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Chapter 2: The Chemistry of Biology

Chapter 2: The Chemistry of Biology. The Composition of the Universe. A. Element : a pure substance that cannot be broken down chemically into other kinds of matter. 1. Ex : Oxygen, Carbon, Hydrogen, Nitrogen, Phosphorus. http://vimeo.com/4433312.

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Chapter 2: The Chemistry of Biology

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  1. Chapter 2: The Chemistry of Biology

  2. The Composition of the Universe A. Element: a pure substance that cannot be broken down chemically into other kinds of matter. 1. Ex: Oxygen, Carbon, Hydrogen, Nitrogen, Phosphorus http://vimeo.com/4433312 http://www.youtube.com/watch?v=d0zION8xjbM&safety_mode=true&persist_safety_mode=1

  3. The Composition of the Universe B. Atom: simplest part of an element C. Subatomic Particles: Parts of an atom 1. Protons: positively (+) charged particles a. Found in the nucleus of an atom 2. Neutrons: neutral particles a. Found in the nucleus of an atom http://www.youtube.com/watch?v=xqNSQ3OQMGI

  4. The Composition of the Universe 3. Electrons: negatively charged particles a. Found moving around the nucleus in energy levels • Each level holds a different number of electrons • 1st level: holds 2 electrons • 2nd level: holds 8 electrons • 3rd level: holds 18 electrons http://www.youtube.com/watch?v=xqNSQ3OQMGI

  5. The Composition of the Universe D. How do you determine the number of protons? 1. Equal to the atomic number E. How do you determine the number of electrons? 1. Equal to the # of protons (atomic number) in a stable atom F. How do you determine the number of neutrons? 1. Equal to the Atomic Mass (rounded) – Atomic #

  6. The Composition of the Universe Carbon • The Electron Energy Levels

  7. Bonding A. All atoms “want” to be stable; if their outermost energy level is not full, then they will tend to undergo reactions to find stability. 1. BONDSare then formed!

  8. Bonding

  9. Bonding • Is it easier for Potassium to gain or lose electrons to have a stable outermost ring of electrons?

  10. Bonding • What about Chlorine?

  11. The Composition of the Universe • Ionic Bonding Results

  12. The Composition of the Universe

  13. Bonding

  14. Bonding + - ATTRACTION OF DIFFERENT CHARGES BETWEEN MOLECULES

  15. Bonding • Ex: Gecko Foot – has half a million hair like projections that are divided into fibers • Forces form between the hairs on the feet and surface allowing the gecko to balance gravity http://www.youtube.com/watch?v=OoYeIsSkafI

  16. Building More Complex Substances B. Building More Complex Substances 1. Compound: substance formed by the chemical combination of atoms from two or more elements a. Ex: H2O (water), C6H12O6 (glucose), CO2 (carbon dioxide) • The properties of the compound are different than those of the elements that create it!

  17. Building More Complex Substances B. Molecule: the simplest form of a compound; when two or more atoms join 1. Ex: O2 (oxygen gas), H2O (water) • *All compounds are molecules, but not all molecules are compounds**

  18. Mixing It Up…Solutions! A. Solution: a mixture in which one or more substances are uniformly distributed in another substance. 1. Two major components a. Solute: substance dissolved into the solution b. Solvent: substance in which the solute is dissolved • Ex: WATER IS THE UNIVERSAL SOLVENT

  19. Mixing It Up…Solutions! B. How do we analyze the strength of a solution? Concentration (amount of solute dissolved in solution) 10g 20g 30g 40g 50g 100mL 100mL 100mL 100mL 100mL

  20. pH Scale A. pH Scale: measures the concentration of hydrogen (H+) ions and hydroxide ions (OH-) in solution • Range of the Scale: 0-14

  21. pH • Acid: • Range: 0-7 • H+ Ions: [High] • OH – Ions: [Low] • Ex: HCl (stomach acid), milk

  22. pH • Base: • Range: 7-14 • H+ ions: [Low] • OH- ions: [High] • Ex: Blood, Ammonia, Sea Water

  23. pH • Neutral: • Range: 7 • H+ ions: [Equal] • OH- ions: [Equal] • Ex: WATER! • What are the strong acids? • What are the strongest bases?

  24. The Chemistry of Water A. COVALENT bonds: join hydrogen and oxygen that make up water 1. Electrons are not shared EQUALLY! a. Oxygenhas 8 electrons b. Hydrogenonly has 1 electron • The oxygen atom pulls the shared electrons towards its own nucleus and away from the hydrogen.

  25. The Chemistry of Water + + B. Polarity: the distribution of charges in atoms joined by a bond 1. Polar compound: a molecule with an uneven pattern of charge or unequal sharing of electrons a. Ex: Water, Sugars, Proteins, DNA (good at dissolving things!) 2. Non-polar compound: a molecule with an even pattern of charge or equal sharing of electrons a. Ex: Oxygen gas, fats, waxes -

  26. Polarity of Water C. Causes water molecules to attract to each otheror be “sticky” and form van der waals forces between them 1. Hydrogen Bond: attraction holding two+ water molecules together a. Positive (H+)region of one water molecule is attracted to the negative (O-) region of another • These are weak bonds; they can be broken easily!

  27. Why is hydrogen bonding important to life and biology? A. Creates cohesion of particles 1. Attractive forces between particles of the same type a. Ex: Water “sticks” allowing striders to move across, Floating a paperclip on water

  28. Polarity of Water • Surface Tension: created by cohesion; a force existing on the surface of a liquid, preventing the layer from being broken http://www.youtube.com/watch?v=8O8PuMkiimg&safety_mode=true&persist_safety_mode=1

  29. Why is hydrogen bonding important to life and biology? B. Creates adhesion of particles 1. Attractive forces between different/unlikesubstances a. Ex: meniscus on a test tube

  30. Why is hydrogen bonding important to life and biology? C. Capillary Action: water molecules move upward through narrow tubes against the force of gravitybecause of cohesion and adhesion 1. Ex: flower, redwood tree

  31. Why is hydrogen bonding important to life and biology? D. High Specific Heat Capacity & Heat of Vaporization: 1. Water must gain or lose large amounts of energy (heat) to break the hydrogen bonds for any temperaturechangeor evaporation to occur. a. Why is this important? • Helps organisms maintain homeostasis • Helps moderate climate/ocean water temperature

  32. Why is hydrogen bonding important to life and biology? E. Water EXPANDS becomes LESS dense when it freezes! 1. Why is this significant? a. Ice floats preventing the water from freezing solid and insulates the lower layers, allowing life to survive underneath it

  33. Penny Lab Video • http://www.youtube.com/watch?v=8O8PuMkiimg&safety_mode=true&persist_safety_mode=1

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