Please correct me if I'm wrong about any of the assumptions I'm operating with as I form these questions! For context, I grew up protestant, first in Church of Christ and later Assemblies of God, with lots of visits to "non-denominational" churches (if there is such a thing) and a couple one-off Lutheran/ Orthodox services.

It's my understanding that in the Catholic tradition, communion is a) blessed by a religious leader, b) administered by that leader, and c) divinely transformed so that the bread and wine become actual flesh and blood respectively.

Assuming I have that correct, I want to know what exactly causes the transformation? Is there a particular aspect of that ritual whose purpose is to invoke that change? Or does it require the combination of all of them to transform? For example, if the consuming clergy member feeds themselves, does it still work? What if the bread and wine is blessed by a believer who is not an ordained leader? If that's allowable, can that believer be a woman or do they have to be male? (Perhaps this question will lead me down a rabbit hole of what "to bless" means in various branches of Christianity, but so be it!)

In my protestant experience, grape juice was used in place of wine during communion. Is this an acceptable substitute in Catholicism? Or would that prevent transubstantiation? Does the same concept apply to bread substitutes? Does the bread have to be baked with a certain recipe? Is there a specified winemaking process or a list of Vatican-approved vineyards? I guess what really I'm asking in this paragraph is about the quantity, timing, and depth of the blessing(s)? Are the bread and wine blessed multiple times? If so, who are the different people doing the blessings? If only once, when does it happen? Right before consumption? Is it always blessed by the administrator or are the clergymen doing the blessing and doing the administrating different people?

Is there a particular passage that Catholics use to ensure they are performing the communion ritual correctly?

These questions are probably more irreverent but if answers exist, I would like to know. Which part of the body of Christ is the bread transformed into? Muscle like other meat we eat? "Flesh" as in skin? Something else? A combination? Why aren't Catholics concerned about any biohazards related to consuming the blood of another person?

My final questions are more theological. The main one being, why does Catholic tradition believe in transubstantiation? Is it because texts say that Jesus said "this is my body/ blood" or for another reason? If so, do Catholic believers hold the possibility that these things were said symbolically? In metaphor? I was raised to understand communion as a purely symbolic act, something we do to hold our focus and meditate in remembrance, but not as an actual consumption of flesh and blood.

I recognize that a lot of my questions are getting caught up in minutia, but in comparing my protestant experience to Catholicism, I've noticed that the Catholic tradition is more particular about their rituals. I'm wondering how deep those particularities run, and how those details are linked to your theology.