Learning Center
Plans & pricing Sign in
Sign Out



  • pg 1
									   Water as a solvent
     Acids, bases and pH

   Organic compounds
     Hydrocarbons
     Functional groups
     Dehydration synthesis/
                 Water and life
4. The universal solvent
  • Water can form hydrogen bonds with any polar or
    ionic compound.
  • Therefore, many things can be dissolved in water
        The dissolving agent is called the solvent
        The dissolved substance is called the solute
        A liquid of two or more evenly mixed substances is a
                  Acids & Bases

   Acids:
       Donate H+ ions to a

   Bases
       Accept H+ ions &
        remove them from
            So what is pH??
   pH= A measure of hydrogen ion concentration, but
    on a logarithmic scale.

   Solutions with high hydrogen ion concentrations
      have low pH

      are acidic

   Solutions with low hydrogen ion concentrations
      have a high pH

      are basic

   There is a 10-fold difference in hydrogen ion
    concentration between solutions that differ by one
    pH unit.
Some common acids, bases and
 Neither acids or bases
 Can form when acids and bases react
       The dissociated hydrogen ions and hydroxide
        ions join to form water.

       The remaining ions form ionic bonds creating a

       This is an example of neutralization.
         H+Cl- + Na+OH- →             Na+Cl- + H+OH-
         Hydrocloric + Sodium          Sodium + Water
         acid         hydroxide       chloride
Implications of acid precipitation
      in the environment…
   Molecules containing carbon and hydrogen

   Long chains or rings of carbon form
    backbone of diverse biological compounds.

   All organic molecules have a carbon skeleton.

    ◦ This determines the overall shape of the molecule.

   Organic molecules differ in these ways:

    1. The length and arrangement of the carbon

    2. Which atoms are attached to the skeleton
Length of the skeleton: Dehydration
     Synthesis and Hydrolysis
   Dehydration synthesis:
    Monomers are linked
    w/covalent bonds to form
    polymers; water is released.

   Hydrolysis:
    Polymers are later
    dismantled into monomers
    by organisms during
    digestion; water is added.
       Arrangement of the skeleton:

   Organic molecules can have
    the same number and
    composition of atoms, but
    can have different

   These are called isomers.
       • Molecules with the same
         empirical formula but different
         structural formulas.
Atoms attached to C-H skeleton
   Macromolecules are very large organic

   The most important organic compounds found in
    living things are:

        1.   Carbohydrates
        2.   Proteins
        3.   Nucleic acids
        4.   Lipids
   Compounds with a 1:2:1 ratio of C:H:O

   Monomers are monosaccharides; polymers are
      Source of energy
      Provide structural support
   Simple sugars are
    described by the
    number of carbons in
    the molecule.
    ◦ Triose-3 carbons
    ◦ Pentose-5 carbons
    ◦ Hexose-6 carbons

   Examples of simple
    ◦ Glucose (C6)
    ◦ Fructose (C6)
    ◦ Galactose (C6)
Di/poly-saccharide formation
   When two or more simple sugars are
    combined they form complex

    ◦ Formed via dehydration synthesis

   Disaccharides

    ◦ Two simple sugars (ex. Lactose or sucrose)
   Contain many simple sugars

   Examples of polysaccharides:

    ◦ Starch and glycogen
      Used for energy storage

    ◦ Cellulose
      Important component of plant cell walls.
   Monomer is an amino
    acid; polymers are
    ◦ Functions in structure,
      energy, enzymes

   An amino acid contains:
    1. Amino group
    2. Carboxyl group
    3. Side chain **

   There are 20 different
    amino acids
   Amino acids are joined via dehydration
    ◦ The bond formed between amino acids is called a
      peptide bond.

   Several amino acids joined together form
    polypeptide chains or proteins.
   The sequence of amino acids in a polypeptide
    constitutes the primary structure of the protein
   Polypeptides twist and fold into their secondary
    ◦ Form a-helix or b- sheet
   The various a-helices and b-sheets interact
    to form a globular structure.
 Multiple polypeptide chains interact to form
functional protein
   The protein’s overall shape determines function

    ◦ Example: Sickle cell anemia

    ◦ A mutation in one gene causes the protein to
      have a different shape- changes RBC shape.

