Page 90 - The Miracle in the Cell

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Figure 4.3
Proteins are built
according to DNA
Cell instructions. In the
membrane nucleus, synthesized
RNA receives from the
DNA the relevant
6 instructions needed for
2 protein synthesis. It
takes these instructions
to the ribosomes and
7 carries out protein syn-
3
thesis on these
organelles. Proteins
ER
synthesized on ribo-
somes found on the
surface of the endo-
Rough plasmic reticulum are
ER deposited at the endo-
plasmic reticulum for
4 transport.

1-EXOCYTIC VESICLES
The budding vesicles of the Golgi 5-ENDOCYTIC VESICLES
body carry the substances they contain Forming as buds on the cell membrane,
towards the cell membrane. The sub- they import substances from outside the
stances that the cell doesn't want or for cell. When they arrive at the lysosomes,
which the body has no need are ejected digestive enzymes break them down,
from the cell. along with their contents.
2-GOLGI BODY
6-LYSOSOMES
Transported proteins and lipids are Containing digestive enzymes, they pro-
stored here, and classed according to duce basic raw materials the cell needs
their duties. Substances are then stored by digesting macromolecules arriving
in cell organelles as needed.
from outside the cell. The vesicle that
enters the cell transports substances to
3-TRANSPORT VESICLES
the lysosomes.
Vesicles deliver proteins and lipids to
the Golgi body, where they will be 7-MICROBODIES
stored. Just like lysosomes, they contain diges-
tive enzymes that break down sub-
4-ENDOPLASMIC RETICULUM (ER) stances such as fats and hydrogen
peroxide.
Many proteins are produced by ribo-
somes found on the surface of the
rough ER. Lipids, on the other hand,
are synthesized on smooth ER. Both
substances are either secreted out of
the cell or stored.

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