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tes
a, Every cell must receiis a complete heredity. Any structural
defect of a cell roszits in faulty function.

be ivery cell must recive food, water, and free oxygen. “ith
Chemical bodies broustht to it by the blood, it:

= indi \- its om structure and supplies its fuactional
oe mat:cr‘al.

ce. Every tissue cell mut be relieved »f its wasse products.

ds. Every tissue cell uet be functionally aciiv..

e. Every tissue cell must have periodic rust.

Specialized Cell Function

 

Cells have specialized furctions in tie body. aa underst-ndine of this
is essential to a proper grasp of the laws of heredity and the appli-
cations of the principies of hygiene. Somatic or souy cell. are ti
specialized cells of various types that compose all of the organs and
structures of the body. A small grour, called germ cells, are set aside
in the early stages of developrent for the single purpose of reproducing
the next generation,

Cell Division

Cell division is the biological process going on within the cells upon
whieh depends reproduction, the transmission of heredity, the development
of organs, the growth of structures, and all of the possibilities of
differentiated function,

The steps by woich these units of life produce the individual can best
be understood sy a study of the two principal processes of cell division,

a. Mitosis or indirect division of nucleus.

Phases: a, Prophase c. Anaphase
b. Metaphase d. Telophase

b. Meiosis is the term applied to the process by which the chromos‘:zc
nivinsr in the germ cells is reduced by half, or from diploid ‘v

haploid °

Phases: Reduction division
Equation division

These two divisicns res.it in

(1) Four sperms, or male gametes, all capab!e uf participating in
fertilization

(2) zour ova, only one capable of fertilization. The other three ova
thus formed are immature cell.» and are discarded by the body.

Meiusis is vie physiological organiz2tion for the proéuction of
differert assortments of hereditary faetors in the chromosomes of
the germ ceils.