Are questions that deal with reverse-engineering/understanding biological phenomena on topic ?
I personally won't mind seeing any question about understanding "how things work", be it software, hardware, or a natural process. However, I suspect there won't be many biologists here so I don't know if you'll get any useful answers. Doesn't mean you can't try! Maybe there will be some insights that we can offer.
One example that just came to mind is the saying: "reverse engineering is like solving a crossword puzzle". First you get the easy and obvious words, then look at the intersections and try to guess the others. The more you uncover, the more you know about the yet unknown. I can see this being applied to almost anything that you need to understand.
Given the intended audience of the site, the scope extends to any field of engineering. It is not limited to computer-related topics, whatever the example questions on Area 51 might suggest (experience on Area 51 shows that the example questions rarely capture the topic of a site precisely and are best ignored once the beta starts).
However, biology is more about natural phenomena than about engineering. Reverse engineering applied to natural phenomena is called science. That's not what this site is about. Questions about understanding biological phenomena are best posted on Biology Stack Exchange.
That being said, if you have a biology question that you think is related to reverse engineering, please ask it. Such things are best debated based on examples, not in the abstract.
I think that if you were reverse engineering a biological system and you the asker were an expert in biology but not reverse engineering it would be perfectly on topic.
If you come here asking how DNA works or how do I use a printer to print amino acids and inject those in a cell... and such. Then you should be on a biology SE and not here. It would be akin to asking a question about how to use a text editor or IDE here.
I think such question probably will need a great deal of context but if a person is an expert in the field of thier reverse engineering then they should be able to provide that. In any case DNA computers are real and based in classical computing unlike quantum computers. In the end the question should probably be devided into RE and Biology related parts.