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Chapter 2

Chapter 2. The Chemistry of Life. The 4 organic molecules found in living things. Carbohydrates = C-H-O Lipids = C-H-O Nucleic Acids = P-C-H-O Proteins = N-H-O-C. Chemistry. What is the chemistry of “life”?.

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Chapter 2

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  1. Chapter 2 The Chemistry of Life

  2. The 4 organic molecules found in living things Carbohydrates = C-H-O Lipids = C-H-O Nucleic Acids = P-C-H-O Proteins = N-H-O-C

  3. Chemistry What is the chemistry of “life”? • Twenty-five chemicals are necessary for life and four elements create about 96 % of living matter: • Carbon • Oxygen • Hydrogen • Nitrogen. • COHN • The Atom and Periodic Table • http://www.classzone.com/books/earth_science/terc/content/investigations/es0501/es0501page01.cfm

  4. Atoms Democritus coined the term atom 2500 years ago 1. What is an atom made of? 2. What is atomic number? 3. What is atomic mass? 4. Determining the # of electrons? 5. What are the valence electrons? Electrons, Protons, Neutrons # of protons Average number of protons & neutrons Balanced atoms

  5. Isotopes & Element Isotope - different number of neutrons Do isotopes act differently in chemical reactions? How are radioactive isotopes used? (Geological Dating, Bacteria, Cancer, Tracers or Markers) What is an element? 1. An material which cannot be broken down or changed into another substance using chemical means. The basic chemical building blocks of matter. What makes elements different from each other? 1. The number of protons in the nucleus

  6. Forces of Nature 4 Forces • Electromagnetism • Strong Nuclear Force between protons & neutrons • Weak Nuclear Force – decay of an atom (alpha, beta, gamma) • Gravity – the force exerted between two objects • God Particle • http://www.economist.com/node/21541797

  7. RadioactiveDecay 1. Alpha Decay alpha particle emitted = (2 protons and 2 neutrons) 2. Beta Decay A . Beta Minus - Neutron turns into a proton + electron + antineutrino – Last two emiited B. Beta Plus - Neutron turns into a proton + positron + neutrino – last two emitted 3. Gamma Decay – nucleus emits photons Nucleus moving from high to lower state of energy

  8. Compounds & Bonds Compounds - two or more elements chemically bonded Molecule - smallest unit of a compound that is still exhibiting the compounds properties Ionic Bonds - transfer of electrons - resulting in ions (cations and anions) Covalent Bonds - shared pairs of electrons - electronegativity What are Valence Electrons & what does stable mean?

  9. Electronegativity

  10. Variances in charges causing attraction & weak bonds Geckos and surface area in their feet http://www.youtube.com/watch?v=iCSiipjptfA Van der Waals Forces

  11. Water What makes water so great? Hydrogen Bonding http://www.youtube.com/watch?v=lkl5cbfqFRM&feature=related

  12. Properties of Water – Blue Planet – ever wonder why? Density Polarity Hydrogen Bonds High Specific Heat Capacity: 1g H2O/1degree celsius Cohesion Adhesion Universal Solvent Mixture - two or more elements not chemically combined Solution - Universal Solvent - ions disperse Suspensions - blood - movement keeps larger particles afloat throughout the fluid

  13. What is the pH scale? A scale from 0 to 14 reflecting the concentration of hydrogen ions in solution; pure water has a pH value of 7, acids have a lower value and bases higher. • pH levels affect the conformational state (optimum 3D formation) of the enzyme. • What is an acid and what is a base? • Acids are compounds that contain hydrogen and can dissolve in water to release hydrogen ions into solution. • HCl disolved in H2O = H+(aq)  +  Cl-(aq) • Bases are compounds that dissolve in water to release hydroxide ions (OH-) into solution. • NaOH dissolved in H2O = Na+(aq)  +  OH-(aq) • What is a buffer? A buffer resists changes in pH when small quantities of an acid or a base are added to it. pH - "Potential Hydrogen”

  14. pH & Blood - buffering • Your blood's pH is normally at 7.4 • Lungs – carbon dioxide (CO2) • Kidneys - bicarbonate (HCO3) ammonia (NH3) / ammonium (NH4+) • Alkalosis • pH rises above 7.45 • Too Little CO2 & Too Much HCO3 • Associated with electrolyte disturbances caused by prolonged vomiting, severe dehydration, or hyperventilation • Low carbonic acid concentrations interpreted as a sign of high oxygen levels, so it constricts blood vessels to reduce oxygenation. • H+(aq) + HCO3-(aq) ↔ H2CO3(aq) – carbonic acid • Acidosis • pH falls below 7.35 • Too much CO2 & Too Little HCO3 • High carbonic acid concentrations interpreted as a sign of low oxygen levels, so it dilates blood vessels to improve oxygenation. • CO2(aq) + H2O(l) ↔ H2CO3(aq) • The HCO3 (base) / CO2 (acid) buffer system is extremely important because it can be rapidly readjusted in alkalosis and acidosis

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