates, which supply and store energy and serve as structural building blocks, include sugars and polymers of sugars.

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The Chemical Composition of Cells

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  1. The Chemical Composition of Cells Chapter 2

  2. Learning Objectives- 1 • Understand the Structure of the Molecular Components of Living Organisms • Carbohydrates, which supply and store energy and serve as structural building blocks, include sugars and polymers of sugars. • Proteins, which catalyze reactions and are structural building blocks, are polymers of amino acids. • The nucleic acids DNA and RNA, which code and express genetic information, are polymers of nucleotides. • Lipids are membrane components consisting mainly of carbon and hydrogen atoms derived from acetates and other molecules. • Secondary metabolites such as phenolics, alkaloids, and terpenoids often protect or strengthen plants.

  3. Learning Objectives -2 • To Understand Energy and Chemical Reactions • Energy can be stored and can move or change matter . • Chemical reactions involve either a net input or a net output of free energy. • The movement of electrons is the basis of energy transfer through oxidation and reduction reactions. • The terminal phosphate bond in ATP releases energy when broken. • NADH, NADPH, and FADH2 are universal carriers of energy-rich electrons in living organisms.

  4. Learning Objectives -3 • To Understand the Nature of Chemical Reactions and Enzymes • Enzymes position reactants, allowing reactions to occur with minimal activation energy or increase in temperature. • Cofactors such as coenzymes interact with enzymes to assist reactions and indirectly provide energy in the form of electrons for biochemical reactions. • Competitive and noncompetitive inhibition can slow or stop enzymatic reactions and pathways. • Enzymatic reactions are linked together into metabolic pathways.

  5. Learning Objective • Know the basic structure of atom, and know the role of ionic, covalent and hydrogen bonds.

  6. Key Terms: Atoms • Proton • positive electric charge, small mass • Neutron • uncharged, about same mass as proton • Electron • negative charge, extremely small mass

  7. A Carbon Atom

  8. Electrons • Move around the nucleus at different energy levels • Allow elements to combine chemically to form chemical compounds • Ions are atoms which tend to gain or lose electrons

  9. Electron Configurations

  10. Acids and Bases • Acids dissociate in water to form hydrogen ions (protons, H+) • Bases dissociate in water to yield negatively charged hydroxide ions (OH-)

  11. pH Scale • A measure of the relative concentrations of H+ and OH- in a solution • A solution’s acidity or alkalinity is expressed in terms of the pH scale

  12. KEY TERMS • IONIC BOND • An electrostatic attraction between oppositely charged ions

  13. Ionic Bonding

  14. KEY TERMS • COVALENT BOND • A chemical bond involving one or more shared pairs of electrons

  15. Covalent Bonding in Hydrogen

  16. Covalent Bonding in Methane

  17. KEY TERMS • HYDROGEN BOND • An attraction between a slightly positive hydrogen atom in one molecule and a slightly negative atom (usually oxygen) in another molecule

  18. Animation: How Atoms Bond CLICKTO PLAY

  19. LEARNING OBJECTIVE • Discuss the properties of water, and explain the importance of water to life

  20. Water • Has a strong dissolving ability • Molecules form hydrogen bonds with one another (cohesion) • Molecules form hydrogen bonds to substances with ionic or polar regions (adhesion) • Adhesion & Cohesion are particularly important for transport • All living things require water to survive • Almost all chemical reactions that sustain life occur in aqueous solution • High Melting & Freezing Points • Insulation Property after freezing (e.g., lakes)

  21. Water Structure

  22. Animation: Structure of Water CLICKTO PLAY

  23. LEARNING OBJECTIVE • Describe the chemical compositions and functions of carbohydrates, lipids, proteins, and nucleic acids

  24. KEY TERMS • CARBOHYDRATE • An organic compound containing carbon, hydrogen, and oxygen in the approximate ratio of 1C:2H:1O

  25. Carbohydrates 1 • Include sugars, starches, cellulose • Important fuel molecules, components of molecules (nucleic acids) and cell walls

  26. Carbohydrates 2 • Monosaccharides • simple sugars • Disaccharides • two monosaccharide units • Polysaccharides • many monosaccharide units

  27. Common Monosaccharides

  28. Sucrose Synthesis

  29. Starch: A Storage Polysaccharide

  30. Cellulose: A Structural Polysaccharide

  31. KEY TERMS • LIPID • Any of a group of organic compounds that are insoluble in water but soluble in fat solvents

  32. Lipids 1 • Have a greasy consistency, do not readily dissolve in water • Important fuel molecules, components of cell membranes, waterproof coverings over plant surfaces, light-gathering molecules for photosynthesis

  33. Lipids 2 • A neutral fat or oil molecule is composed of a molecule of glycerol plus one, two or three fatty acids

  34. Formation of a Neutral Fat or Oil

  35. KEY TERMS • PROTEIN • A large, complex organic compound composed of amino acid subunits

  36. Protein • A macromolecule composed of amino acids joined by peptide bonds • Order of amino acids determines structure and function of a protein molecule • Enzymes: Proteins that increase the rate of chemical reactions

  37. Amino Acids

  38. Peptide Bonds

  39. Protein Synthesis Animation • http://www.wisc-online.com/objects/index_tj.asp?objid=AP1302

  40. Organization of Protein Molecules

  41. KEY TERMS • NUCLEIC ACID • Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) • Large, complex organic molecules composed of nucleotides

  42. Nucleic Acids • Control the cell’s life processes • Deoxyribonucleic acid (DNA) • Transmits information from one generation to the next • Ribonucleic acid (RNA) • Involved in protein synthesis

  43. Nucleotides • Repeating units that form nucleic acids • Order of nucleotides in a nucleic acid chain determines the specific information encoded • Adenosine triphosphate (ATP) • A modified nucleotide compound important in energy transfers in biological systems

  44. Nucleic Acids

  45. Nucleic Acids

  46. Nucleic Acids

  47. DNA Replication Animation • http://www.visionlearning.com/library/module_viewer.php?mid=63&l=&c3=

  48. KEY TERMS • ADENOSINE TRIPHOSPHATE (ATP) • An organic compound of prime importance for energy transfers in biological systems

  49. ATP • ATP is a nucleotide that performs many essential roles in the cell. • It is the major energy currency of the cell, providing the energy for most of the energy-consuming activities of the cell. • It is one of the monomers used in the synthesis of RNA and, after conversion to deoxyATP (dATP), DNA. • It regulates many biochemical pathways.

  50. LEARNING OBJECTIVE • Discuss the role of enzymes in cells

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