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Chapter 4 Notes
Carbon and the
Molecular Diversity of
Life
Concept 4.1
Compounds containing carbon are said to
be organic compounds.
Carbon atoms are very versatile.
- have 4 valence electrons. It will share
electrons in 4 covalent bonds
(tetravalence)
Concept 4.2
Variation in carbon skeletons contribute
to the diversity of organic molecules.
- long chains form carbon skeletons
- often bonded to several hydrogen
atoms forming a hydrocarbon.
Concept 4.2
Concept 4.2
Isomers: compounds that have the
same molecular formula, but different
structures (with different properties).
- structural: differ in the covalent
arrangements of atoms.
- geometric: same covalent properties,
but differ in spatial arrangements.
- enantiomers: mirror images
Concept 4.2
Concept 4.3
Functional groups: components of
molecules that are often involved in
chemical reactions.
- ex. difference between testosterone
and estrogen.
Concept 4.3
Estradiol
Testosterone
Concept 4.3
6 functional groups are commonly found.
- hydroxyl, carbonyl, carboxyl, amino,
sulfhydryl, and phosphate.
- all are hydrophilic and increase the
solubility of organic compounds in
water.
Concept 4.3
Hydroxyl group (-OH)
names usually end with suffix –ol
ex. ethanol
organic compounds w/ OH are
alcohols
note: do not confuse w/ OH-
Concept 4.3
Carbonyl group (-C=O)
-carbon double bonded to an oxygen
atom.
- if at the end of the carbon skeleton
will be an aldehyde (ex. propanol)
- if in the middle of a carbon skeleton
will be a ketone (ex. acetone)
Concept 4.3
Carboxyl group (-COOH)
- oxygen is double bonded to a carbon
that is also bonded to a hydroxyl group
- compounds are called carboxylic
acids (ex. acetic acid)
- has acidic properties w/ the loss of H+
ions
Concept 4.3
Carboxyl
STRUCTURE
Carboxylic acids, or
organic acids
Has acidic properties
because the covalent bond
between oxygen and
hydrogen is so polar; for
example,
EXAMPLE
Acetic acid, which gives
vinegar its sour taste
Acetic acid Acetate ion
Found in cells in the ionized
form with a charge of 1– and
called a carboxylate ion
(here, specifically, the
acetate ion).
NAME OF
COMPOUND
FUNCTIONAL
PROPERTIES
Concept 4.3
Amino group (-NH2)
- a nitrogen atom is bonded to two
hydrogen atoms and a carbon skeleton
- compounds are called amines
- compounds that have both amino and
carboxyl groups are called amino acids
- ex. Glycine
- amino group can act as a base (NH3+)
Concept 4.3
Amino
STRUCTURE
NAME OF
COMPOUND
Amines
EXAMPLE
Glycine
Because it also
has a carboxyl
group, glycine is
both an amine and
a carboxylic acid;
compounds with
both groups are
called amino acids.
Acts as a base; can
pick up an H+ from
the surrounding
solution (water, in
living organisms).
FUNCTIONAL
PROPERTIES
(nonionized) (ionized)
Ionized, with a
charge of 1+, under
cellular conditions.
Concept 4.3
Sulfhydryl group (-SH)
- Sulfur is bonded to a hydrogen and a
carbon skeleton
- compounds with –SH are called
thiols
- help stabilize the structure of
proteins
Concept 4.3
Phosphate group (-OPO32-)
- formed by dissociation of phosphoric
acid (H3PO4)
- used in the transfer of energy
between organic molecules.
Concept 4.3
Phosphate
STRUCTURE
EXAMPLE
Glycerol phosphate
In addition to taking part in
many important chemical
reactions in cells, glycerol
phosphate provides the
backbone for phospholipids,
the most prevalent molecules
in cell membranes.
Organic
phosphates
NAME OF
COMPOUND
Contributes negative
charge to the molecule of
which it is a part (2– when
at the end of a molecule;
1– when located
internally in a chain of
phosphates).
FUNCTIONAL
PROPERTIES
Has the potential to
react with water,
releasing energy.