4. A major difference between synthetic biology and genetic engineering is that synthetic biology involves the creation of new DNA sequences and biological systems, whereas genetic engineering is limited to working with existing ones. Thus, genetic engineering is more about biology, since the focus is on studying the way biological systems work in nature by isolating and observing them in different situations. The engineering is then just a means to study biology. On the other hand, although synthetic biology also can involve existing systems as well as new ones, its focus is on manipulating those systems to improve them or use them for some other functions other than their intended ones in nature. Thus, biology provides the foundation and tools, but engineering is ultimate goal. For instance, a genetic engineer might isolate the gene encoding GFP in jellyfish and express it in e.coli in order to study how it is produced in a simpler and better understood organism. At the same time, a synthetic biologist might use the GFP sequence as a reporter in e.coli by placing it downstream from an inducible promoter. While both use molecular biology to manipulate GFP in their experiments, they each have very different purposes in mind. Because synthetic biology is more about engineering, it attempts to simplify and describe biological systems so that they may be easier to manipulate or reproduce. As with many engineering disciplines, synthetic biology starts with "problems", such as how to make genetic sequences into interchangeable parts. The synthetic biologist will often look to other engineering designs outside of biology in order to solve these problems.