What is the relationship between dna rna and protein synthesis?

The process of proteins synthesis starts with DNA which contains the information that is going to be used to create the proteins. A molecule called RNA polymerase uses one of the two DNA strands as a template to create an mRNA molecule which contains the base pairs that complement the DNA strand. If the cell is a eukaryotic cell then the mRNA molecule needs to leave the nucleus and then attach to a ribosome. If the cell is prokaryotic then the ribosome binds without the mRNA molecule having to be moved locations (in fact the mRNA doesnt even have to be complete for a ribosome to begin its process). So the ribosome attaches to the mRNA and as each codon (group of three base pairs) moves into each of the three spots in the ribosome, it gets read, then a tRNA molecule brings and matches a protein subunit which gets attached to the chain of protein subunits that are being created and then the codon exits the ribosome. The ribosome knows to attach because of a "start codon" that is usually AUG and knows to stop adding to the protein chain when it reaches a "stop codon".