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The Chemistry of Life

The Chemistry of Life. Griffy. Atoms. The basic unit of matter Greek, atomos meaning “unable to cut” Named after Democritus...there has to be a limit =atom. Atoms. What does an atom consist of? Subatomic particles: protons (+), neutrons, and electrons (-).

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The Chemistry of Life

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  1. The Chemistry of Life Griffy

  2. Atoms • The basic unit of matter • Greek, atomos meaning “unable to cut” • Named after Democritus...there has to be a limit =atom.

  3. Atoms • What does an atom consist of? • Subatomic particles: protons (+), neutrons, and electrons (-). • What is the center of an atom called? • Nucleus • Where do we find electrons? • Constant motion surrounding the nucleus.

  4. SUBATOMIC PARTICLES • Why are atoms neutral despite having charged particles? • Atoms have equal numbers of electrons and protons/have equal, but opposite charges. (they balance out)

  5. Elements and Isotopes • What is a chemical element? • A chemical element is a pure substance that consists entirely of one type of atom (C, Na, H, N, O, etc.) • What is an isotope? • Atoms of the same element w/ different number of neutrons.

  6. Isotopes of Carbon Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 7 neutrons 6 electrons 6 protons 8 neutrons Because they have the same number of electrons, all isotopes of an element have the same chemical properties.

  7. Chemical Compounds • What is a chemical compound? • Substance formed by the chemical combination of two or more elements. • H20, NaCl, C6H1206

  8. Chemical Bonds • What are the main types of chemical bonds? • Ionic & Covalent • Ionic- electrons transfer from one atom to the other. Sodium atom (Na) Sodium ion (Na+) Chlorine atom (Cl) Chloride ion (Cl-) Transfer of electron Protons +17 Electrons -18 Charge -1 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -17 Charge 0 Protons +11 Electrons -11 Charge 0

  9. Chemical bonds • Covalent Bonds- electrons are shared b/w atoms = molecule. What molecule is this?

  10. Hydrogen Bonds • A single water molecule may be involved in as many 4 hydrogen bonds at the same time. • Cohesion: attraction b/w molecules of the same substance. • Adhesion: attraction b/w different substances. • Meniscus

  11. Properties of Water • Water is polar: there is an uneven distribution of electrons b/w the oxygen and hydrogen atoms. • Why is this important? • Water can react to form ions: H20 -> H+ + OH- Hydrogen ion Hydroxide ion

  12. Acids, Bases, and pH • pH: ranges 0 to 14 • Acids: contain higher [ ] of H+ ions than pure water and have a pH below 7. • Bases: contain lower [ ] of H+ ions than pure water and have pH values above 7.

  13. Buffers • Weak acids or bases that can react w/ strong acids or bases to prevent changes in pH. • Why is this important?

  14. Carbon Compounds • What is the difference b/w organic/inorganic chemistry? • Carbon • Carbon forms strong covalent bonds and can join other carbon atoms to from long chains (carbon-carbon bonds) • Four valence electrons • No others like it.

  15. Macromolecules • Four groups of organic compounds • “Giant molecules” • Carbohydrates (starch and sugar) • Living things main source of energy • Monosaccharide's/polysaccharides, “ose” • Lipids (cooking oil) • Mostly CH, used to store energy • Saturated, unsaturated • Nucleic Acids (RNA & DNA) (CHNOP) • Proteins (polymers of amino acids) (CHNO) • AA are compounds w/an amino group (-NH2) and a carboxyl group (-COOH), what distinguishes each AA?

  16. Amino Acids General Structure

  17. Recognizing Macromolecules Organic or Inorganic? Nucleic Acid Glucose Lipids

  18. Chemical Reactions & Enzymes • Why are chemical reactions important? • Chemical reaction: a process that changes into another set of chemicals. • CO2 + H2O H2CO3 • H2CO3 CO2 + H2O • What are reactants? What are products? • Chemical reactions always involve the breaking of bonds in reactants and the formation of new bonds in products.

  19. Energy in Reactions • To stay alive organisms need to carry out reactions. • Growing, breathing, think, etc. • Activation energy: the energy needed to get a RxN started. • Can you tell which is an energy absorbing reaction/energy releasing reaction?

  20. Enzymes • Some chemical reactions are too slow... • Catalyst: substance that speeds up the rate of a chemical reaction; lowers activation energy • Enzymes (“ase”) are biological catalyst; speed up chemical reactions that take place in the cell. • Lipase • Carbonic anhydrase • Amylase

  21. Enzyme Action • How do they work? • Enzyme-Substrate Complex • The reactants of enzyme-catalyzed reactions are known as substrates. • Not random; active site and substrate fit like “lock and key” • What happens after? • What factors affect enzyme function?

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