Unfortunately, I didn't spend too much time
I
strongly suggest spending a little more time on this. The last thing you could want is getting reject from a backup because you didn't put enough effort into its application.
As I paused at the window, watching her gaze at a computer screen that was harvesting the energy of powerful x-rays to observe molecules at the atomic level, questions inundated my mind.
Who is here referring to? The wording here is a little awkward too. I suggest splitting the sentence up into two.
A physicist of Argonne National Laboratory was conducting a tour of the Advanced Photon Source, and s he
Maybe a typo? If it is, disregard the first question on the second note above. :]
I want to see differentiation, stoichiometry, phospholipids, Newton's laws, and other textbook concepts manifest themselves practicallyreal life .
I want to apply what I know by creating something with raw materials that is cost effective and that also unravels problems, fights diseases, and benefits others.
You don't need commas here since you're describing with the object immediately with the words "with" and "that."
One more suggestion: Try to add smoother transitions between the paragraphs. It is a bit jumpy to me.