How does the study of bacteria cells help us understand how protein synthesis works in the human cells?

Because bacteria often use very similar biochemical pathways to those used in human cells to manufacture amino acids and proteins. Bacteria are much easier to grow than human cells are, and since they are much less complex it is easier to work out how the the biochemical processes work. Once it is figured out in bacteria, human cells can be tested to see if they use the same,or similar pathways.