Page 141 - Engineering in Nature

Harun Yahya

Micro-tubules fulfill a great many
functions inside the cell, most of
which can be performed only when
the micro-tubules are separated. Yet
as is the case with the hairs, micro-tu-
bules connected together are neces-
sary for some other tasks. Therefore,
how do specific proteins join to-
gether when necessary?
If micro-tubules had the charac-
teristic of joining themselves to-
gether, like the tubulin, they would
constantly do so and thus, be unable
to perform many of their functions
within the cell. Therefore special con-
nectors between the micro-tubules
have been created, such as the pro-
tein nexin, which connects the end of
one micro-tubule, consisting of two
conjoined links, to another.
Furthermore, on every micro-tu-
The top picture shows the micro-
bule are also two separate protru-
tubes in full. Below, how the move-
sions made up of the protein dynein, ment of the dynein and nexin
known as the outer and inner arms. proteins turns into a bending
movement, during which the dy-
Dynein is different to nexin. Its task
nein and nexin assume different
is to work like a kind of engine and functions. While the dynein acts
create a mechanical driving force in- like an engine, the nexin helps to
keep the structure together. If the
side the cell. For that reason, nexin
nexin and dynein lacked these
complementary properties, the tiny
hairs would be unable to move.

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