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CHAPTER 2 CHEMISTRY OF LIFE

CHAPTER 2 CHEMISTRY OF LIFE. CPI Tyska Holliston HS. Section 2-1 The Nature of Matter. Atoms. An atom is the simplest unit of matter. SUBATOMIC PARTICLES : ________________________ ________________________ ________________________ NUCLEUS: made up of protons + neutrons.

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CHAPTER 2 CHEMISTRY OF LIFE

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  1. CHAPTER 2CHEMISTRY OF LIFE CPI Tyska Holliston HS

  2. Section 2-1 The Nature of Matter Atoms • An atom is the simplest unit of matter. • SUBATOMIC PARTICLES: • ________________________ • ________________________ • ________________________ • NUCLEUS: made up of protons + neutrons

  3. ATOMIC STRUCTURE 3 SUBATOMIC PARTICLES: • ________________: positive (+) charge, located in nucleus • ________________: neutral charge, located in nucleus • ________________: negative charge (-) , outside nucleus in energy levels

  4. Atoms - The Nucleus Nucleus • Contains protons (+) and neutrons (no charge) • Most of mass concentrated in nucleus • # of protons = ___________________

  5. The ATOM • All atoms are NEUTRAL (= number of protons and electrons) • ____________________________= # of protons • ____________________________= # of protons + neutrons Two simplified models of a helium (He) atom

  6. electron proton SODIUM 11p+ , 11e- CHLORINE 17p+ , 17e- neutron CARBON 6p+ , 6e- OXYGEN 8p+ , 8e- NEON 10p+ , 10e- HYDROGEN 1p+ , 1e- HELIUM 2p+ , 2e-

  7. Elements • _____________________________: a pure substance that cannot be chemically broken down into simpler kinds of matter. • Over 100 identified; less than 30 important to living things • ________________________: 1 or 2 letters that represent each element (ex) C = carbon, He = helium • ______________________________: determines number of protons in the element

  8. ~96% = __________________

  9. http://www.corrosionsource.com/handbook/periodic/

  10. ISOTOPES • ________________:elements with same # of protons but different # of neutrons • Example: carbon has 3 isotopes 12C = 6p + 6n 13C = 6p + 7n 14C = 6p + 8n

  11. Figure 2-2 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, these isotopes of carbon have the same chemical properties. The difference among the isotopes is the number of neutrons in their nuclei.

  12. _______________________________________________: nuclei are unstable and break down at a constant rate over time  radiation given off can be dangerous but also useful • PET SCAN: • Radioactive isotope is injected into the patient • patient moves through pet scan • cells absorb isotope at different rates • scanner detects radiation  forms image

  13. Compounds • ___________________________________: substance formed by the chemical combination of 2 or more elements in definite proportions • ___________________________________: represents a compound • (ex) water = H20 • Physical & Chemical properties in a compound differ from those of elements: • Ex.) Table salt (NaCl) • Na (Sodium) is a silver-colored metal • Cl (Chlorine) is a poisonous greenish gas

  14. Compounds • Most atoms are not stable in their natural state. • Atoms tend to react, or combine in ways to make them more stable. • Chemical bonds are broken • Atoms are rearranged • New chemical bonds are formed • ________________: smallest unit of most compounds

  15. MAJOR BONDS IN BIOLOGICAL MOLECULES • _______________________: forms when one or more electrons are transferred from 1 atom to another • __________________________:forms when electrons are shared between atoms

  16. IONIC BONDING – table salt, NaCl is an example ________________________________: an atom that has lost an electron (ex) sodium ion _________________________________: an atom that has gained an electron (ex) chlorine ion

  17. IONIC BONDING – electron transfer A sodium chloride crystal Common ions in organisms: Na+, Cl-, K+, Ca2+, Mg2+

  18. COVALENT BONDING – OXYGEN Two oxygen atoms, each with eight protons, share four electrons in a double covalent bond. molecular oxygen (O2) O=O Two lines represent 2 electron pairs in a double covalent bond.

  19. COVALENT BONDING – WATER Oxygen has vacancies for two electrons in its highest energy level orbitals. Two hydrogen atoms can each share an electron with an oxygen. The resulting two POLAR covalent bonds form a water molecule. - + + water (H2O) H—O—H In a polar bond, atoms do not share electrons equally. Fig. 2-8b(3), p.25

  20. Van der Waals Forces • Rapidly moving electrons cause momentary tiny (+) or (-) charges on molecules • Rapid, slight attraction between these regions on neighboring molecules Van der Waals forces halp geckos to grip smooth, vertical surfaces.

  21. THE IMPORTANCE OF WATER • cells ________________ water –medium of life • dominates climate • covers _______________ of earth’s surface • common as gas, liquid, & solid in nature • life began in water 2-2 Properties of Water

  22. The Water Molecule • ________________: uneven distribution of electrons between the O and H atoms • O is slightly (____), H is slightly (___)

  23. Hydrogen Bonds • H on one H2O is attracted to _________________ on a different H2O • 1 H2O can have ______ H-bonds at a time

  24. STRUCTURE OF WATER • partial + and – ends • max 4 weak H-bonds

  25. COHESION • An attraction between molecules of the ________________________________________ • sticking together of water molecules due to H- bonds • creates high surface tension in water • important in water rising through stems in xylem vessels Water strider is able to walk on water due to water’s high surface tension.

