Now we'll follow the messenger RNA copy back out of the nucleus to see how a new protein is made.
On the left is the endoplasmic reticulum, which we've seen before,
and on the right is a new structure called the Golgi apparatus, which we'll visit again later.
Straight ahead are more of the glowing mitochondria.
In the cytoplasm, the messenger RNA is released from its carrier proteins and binds to a complex called a ribosome.
Here, the ribosome, a huge molecule, is shown as a multicolored structure.
The ribosome reads the information encoded in the RNA and assembles a protein from amino acids found in the cell.
Many ribosomes can operate at the same time to make multiple copies of the protein.
The ribosomes anchor on the outer membrane of the endoplasmic reticulum.
If you look carefully, you can see the ghostly shapes of the newly made proteins accumulating on the inner side of the membrane.
Once the job is done the ribosomes and RNA part company.
The newly made proteins leave the endoplasmic reticulum wrapped in a layer of membrane called a vesicle.
They travel toward the Golgi apparatus, on the right, where the proteins are modified and sorted for transport.
The loops of the Golgi are busy with protein traffic moving in and out.
The vesicle fuses with the membrane at one end of the Golgi and a new vesicle, containing the modified proteins, is pinched off the other side.
The new vesicle transports the proteins through the cytoplasm, delivering the proteins to where they are needed.
Some proteins are used inside the cell.
Others, like these growth factors, must be exported.
Here, the vesicle fuses with the cell membrane, dumping the proteins outside the cell.
The released growth factors will communicate with other cells to continue the healing process.
These growth factors will attract more fibroblasts to the wound site and remodel the clot for better healing.
Other proteins produced by this signaling pathway will tell the fibroblast cell to grow and divide, making many new cells to heal the wound.
With the cooperation of many different cells, damage to the injured knee can be quickly repaired.
Every day, your cells communicate and cooperate to keep you healthy.
They act and interact; they grow, divide and die; all through the amazing language of cell signals.