Page 82 - The Miracle of Protein

80 THE MIRACLE OF PROTEIN

The Copied Information Reaches

the Production Center
Once the necessary information for protein synthesis has
been found and copied from the DNA inside the cell nucleus,
that copied information must now reach the factory, the ribo-

somes, where the protein will be produced. Ribosomes are out-
side the nucleus, in the fluid-filled area called cytoplasm. These
organelles called ribosomes are present in every cell. They are
located at a comparatively long distance from the DNA and dis-

tributed throughout all the cytoplasm. The production orders
must be rushed to these factories in a flawless manner. Messen-
ger RNA (mRNA) heads straight for the ribosome without los-
ing its way among the many organelles and molecules in the cell.
When it finds the ribosome, the mRNA settles in a line on its
outer surface. In this way, information regarding the amino acid
sequences of the protein to be manufactured, reaches the pro-

duction center in the correct form. The mRNA, in addition to
the data of the protein to be produced, also carries information
about what it must do both to start and finish the gene. There-
fore, when these instructions reach the ribosome, messages be-

gin to be sent to other regions of the cell to bring the amino
acids, in other words the raw materials necessary for the pro-
20
tein's manufacture to the ribosome. Special molecules called
tRNAs (transfer RNA) carry out this transportation task.

Translation of the Messenger RNA
Data and raw material required for the protein to be syn-

thesized are now ready. The production order has been trans-
mitted to all the machines along the production line, but anoth-
er problem now needs to be resolved. The production data is