Page 141 - The Miracle of Hormones

Communication Within The Cell

signed to sense only one single message. This is a very special instance of
design and because of this, a message cannot be sent in error to another
cell.
The great harmony in which hormones and antennae are created in
relation to one another can be compared to the lock-and-key relation ob-
served in almost all biological activity. Only the right key can open the
lock; that is, only the right cell will have anything to do with the message
sent, this message being without meaning for other cells.
At the moment the hormone reaches the cell, it sets an incredible
system into motion. By means of a very special communications system,
the message coming to the cell is sent to that cell's DNA. The cell is then
moved in action according to the message.
In order to understand just how wonderful this operation is, think
about an ordinary occurrence that everyone can encounter in their daily

life. Information is sent via the Internet to a personal computer connect-
ed to a network of other computers. The information sent to the comput-
er is transmitted to another unit, for example, to a printer, and the printer

Mechanism of Tyrosine Kinase Receptors

antenna (tyrosine
kinase)

On the membraane of
each cell are antennae that
ensure that messages are
Plasma membrane
received. These antennae
are "tyrosine kinase."
Tyrosine kinase is com-
Tyrosine posed of an antenna, a
kinase body and a tail. The ex-
domain posed part of the antenna
looks like a dish used to
receive satellite broad-
Terminal casts.
segment
(tail)

139