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The CHEMISTRY of LIFE

The CHEMISTRY of LIFE. 6.1 Atoms and their Interactions A. Elements-- cannot be broken down into simpler chemical substances 1. 90 naturally occurring; 25 essential to life 2. CHON= 96% of human body 3. Symbols represent the elements (exms. Ca, C, K, O, P)

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The CHEMISTRY of LIFE

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  1. The CHEMISTRY of LIFE

  2. 6.1 Atoms and their Interactions A. Elements-- cannot be broken down into simpler chemical substances 1. 90 naturally occurring; 25 essential to life 2. CHON= 96% of human body 3. Symbols represent the elements (exms. Ca, C, K, O, P) 4. Trace elements-- vital to cells in small amounts B. Atoms --- smallest particle of an element that has the characteristics of the element. Made up of: 1. Protons--- positive charge 2. Neutrons --- no charge, neutral 3. Electrons--- negative charge 4. Nucleus-- contains protons and neutrons

  3. More stuff on atoms: 5. Atomic #--- number of protons only 6. Atomic Mass--- number of protons PLUS neutrons 7. Electron Energy Levels--- each energy level has a max. # of electrons it can hold. Note: memorize max numbers for levels 1-3 Level 1: 2 electrons Level 2: 8 electrons Level 3: 8 e--’s

  4. C. Isotopes: Same elements but different # of neutrons • Exm. -- Carbon (C12 and C14)-- atomic masses • Note: Both are carbon (atomic # = 6 ) So…. How many neutrons does each have in its nucleus?

  5. Types of Bonds • Note: The goal of every atom is to become more stable by filling up its outer energy level. • 1) Ionic– one atom steals an electron from another • Both atoms become IONS • Example: NaCl • This happens when there is a high electronegativity difference between atoms.

  6. 2) Covalent Bonds= atoms SHARE electrons • Ex. H2 • Types of Covalent bonds: • Polar covalent= electrons shared unequally. ex. H2O • Nonpolar covalent= shared equally. Ex. CH4 • MOLECULE= group of atoms held together by covalent bonds. Has no overall charge.

  7. E. Chemical Reactions • 1. metabolism = all of the chemical reactions that occur in an organism. • Chemical Equations (how we write a chemical reaction) • 1. Reactants-- substances that undergo chemical reaction • 2. Products-- substances formed by the reaction. • 3. Chemical equations must be balanced. • (6 CO2 + 6 H20  C6H12O6 + 6 O2) • Why? -- atoms are neither created nor destroyed in reactions-- just rearranged • Practice-- • __H2 + __O2 ___ H2O • Mixtures and Solutions • 1. Mixture-- a combination of substances in which each substance keeps its original properties. (exm?) • A. Solution-- mixture in which one or more substances are dissolved and evenly distributed in another substance • 1. Solute= dissolved substance • 2. Solvent = substance that dissolves (liquid) • 3. Concentration-- more solute= higher concentration. • Acids and Bases • 1. Acid= pH below 7. Forms hydrogen ions (H+) in water • 2. Base= pH above 7. Forms hydroxide ions (OH-) in water

  8. 6.3 Life Substances • I. Role of Carbon in Organisms (organic chemistry) • A. Carbon has 4 valence electrons available for bonding. (Forms 4 covalent bonds!!) • B. Can form single, double or triple bonds • C. Carbon chains can bestraight, branched or rings.

  9. Legos and Life • Listen for instructions!

  10. II. Formation of Macromolecules • monomers bonded together make polymers. • Condensation or Dehydration Synthesis reactions join monomers together (water is removed, allowing bonds to form) • Hydrolysis breaks down polymers into monomers. (water is added, breaking bonds)

  11. III. The 4 most important types of biological Macromolecules • Carbohydrates • Lipids • Proteins • Nucleic Acids

  12. Carbohydrates (good energy source) 2:1 ratio of hydrogen to oxygen. Functions/ uses energy storage and release structure (ex. Cellulose/plant fiber)

  13. Monosaccharides= general formula= CH2O glucose (C6 H12 O6)—blood sugar, made by plants in photosynthesis fructose (C6 H12 O6)—fruit sugar galactose (C6 H12 O6)--- part of milk sugar Disaccharides …formula = C12H22O11 (why?) Sucrose= glucose and fructose maltose= glucose and glucose lactose= glucose and galactose Carbohydrates continued…

  14. Polysaccharides (formed by dehydration synthesis) • starch= food storage in plants • glycogen= food storage in animals, highly branched • cellulose= plant cell walls, plant fiber • chitin = exoskeletons, structure in certain animals

  15. Lipids (energy storage, organ cushioning, insulation) • Lipids are insoluble in water because their molecules are nonpolar (not attracted by water molecules) or hydrophobic! • Fats and oils • glycerol and 3 fatty acid tails (chains of C and H) • unsaturated fats (oils). Have double bonds. • saturated fats. No double bonds. Saturated with HYDROGEN

  16. Lipids Continued… • Phospholipids • glycerol with 2 fatty acid tails and one phosphate. • Make up cell membranes! • fatty acid tails= hydrophobic • phosphate head = hydrophilic • steroids • cholesterol • hormones like testosterone and estrogen

  17. Proteins • Proteins—large complex polymers composed of carbon, hydrogen, oxygen, nitrogen (and sometimes sulfur.) • amino acid = Monomer (there are 20 amino acids—each one has a different R group—variable group)

  18. Proteins continued… • Polypeptide= a polymer (chain) of amino acids • peptide bonds between amino acids formed by _______ ______. • the number and order of amino acids determines the kind of protein • chain folds to make a 3-D structure—This determines the protein’s function. • denature= mess up 3-D structure. Protein loses its function due to heat, pH changes etc. • Several polypeptides may group up to form one protein (ex. Hemoglobin)

  19. Proteins are essential to life • Structural—keratin= hair, nails, horns, hoofs etc, collagen… • Muscle contraction • Transport (ex. Hemoglobin) • Transport across cell membranes • immune system (antibodies) • Enzymes… (more detail on next slide…)

  20. Digestion Example Enzymes • Proteins that change rate of chemical reactions • involved in nearly all metabolic processes • substrate= substance that the enzyme acts on. • Fits into active site of enzyme • Product • coenzymes= vitamins, cofactors= minerals… help enzymes function Animation C:\Documents and Settings\BBAUGHMAN\Desktop\bio powerpoints\Chapter 06 BDOL IC

  21. Nucleic Acids • DNA and RNA • used as patterns for making proteins • Monomer = nucleotide • sugar • phosphate • nitrogen base • adenine pairs with thymine (or uracil in RNA) • guanine pairs with cytosine • nitrogen bases that pair up are called complementary • DNA Replication showing base pairing C:\Documents and Settings\BBAUGHMAN\Desktop\bio powerpoints\Chapter 11 BDOL IC

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