Chemistry Notes Anatomy by bhangrawala06


									                            UNIT 2: CHEMISTRY OF LIFE

Energy: No mass; doesn’t take up space
   Kinetic energy: energy of motion
   Potential energy: stored energy
   ATP (adenosine triphosphate): chemical energy used by cells

Matter: has mass; takes up space
   Element: cannot be broken down by common chemical means
   Atom: smallest part of element with all its properties
   Subatomic particles
          o Protons
          o Neutrons
          o Electrons
   Atomic number = number of protons
   Atomic mass number = number protons + neutrons
   Ion: charged atom (unequal number of protons and electrons)
   Isotope: same element with different mass number

   Pure substances
       o Element (atom)
       o Compound (molecule)
   Mixtures
       o Homogeneous
              Solutions
       o Heterogeneous
              Colloids
              Suspensions

   Valence shell: outermost energy level; can hold 8e- (except first)
   Ionic                                       Covalent
        o e- given/taken                              o e- shared
        o conduct elect.                              o doesn’t conduct elect.
        o Crystal lattice

   AB + CD  AD + CB
   Synthesis (anabolic)
   Decomposition (catabolic)
   Replacement (double and single)

Water – 60-80% of volume of cells
   1. high heat capacity prevents sudden changes; helps with homeostasis
   2. high heat of vaporization (ex. Sweating cools us down)
   3. universal solvent (dissolves polar and ionic)
   4. reactivity – involved in hydrolysis reactions (breaking down) and dehydration reactions
        (forming bonds) in carbs and proteins
   5. cushioning – protects from trauma (ex. Brain fluid)

       ionic compounds: cations other than H+, anions other than OH-
       eletrolytes=ions=electrical current in solution
           o ex. NaCl, Ca2CO3, KCl, Ca2(PO4)2

Acids and Bases

Acids                                                     Bases
       sour                                                 bitter
       dissolve metals; corrosive                           feel slippery
       release H+                                           release
       proton donors                                        OH-
       ph <6.5                                              Proton acceptors
                                                             pH >7.5

Neutralization: acid + base  salt + H20
Buffers: regulate pH; resist large pH changes
Strong acids: dissociate completely; low pH; conduct electricity
Strong bases: dissociate easily; high pH; conduct electricity
Weak acids & bases – don’t dissociate well; don’t conduct as well

  1. Carbohydrates – (1-2% cell’s mass); function as fuel, used in making ATPl storage,
     contain C, H, O
        a. Monosaccharides – single ring or chain; monomers
             ex. Glucose, fructose, galactose
        b. Disaccharides – 2 monosacc linked by dehydration synthesis
             ex. sucrose, lactose, maltose
        c. Polysaccharides – long chains
             ex. Starch, glycogen

  2. Lipids – insoluble in H2O; contain C, H, O (but less O than carbs), some have P
        a. Neutral fats (triglycerides) – composed of fatty acids & glycerol; store energy; can
           be saturated or unsaturated
             ex. Butter fat; oil
        b. Phospholipids – diglycerides w/ phosphate group; has hydrophilic head (polar
           phosphate group) and hydrophobic tail (nonpolar fatty acid chains); chief
           component of cell membranes
        c. Steroids – have 4 hydrocarbon rings; used in cell membranes and for vitamin D,
           hormones, and bile salts
             ex. Cholesterol
        d. Eicosanoids – 20 carbon fatty acid derivatives
             ex. Prostaglandins (blood clotting; labor contractions)

  3. Nucleic Acids/Nucleotides – contain C, H, O, N, P; made of nucleotides (sugar,
     phosphate group, nitrogenous base)
        a. DNA – genetic material; double stranded
        b. RNA – gets translated into protein; single stranded
             ex. mRNA, tRNA
        c. ATP – three phosphate groups, sugar, adenine base; cleaving of last phosphate
           group releases energy for use by cells

  4. Proteins – (10-30% of cell mass); contain C,O,H,N and some have S,P; made of amino
     acids; have amine (NH2) and acid (COOH) groups; amino acids are linked by peptide
     bonds; can have over 10,000 aa
        a. Fibrous proteins – extended and strandlike; insoluble in water; very stable; chief
            structural proteins
              ex. Collagen, keratin, elastin
        b. Globular proteins – compact, spherical proteins; water soluble; chemically active;
            functional proteins
              ex. Molecular chaperones – help proteins achieve 3-D structure (heat shock
                   proteins & stress proteins); enzymes; hemoglobin; antibodies
       Protein Structure (conformation)
        Primary – aa sequence
        Secondary – α helix and β pleated sheet
        Tertiary – disulfide bonds; folding; hydrophobic/hydrophilic regions
        Quaternary – 2 or more polypeptide chains join
       Protein Denaturation – unfolding of protein and destruction of 3-D shape
        Caused by excessive heat or pH change
        Affects active site of globular proteins
ENZYMES- speed up reactions by lowering the activation energy (catalyst)
   Activation energy: energy required to start a reaction

Enzyme function
        1. enzymes bind to a substrate (reacting molecule) at its active site
        2. enzyme-substrate rearranges the substrate to form the products
        3. enzyme releases the product; enzyme has not been chnaged

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