Untitled - Kelly Walsh High School

Organic, Biochemistry, and Polymers 315
In solution, the chain structure of glucose is in equilibrium with two different
ring forms of glucose. The two different ring structures of glucose are a-glucose
and b-glucose. These two forms differ in the position of an [OH group relative
to the carbon at the far right side of the ring.
H
C
HO
HO
OH
CH 2
C
H
C
H
H
C
O
C
OH
H
OH
H
α β
H
C
HO
HO
CH 2
C
H
H
O
C
OH
Polysaccharides formed using these two different types of glucose will have different
properties. Joining units of b-glucose, results in the formation of cellulose.
However, if we join units of a-glucose the result is starch. A minor difference in
structural linkage makes the difference between a tree and a potato.
21-7 Nucleic Acids
H
HO
H
H
CHO
C OH
C H
C OH
C OH
CH 2 OH
Nucleic acids are the molecules in our cells that direct and store information for
reproduction and cellular growth. There are two types of nucleic acids: ribonucleic
acid (RNA) and deoxyribonucleic acid (DNA). Both of these nucleic acids
are unbranched organic polymers composed of monomer units called
nucleotides. These nucleotides are composed of a sugar molecule, a nitrogen
base, and phosphoric acid. A single DNA molecule may contain several million
of these nucleotides, while the smaller RNA molecules may contain several
thousand.
OH
C
C
H
OH