Biomedical Engineering Reference
In-Depth Information
TABLE 3.1
Chemical Species and Their Representation
Chemical species: chemical compound, element, or living system.
Water; Nitrogen; Corn; Escherichia coli
Elemental formula: elemental chemical composition of species
H
2
O
d
water
N
2
d
nitrogen
Isomeric species (isomers): same stoichiometrical formula but different sterostructure
CH
2
OH
CH
2
OH
CH
2
OH
CHO
CHO
CHO
CHO
CHO
CHO
HCOH
HCOH
HCOH
CO
CO
CO
HOCH
HOCH
HOCH
HOCH
HOCH
HOCH
HOCH
HOCH
HOCH
HOCH
HOCH
HOCH
OH
OH
OH
HCOH
HCOH
HCOH
HCOH
HCOH
HCOH
HCOH
HCOH
HCOH
HO
HO
HO
HCOH
HCOH
HCOH
HCOH
HCOH
HCOH
HCOH
HCOH
HCOH
OH
OH
OH
OH
OH
OH
HO
HO
HO
CH
2
OH
CH
2
OH
CH
2
OH
CH
2
OH
CH
2
OH
CH
2
OH
CH
2
OH
CH
2
OH
CH
2
OH
OH
OH
OH
(inositol)
(inositol)
(inositol)
(Glucose)
(Glucose)
(Glucose)
(Mannose)
(Mannose)
(Mannose)
(Fructose)
(Fructose)
(Fructose)
all share the same stoichiometrical formula C
6
H
12
O
6
Roel's formula: stoichiometrical formula normalized based on carbon
Sugar:
CH
2
O
Xylan H(C
5
H
8
O
4
)
200
OH:
CH
1.602
O
0.801
a disaccharide composed of one glucose residue and one fructose residue. Plants form
these molecules as food reserves for themselves; we harvest the plants and extract sucrose
from them in water solution. We have also bred strains of cane and beets that produce
much more sucrose than wild strains.
Sucrose is rapidly dissociated into glucose and fructose by the enzymes in your
mouth and in your stomach, and your taste receptors sense sweetness. In aqueous
solution, fructose presents in two different isomers:
D
-fructopyranose (70%) and
D
-fructofuranose (30%). The more desired isomer is
D
-fructofuranose; it tastes five
times as sweet as glucose and
D
-fructopyranose. Both sugars have the same calories,
and the soft drink companies want
to advertise lower calories for an acceptable
sweetness.
Chemical engineers figured out how to run the reaction to convert glucose into fructose
glucose
#
fructose
(3.1)
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