Page 162 - The Miracle of Hormones

Centrioles

Smooth endoplasmic
reticulum
Ribosomes
Plasma membrane
Smooth
endoplasmic
reticulum

Mitochondrion

Nuclear pore
Lysosome

Golgi complex
Rough endoplasmic
reticulum

Nucleolus
Nuclear envelope
Nucleus
The structure of the cell

oxygen to the blood, stimulating the cells to action and adjusting the
level of sugar in the body.
What we want to concentrate on here is the flow of protein traffic
that happens when newly produced proteins change their place in the
cell. Because some of these proteins begin to be used immediately within
the cell, they must be carried to the place where they are to be used; oth-
ers are sent to a protein storage area of the cell for later usage. Proteins
that will be used outside are removed from the cell under the supervision
of the cell membrane. In the meantime, proteins that enter the cell from

outside, again under the supervision of the membrane, form an impor-
tant part of this dense protein traffic. In short, within the tiny parameters
of a cell there is an incredible amount of activity. Even rush hour traffic in
a large city where millions of people live is really at a standstill compared
to the dynamism in a cell. Moreover, this dense activity is carried on by
our proteins that are about one millionth of a millimeter in size, that
inhabit our cells that are one hundredth of a millimeter in size. It is
extraordinary that billions of tiny units of matter fit into a space too small

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