2. 17.1 biological functions of lipids
• As an energy source, lipids provide 9 kcal of
energy per gram
• Triglycerides provide energy storage in
adipocytes
• Phosphoglycerides, sphiggolipids and steriods
are structural components of cell membranes
3. HOW TO CLASSIFY LIPIDS
• By solubility
• And molecular weight
• And the functional groups
• “biological structure vs Molecular properties”
• Was our main theme
4. “biological structure vs Molecular
properties
• It also enables classification of such
compounds as gangliosides as lipids, although
they are more soluble in water than in organic
solvents.
5. Eicosanoids and star lipids!!
• Examples of biologically important fatty acids
are the eicosanoids, derived primarily from
arachidonic acid and eicosapentaenoic acid,
that include prostaglandins, leukotrienes, and
thromboxanes.
6. • They usually contain even numbers of carbon
atoms in straight chains (commonly C14 to C24),
and may be saturated or unsaturated; they
can also contain other substituent groups.
7. CLASSIFY AMINES NOW
• Amines
• Amines are derivatives of ammonia in which
one or more hydrogen atoms are replaced by
alkyl groups. We indicate the degree of
substitution by labeling the amine as either
primary (RNH2), secondary (R2NH), or tertiary
(R3N). The common names of these
compounds are derived from the names of the
alkyl groups.
8. common names
• Amines
• Amines are derivatives of ammonia in which
one or more hydrogen atoms are replaced by
alkyl groups. We indicate the degree of
substitution by labeling the amine as either
primary (RNH2), secondary (R2NH), or tertiary
(R3N). The common names of these
compounds are derived from the names of the
alkyl groups.
10. systematic names
• The systematic names of primary amines are
derived from the name of the parent alkane
by adding the prefix -amino and a number
specifying the carbon that carries the -NH2
group.
12. amines mirrors the chemistry of
ammonia
• The chemistry of amines mirrors the chemistry
of ammonia. Amines are weak bases that pick
up a proton to form ammonium salts.
Trimethylamine, for example, reacts with acid
to form the trimethylammonium ion.
13. IMPORTANT CONCEPT
• These salts are more soluble in water than the
corresponding amines, and this reaction can
be used to dissolve otherwise insoluble
amines in aqueous solution.
14. Amides
It is tempting to assume that carboxylic acids
will react with amines to form the class of
compounds known as amides. In practice, when
aqueous solutions of carboxylic acids and
amines are mixed all we get is an acid-base
reaction.
15. aqueous solutions of carboxylic acids
and amines are mixed all we get is an
acid-base reaction.
16. • The best way to prepare an amide is to react
the appropriate acyl chloride with an amine.
17. • Excess amine is used to drive the reaction to
completion by absorbing the HCl given off in
this reaction
