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Biochemistry

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					            Unit 2 - Biochemistry
I. Chemical level
  A.           Basic definitions
       1.      Matter –  Anything that has mass and
                         occupies space
       2.      Element - Basic unit of all
                         matter (109 +)
              a.   92 naturally occurring elements
              b.       Four basic elements for life – H,
                   C, O, N (96% of human mass)
                      Ca, P (additional 3%)
                      K, S, Cl, Mg, I, Fe, Na, along
                      with others (additional 1%)
c.    Atomic Structure

      1.   Nucleus – protons (p+) and
      neutrons (no)




     2.   Electron cloud – outside of
     nucleus
  d.    Atomic # tells us the # of protons




  e.    In a neutral atom, #p+ = #e-

  f.    The atomic mass tells us the weighted
average of the element’s isotopes in atomic mass
                     units.

Isotopes – Atoms of the same element that have the
same number of p+ but a different # of no

       For each isotope, the atomic mass is the
                  # of p+ + # of no
g.   Electrons in energy levels – 2, 8, 18, etc.
      1.   Electrons may gain energy and jump to a
      higher level

      2.    If the outer levels (valence) of the
      electron cloud fill, an atom is more stable
      chemically

B. Bonding – Giving/receiving or sharing
of valence electrons through a chemical
reaction. Main types:
 1.   Ionic –   One atom gains electrons, another
                loses
      This transfer of e- results in an atom that
      carries a charge = ION
CATION - A positively charged ion that results
         when a metal loses e-
ANION - A negatively charged particle that
        results when a nonmetal gains e-

Electrolytes – Ionic solutions
2.   Covalent – More common in the human body,
                more stable
     Result from sharing of 1-4 pairs of e-. EX:
3.   Hydrogen Bond - Weak bridges between molecules
                     that contain hydrogen covalently
                     bonded to O or N
a.   Only 5% as strong as a covalent bond

b.   Break and form easily
c.   Found in H2O, proteins, and nucleic acids
C.    Types of Reactions
      1.    Synthesis reaction – Anabolic
           A + B         AB
           (Reactants)          (Products)
     http://www.dlt.ncssm.edu/core/Chapter5-Moles-Molarity-
     Reaction_Types/Chapter5-Animations/Synthesis.html

      2.     Decomposition - Catabolic

      AB                          A + B
      (Reactants)                  (Products)

     http://www.dlt.ncssm.edu/core/Chapter5-Moles-Molarity-
     Reaction_Types/Chapter5-Animations/Decomposition.html
3.    Exchange (Replacement) – Single or Double

             AB + C               AC + B

     http://www.dlt.ncssm.edu/core/Chapter5-Moles-
     Molarity-Reaction_Types/Chapter5-
     Animations/SingleDisp_Reaction-MetalToAcid.html


           AB + CD               AD + CB

     http://www.dlt.ncssm.edu/core/Chapter5-Moles-
     Molarity-Reaction_Types/Chapter5-
     Animations/DoubleDisp_Reaction-Precipitation.html
II. Chemical Compounds and Life Processes
 A. Inorganic Compounds – Usually lack
 carbon, relatively small
   1.     H2O – Most abundant inorganic substance in a
   human
      a.    60% of red blood cells
      b.    75% of muscle
      c.    92% of plasma
      d.    Solvent – liquid or gas that another
                      substance dissolves in, H2O is
                      the Universal Solvent
       e.   Absorbs and releases heat slowly – helps in
       maintaining homeostasis
       f.   Lubricant – saliva, mucus
       g.   Suspension medium
2.   Acids – dissociates into H+ and an anion
     HNO3  H+ + NO3-
3.   Bases – dissociate into OH- and a cation

      NaOH  Na+ +       OH-

4.   Salts – ionize to form anions and cations

      NaCl  Na+ + Cl-
5.    pH – degree of acidity or alkalinity of a
solution
         H+ = OH- neutral
         H+ > acidic
         OH- > basic
                        pH Scale

     0-------------------------7-------------------------14
   Many H+              H+ = OH-                   Many OH-
   Few OH-                                         Few H+
                        Neutral
   Acidic                                           Basic

6.    Buffer System – Maintains the body’s pH
by replacing strong acids and bases with weak
acids and bases
D. Organic Compounds – Always contain
carbon, covalent
 1.        Carbohydrates - Contain C, H, O
      a.      Sugars – Based on the # of sugars
                       (saccharides), used for energy
                       storage, can be “burned” to
                       produce water, carbon dioxide and
                       energy.
           * Monosaccharides (3-7 carbons), C:H:O=1:2:1
                EX: Glucose, fructose, ribose, and
                pentose (deoxyribose)

           *Disaccharides – sucrose, galactose, maltose
                Two simple sugars bond through a
                dehydration synthesis (loss of water) =
                GLYCOSIDIC LINKAGE
Glucose + Fructose = Sucrose
Glucose + Glucose = Maltose
Glucose + Galactose = Lactose
b.    Polysaccharides – made up of many glucoses in
a chain or branching chain. Starch (plants), glycogen
(animals)
Polysaccharides are
broken apart by
hydrolysis = addition
of water
2.   Lipids – C,H,O – no fixed ratio, most are not
water soluble (Hydrophobic)
   a.    Triglycerides – two basic components are the
   glycerol backbone and fatty acids
*harder to break down than carbs but provide 2X
the energy of carbs or proteins
*Saturated – single bonds between carbons, all C are
bonded to a maximum number of H ( beef, pork,
butter, whole milk, eggs, cheese) the liver produces
cholesterol form the breakdown of
*Monounsaturated – 1 double
covalent bond between
carbons (olive oil, peanut oil)
help reduce cholesterol
*Polyunsaturated – more
than 1 double bond (corn
oil, safflower, sunflower,
cottonseed, sesame,
soybean) help reduce
cholesterol
b.   Phospholipids – one saturated, one
unsaturated F.A., 3rd F.A. replaced with phosphate.
Amphipathic – one end of the molecule is
              hydrophilic = (water loving)
                 The other end is hydrophobic =
                 (water fearing)
Phospholipids are important to structure of plasma
                    membrane
3.        Proteins – C,H,O,N
     a.     Body structure, physiological activity (catalysts)
b.    Made up of building blocks known as amino
acids (20 different)
Each amino acid is made up of:




c.   Amino acids are connected by peptide bonds
producing dipeptides, tripeptides and polypeptides
http://student.ccbcmd.edu/~gkaiser/biotutorials/proteins/peptide.html
   d.    Enzymes – normal body temperature and
   pressure are both far too low for chemical reactions
   to occur rapidly enough
      *Regulators (catalysts)
      *Enzymes are specific to a molecule =
      Substrate http://www.lewport.wnyric.org/jwanamaker/animatio
                  ns/Enzyme%20activity.html

4.    Nucleic acids –
large organic
molecules made up
of C,H,O,P
 a.    DNA – Double
 helix – nitrogenous
 bases, pentose
 (deoxyribose) and
 phosphate
     b.     RNA – single strand, one nitrogenous base
     is different from DNA, pentose is ribose
5.   ATP – Adenosine Triphosphate , short term
energy molecule = Adenine + Sugar + Phosphate

				
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posted:10/14/2011
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