—— 
THE FRUIT AND THE SEED 291 
or starch. Reserve cellulose is found in some palm seeds and 
also in the seeds of some other plants (Figs. 14, 298, 294), 
Fats and oils. The natural fats and fatty oils in plants and 
animals all belong to the same general class of compounds and 
are composed of glycerin (C,H,(OH),) combined with organic 
acids. Glycerin has three OH groups which can be replaced 
by acid radicals. In natural fats all the groups are replaced, so 
that natural fats are triglyc- 
erides. Fats are composed 
of carbon, hydrogen, and oxy- 
gen, and are characterized by 
a small percentage of oxygen, 
as may be seen from the for- 
mulas of such common fats as 
stearin (C,H,O,), palmitin 


110 
we 
(C,,H,.0,) olein (CoH. OD) uh or vas 
and linolein (C,,.H,,O,). Ow- ay TS aK x ae 
ing to the very small per- 2-49 “OD or Ss 
centage of oxygen contained i) \\ BRGrYOX 
Bee vue oxidation of fats 1, 993 Thickened walls of hemi- 
produces large amounts of cellulose from betel-nut palm seed. 
energy. More energy is ob- (x 140) 
tained by oxidizing a given 
volume of fats than by oxidizing a similar volume of any known 
kind of compound that is found in either plants or animals. 
Fats may be solid or liquid (oils), according to the temper- 
ature. Fatty oils occur in plants in the form of globules 
(Figs. 295-298). . 
Proteins. The proteins are the most important group of com- 
pounds found in plants, as they constitute the active matter 
of protoplasm, and the chemical phenomena of life processes 
are associated with them. 
Proteins are exceedingly complex compounds, as will be seen 
from formulas which have been calculated for such representative 
proteins as zein (C,,.H,.,,.N,,,0..53), from Indian corn; gladin 
foe NO. S.), from wheat; casein (C,,,H_.N,,,O.0, 4) 
1068 2 
