The proper name is then
-D-glucopyranosyl(12) -D-
fructofuranoside.

Sucrose is common sugar.

Maltose is a disaccharide of two D-
glucose units joined by an a 14 linkage.

Cellobiose is a disaccharide of two D-
glucose units joined by a 14 linkage.

Note that the second glucose unit is drawn
upside down in order that the bond from C-4 to
the bridging O has an appropriate angle.

Lactose is a disaccharide of galactose and
glucose joined by a 14 linkage.

Lactose is the sugar found in milk. Lactose
intolerance is associated with the absence of
the enzyme which hydrolyzes the 14 linkage
to give galactose and glucose.

Starch is a mixture of amylose and
amylopectin which are polysaccharides of D-
glucose joined by 14 and 16 linkages.

Cellulose is a polysaccharide of D-glucose
joined by 14 linkages.

Animals do not have enzymes to hydrolyze
the 14 linkage between glucose units in
cellulose such that cellulose is not a digestable
food source for man.

Begin a discussion of lipids.

Lipids are one of the four major classes of
biological molecules.

Lipids are a heterogeneous group of
compounds which share the common property of
being insoluble in water but soluble in organic
solvents such as ethers, CCl4, CHCl3, etc..

Fig 11.1 describes the major types of lipids
including fatty acids, steroids, lipid vitamins
and terpenes.

We will consider the structure of fatty
acids and three lipids which contain fatty acids-
triacylglycerols, glycerophospholipids and
sphingolipids.

The structures of some common fatty acids
are shown in Table 11.1.

Fatty acids are long chain carboxylic acids.

Most fatty acids contain an even number of
carbon atoms because they are derived from
two carbon units.

Some fatty acids contain one or more
double bonds (unsaturated). In the IUPAC
nomenclature the position(s) of the double
bond(s) is indicated by the number of the first
carbon atom as a superscript to the symbol .

The naturally occurring configuration of the
double bond is almost exclusively cis as shown
for oleate and linolenate in Fig 11.3.

As shown in Table 11.1 the melting points
of saturated fatty acids increase as the number
of carbon atoms increases due to increased van
der Waals interactions between molecules.