Should I put a "technician" pseudo-internship on my resume for biology grad school?
Yes, why not? For a grad school application, you might as well list anything that shows your interest   and involvement in your field. List it as whatever your job title was, and if possible add a line or two describing your activities.

But if possible you will want to inform them about it in more depth. If the application includes a cover letter, statement of purpose, or similar essay, use it to describe what you did in this internship and what you learned. If the application requires recommendation letters, consider asking the professor who supervised your internship to write one.