I'm reading between the lines a little here, but I suspect that what you really want to ask is whether or not a person is generally taken seriously as a researcher without formal graduate training.
The answer is likely not. Certainly there are exceptions. There are may M.D.s for example, who publish research on a regular basis. But in general, the formal education is what gives you the background in a field to know what problems need to be researched. It also gives you the experience to know what information to include in a paper and when to make reference to other work. This is, of course, on top of giving you the tools to conduct any research properly and effectively.
It is unconventional for a person to write a paper, and give it to a professor simply for feedback without that professor having been a part of the research in one way or another.
What you will run into is not so much a case of respect or lack thereof. Without proper credentials, people will naturally scrutinize your work to a much higher degree because there is no mechanism in place that assures them that your methods have at least at some point been subject to review.