For me, the answer to those questions is yes, and yes. In vitro fertilization deals with actual "clumps of cells," and if someone raped my daughter, I'd not only want the abortion to happen, but I'd be happy to kill the rapist. Personally.
Oh, EDIT - but also, abortion is always the killing of a human. Sperm is human, the egg is human, the blastocyst is human, etc. These are all stages of human development. That is one factor in the analysis, but not the only one. The mother, too, is human.
One way I look at it is that abortion is hardly ever "desirable." But, sometimes it is necessary or the best course of action out of only bad options. Sometimes, life doesn't give you a "good" option. So, I'm with ya on the in vitro, and the rape issue, but I also have no trouble acknowledging that the embryo or fetus is human. It is. There isn't any getting around that. So, when one is in favor of abortion, it is definitely killing a living thing that is human - a stage of human development. And, sometimes, that's what needs to happen. But that doesn't mean that all times are equal - certainly, there are differences, and someone who gets an abortion because she just doesn't feel like taking care of a baby is one thing, and someone who gets an abortion because she's traumatized by a rape is quite another. That's just my view on it.