  26. ADHESION • attraction between molecules of ______________________________________________ • ability to “wet” • important in water rising through stems in xylem vessels by helping counter downward gravity pull

  27. MIXTURES & SOLUTIONS • ________________ – composed of 2 or more elements or compounds that are physically mixed together but not chemically combined • ________________ – type of mixture in which 2 or more substances are evenly distributed throughout • ________________ – the dissolving agent • ________________ – substance that is dissolved

  28. Solutions & Suspensions • ________________: mixture of water and nondissolved material • ________________: solution where water is the solvent Cl- Cl- Na+ Na+ Water Water

  29. ACIDS & BASES • _______________________: any compound that forms H+ ions in solution; tend to me be sour and corrosive • ________________________: compound that produces hydroxide ions [OH+] in a solution; tend to be bitter and slippery • ________________________: measurement system to indicate the concentration of H+ ions in solution

  30. pH SCALE • scale from 0 to 14 • ________________: have pH below 7 • ________________: have pH above 7 • most biological fluids have pH 6-8 (neutral) • pH scale differs by factor of 10 in [H+] therefore a small change in pH causes a large change in [H+]

  31. BUFFERS • weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH • (ex) buffer system in blood to keep acid and base in equilibrium • buffering system = __________________

  32. ACID PRECIPITATION • threatens fitness of environment • acid precipitation: pH <5.6 • causes: acids released by combustion of fossil fuels and car exhaust Acid rain damage to statuary, 1908 & 1968

  33. The Chemistry of Carbon • 4 valence electrons • Can covalently bond with many diff. atoms • Chains of carbon atoms Section 2-3 Carbon Compounds

  34. Macromolecules • Giant molecules • ________________: smaller units • ________________: large compound made from many monomers • 4 groups of organic compounds found in living things: • ________________ • ________________ • ________________ • ________________

  35. OVERVIEW of ORGANIC COMPOUNDS DEHYDRATION SYNTHESIS HYDROLYSIS

  36. Carbohydrates • C:H:O in a 1:2:1 ratio • Main source of energy • Also used for structural purposes • ____________________________– single sugar molecules • ____________________________– many sugar molecules (Starch, glycogen, cellulose)

  37. MONOSACCHARIDES Galactose Glucose

  38. Glucose monomer & disaccharides Glucose monomer Sucrose Maltose

  39. STARCH is composed of glucose monomers Starch Glucose _________________________________: stored excess sugar in animals (animal starch) __________________________________: stored excess sugar in plants

  40. CELLULOSE • another polysaccharide made by plants made of long microfibrils of glucoses • gives strength & rigidity in plant cell walls • major component of wood • most abundant organic compound on earth

  41. LIPIDS • Made from carbon and oxygen • Not soluble in water (fats, oils, waxes) • Glycerol + 3 fatty acids • _____________________________________: all single bonded carbons, solid at room temperature (butter) • _____________________________________: at least one carbon-carbon double bond, liquid at room temp (olive oil)

  42. The synthesis and structure of a fat

  43. FAT FUNCTIONS • __________________: FAT 9.3 kcal/g • CARB. 3.79 kcal/g • PROTEIN 3.12 kcal/g • _________________: protects internal organs • _________________________________: insulates body under skin (blubber) • ___________________________: coating on skin, fur, feathers, leaves, fruits exoskeletons

  44. SATURATED VS UNSATURATED FATS ________________________________ FATS: FA’S all single bonds; mostly animal fats; associated with unhealthy diet  risk of artherosclerosis, plaques in bv’s reduce blood flow ________________________________ FATS: FA’S have double bonds which causes links; oils at room temp (plants, fish) ________________________________ FATS: many double bonds (cooking oils)

  45. Saturated & Unsaturated Fats & Fatty Acids 

  46. Nucleic Acids • Made from C, O, H, N, & P • Store and transmit genetic information • _____________________________________ monomers, consisting of 3 parts: • 5-carbon sugar • Phosphate group • Nitrogenous base • ________________ (Ribonucleic acid) • ________________ (Deoxyribonucleic acid)

  47. NUCLEOTIDE • Monomer made of three parts: • ____________________ • ____________________ • ____________________ DNA – formed from 2 chains of nucleotides

  48. STRUCTURE OF NUCLEIC ACID covalent bonds link nucleotides between phosphate group and sugar

  49. Proteins • ________________: polymers composed of amino acids; made of C, O, H, N • ________________: monomers that make up proteins; contain an amino group (-NH2) and a carboxyl group (-COOH) • >20 different amino acids found in nature • Different _________________________ (random side-chains coming off of each amino acid)

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