Translation ends when
a. the codon is missing.
b. trna detaches from mrna.
c. a stop codon is reached.
d. mrna leaves the nucleus.

Translation

Remember that transcription happens in the nucleus as it changes from DNA to mRNA.  In translation,
    the mRNA first has to leave the nucleus and go into the cytoplasm of the cell.  The process of translation actually occurs in the cell’s ribosomes.

The process of translation uses the genetic code on the mRNA strand to direct the construction (making) of a protein molecule.
1.  A ribosome attaches to an mRNA molecule in the cytoplasm.
2.  As each codon passes through the ribosome, tRNA molecules bring the matching amino acids into the ribosome.  Each tRNA has a set of 3 unpaired nitrogenous bases called an anticodon which matches up with the codon coming through the ribosome.  So one end of a tRNA has an anticodon and the other end carries the amino acid which is how the code is translated.
3.  The ribosome and the rRNA molecules it contains attach the amino acids together as they are being translated.  The protein chain will keep growing until the ribosome reaches the stop codon on the mRNA.  At that point, translation is done and the ribosome lets go.

Hope this helps!!! 

when it is at an intermediate population density