I've never been a bacteria (thought women have called me a parasite at times) but I imagine they don't have experience. Experience/consciousness is a magical thing that happens with the help of a brain. It's the picture you're looking at right now, and the sound of sounds you hear.
Your second question is really about convention, since you're asking about what a word means. You can say consciousness is a requirement, but I think the way the concept of "life" is usually understood, awareness of experience is not a requirement. If it was, you would end up saying that a dog does not qualify as being alive (possessing life) and that sounds strange.
The question is really how to treat a creature that is at a certain age, not how to define it. It's kinda funny, actually, that people need to categorize things into a protectable class before saying it has rights and values.
But, the 'certain age' criteria will have to fall back into a particular categorization of age, no? And justification of why. And, thus, what is the beginning - when does age 0 start? And, if categorized as age 0, does that inherently assume it to be 'alive' from then on? We can't help but fall prey to the traps & limits of categorization.
Intriquing question and I won't attempt to answer it from an INFP perspective. But I have a comment.
I heard this week on the radio that a physician performing an abortion had delivered a living embryo and had disposed of it in the trash where it was discovered much to people's outrage.
There is so much irony in this announcement that I don't know where to begin. The news labled it a "living baby."
I thought, "When are we going to make up our minds?"
"No ray of sunshine is ever lost, but the green which it awakes into existence needs time to sprout, and it is not always granted to the sower to see the harvest. All work that is worth anything is done in faith." - Albert Schweitzer