    ◦ Different shape altered function
  When heat or other environmental conditions break
  the bonds that stabilize tertiary structure.
   Structural – main component of bone,
    muscle, cartilage
   Movement – skeletal muscle
   Immunity- antibodies
   Enzymes –catalyze chemical reactions
   Hormones – insulin
   Oxygen transport - hemoglobin
   Monomer is a nucleotide:
    ◦ 5-carbon sugar
    ◦ phosphate group
    ◦ nitrogenous group

   Polymer is DNA or RNA
    ◦ Deoxyribonucleic acid
      (DNA)- sugar is
    ◦ Ribonucleic acid (RNA)-
      sugar is ribose
        1. Replicate itself
2. Store information and pass to   3. Make proteins
   Each DNA molecule is made of two strands.

    ◦ Strands are made through dehydration
      synthesis of many nucleotides

    ◦ Strands are held together by hydrogen bonds
      between the nitrogenous bases. The bases pair
      according to base pair rules
      Adenine - Thymine
      Cytosine – Guanine

   The two DNA strands are twisted on each
    other, forming a double helix.
   Each DNA strand is divided into segments called
    ◦ Genes are the recipes for proteins.
       The sequence of nucleotides in a gene
        dictate the order of amino acids in a

   Each DNA strand is called a chromosome

   Human cells have 46 chromosomes in each cell.
    ◦ Each cell copies all of these chromosomes
      before it divides to pass along to daughter
   RNA is a single stranded molecule

   Nucleotides:
    ◦ Contains uracil instead of thymine

   Base pairs with itself and DNA
    ◦ A-U
    ◦ G-C

   RNA is found in three different forms:
        mRNA (messenger RNA)
        rRNA (ribosomal RNA)
        tRNA (transfer RNA)
 Adenosine triphosphate (ATP):
the nucleic acid that stores energy
   Composed of C, H and a little O, but no fixed
    ◦ Non-polar (do not dissolve in water)

   There are three types of lipids:
             True fats (e.g. pork chop fat and oils)
             Phospholipids (membrane components)
             Steroids (most hormones)

   Functions:
    ◦   energy source
    ◦   Structure
    ◦   insulation
    ◦   vitamins, hormone precursor
   Used to provide

   The building blocks of
    fats= fatty acid

    ◦ A glycerol molecule
    ◦ Three fatty acid tails.
   If the carbon skeleton of a fatty acid has as
    much hydrogen as possible, the fat is called a
    saturated fat.

   If the carbons of a fatty acid have double
    bonded carbon molecules in them, the fat is
    called unsaturated fat.
     Trans (Elaidic acid)                     Cis (Oleic acid)                               Saturated (Stearic acid)

                                                                            Stearic acid is a saturated fatty
Elaidic acid is the principal trans   Oleic acid is a cis unsaturated fatty acid found in animal fats and is the
unsaturated fatty acid often found    acid that comprises 55–80% of         intended product in full
in partially hydrogenated             olive oil.[23]                        hydrogenation. Stearic acid is
vegetable oils.[22]                                                         neither cis nor trans because it
                                                                            has no double bonds.

                                                                                        This fatty acid contains no double
These fatty acids are geometric isomers (structurally identical except
                                                                                        bond and is not isomeric with the
for the arrangement of the double bond).

                                                          ^ Alonso L, Fontecha J, Lozada L, Fraga MJ, Juárez M (1999). "Fatty acid composition of
                                                          caprine milk: major, branched-chain, and trans fatty acids". Journal of Dairy Science 82 (5): 878–
                                                          84. doi:10.3168/jds.S0022-0302(99)75306-3. PMID 10342226.
                                                          ^ Alfred Thomas (2002). "Fats and Fatty Oils". Ullmann's Encyclopedia of Industrial Chemistry.
                                                          Weinheim: Wiley-VCH. doi:10.1002/14356007.a10_173.
   Phospholipids:
    ◦ Are complex organic
      molecules that resemble
      fats but contain phosphate

   Phospholipids are the
    major components of cell
    ◦ Some are known as
   Nonpolar molecules that are arranged in rings of carbon

   Steroids are important components of cell membranes.
    ◦ Cholesterol

   Steroids often serve as hormones and serve in
    regulation of body processes.
    ◦ Testosterone, estrogen
             Cholesterol: LDL vs HDL
Cholesterol does not travel freely in the bloodstream. Carried by lipoproteins (L)

               LDL                                         HDL

LOW Density Lipoproteins                    HIGH Density Lipoproteins

Deposit excess cholesterol                   Remove cholesterol from
    on arterial walls.                            the blood.

      “bad” cholesterol                          “good” cholesterol

To top