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David Gergen, editor at large of U.S. News & World Report, engages Boyce Rensberger, science writer for the Washington Post, author of Life Itself: Exploring the Realm of the Living Cell.

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JIM LEHRER: Now a Gergen dialogue. David Gergen, editor at large of "U.S. News & World Report," engages Boyce Rensberger, science writer for the "Washington Post," author of "Life Itself: Exploring the Realm of the Living Cell."

DAVID GERGEN: Boyce, you’ve been covering science for over 30 years, and in your book you seem absolutely fascinated by what’s going on in cell research. What brings this passion out in you now?

BOYCE RENSBERGER, Author, "Life Itself": Well, to me, it’s just the most fascinating thing there is. If you stop and think about what we as human beings are, we are some kind of machine in--this miraculous machine, marvelous machine. What is it that’s inside us, that makes us able to do such a simple thing as move, or a more complex thing like to think? And I just can’t think of anything more fascinating than to know how that works.

DAVID GERGEN: What have we learned now? Crick and Lotts when they won their Nobel Prize for the double helix in DNA, that was about 30 years ago, 35 years ago, what have we learned in the last 20 or 30 years?

BOYCE RENSBERGER: Oh, my God, we’ve learned most of what we know about cell--how life works has been learned since then. I mean, what they showed was the double helix structure of DNA. What was learned subsequently was what does that double helix structure do? You know, what do the pieces of that, of the chromosome do? We learned much more about what the cell does with that information? You know, there’s more to life than just DNA. We hear all these stories about finding the gene for this or for that, but there’s--a gene literally does not do anything, except just sit inside the nucleus of the cell and let the rest of the cell’s machinery read its message and act on it. And all the work is done by other things. And what we’ve learned is a lot of that other stuff.

DAVID GERGEN: About the cells, themselves.

BOYCE RENSBERGER: About what the cell does. I mean, a gene is to a cell as the software on a disk is to everything that a computer can do. It just sits there. You need all the rest of that hardware to make the--to make the software do anything useful.

DAVID GERGEN: Right.

BOYCE RENSBERGER: And we need all the rest of the cell to make the gene useful.

DAVID GERGEN: Right. Let’s talk about the cells, themselves. You said in the human body there are about 60 trillion cells.

BOYCE RENSBERGER: Sixty trillion. That’s 60 million million cells.

DAVID GERGEN: Right.

BOYCE RENSBERGER: That’s a lot.

DAVID GERGEN: Now, I’ve always assumed they are quite small, but you said there are some cells which are actually very large.

BOYCE RENSBERGER: There are some cells that are large. The largest one in terms of length--those are the cells that are the nerve cells that run from the base of your spinal column out to the farthest point from that, which in most people is the tip of the big toe, so that’s a distance of several feet.

DAVID GERGEN: That’s one single cell.

BOYCE RENSBERGER: One single cell stretches that whole length. There are many more cells running parallel to it, and bundled up, they make a nerve.

DAVID GERGEN: Fascinating. Now, the ordinary cell, how many can fit--we used to talk in the Middle Ages about how many angels can dance on the head of a pin.

BOYCE RENSBERGER: They’re bigger than angels. Well, I don’t know about the head of a pin, but if you look at say the dot on an "i" in a piece of newspaper or book type, about 200 cells can be fitted side by side on that circular dot.

DAVID GERGEN: Now, what’s really interesting about your book was how much was going on inside that little, little tiny cell.

BOYCE RENSBERGER: It’s incredibly tiny. Most of them are not that long. They’re much smaller. And we used to say that what was inside a cell was protoplasm, and today that’s an extinct term. There is no such thing as protoplasm unless you mean that’s everything that’s in there. Now that we’re able to look very closely at going inside the cell and see what’s there, we see it is--every cell is jam-packed with machinery, with molecules that are doing jobs, that are moving around. There’s a transportation system inside cells with network attracts, with containerized cargo that’s hauled around on those tracks by little molecular motors. You know, your genes tell certain machinery in the cell to make a protein of a certain kind. They do that. The protein may belong in some other part of the cell, or it may be that it’s supposed to go to a different part of the body entirely. It gets containerized and hauled off to those places. All this stuff is going on simultaneously. If you get down and look at it, it’s just a chattering factory-like environment.

DAVID GERGEN: Four or five centuries ago, as you write, people thought that the soul actually made things move within the cells, made the body move, sort of these vital forces in the body. What really makes it move?

BOYCE RENSBERGER: What really makes it move is a type of molecule that--you call them molecular motors, motor molecules, that can actually swivel. When they get with a certain other kind of molecule--a phosphate binds to them. This is the way energy is carried around inside the body. When they get a little piece of that to them, they flex. And our cells like muscle cells are built so that they have lots of these motor molecules in long parallel strands. And one reaches out and grabs the other and pulls on it. When you want your muscles to work, that’s what happens.

DAVID GERGEN: Right.

BOYCE RENSBERGER: Millions of times. And it pulls, and it’s just like pulling on a rope hand over hand.

DAVID GERGEN: What is magical to me is that it all works. It’s so complex, the complexity.

BOYCE RENSBERGER: It is incredibly complex. And yet, the more you know about it, the more wonderful it seems, just the more astonishing.

DAVID GERGEN: Does this new research bring facts to light that are important for the abortion debate about the formation of life, itself, the moment of conception, for example, as part of the abortion debate?

BOYCE RENSBERGER: I think it does. I think it does. And I’ve never understood why this hasn’t come out more in the debate. For example, there is no such thing as the moment of conception, unless you make an arbitrary definition for it. Between the time the sperm meets the egg, it’s another--after that time, it’s another two weeks before you have the first cell that is going to be part of the baby. Up until that time, the--that fertilized egg cell is constructing a rudimentary placenta. It’s got to find a way into the lining of the woman’s uterus, implant into that uterine wall, tap into the mother’s bloodstream, and once that kind of life support system is established, then it can start developing this specialized structure that will become the baby. The rest of it is the placenta.

DAVID GERGEN: So rather than having a single moment of conception, it’s a gradual process?

BOYCE RENSBERGER: It’s a gradual process of many, many steps.

DAVID GERGEN: When does the fetus become a person, in your judgment?

BOYCE RENSBERGER: Well, I don’t--I don’t know when it becomes a person, any precise moment, but it’s clear to me that it’s--again, it’s a gradual process of many steps. For example, is there a person if there is no functioning brain? We tend at the end of life to say, no, there isn’t. Well, the fetus doesn’t have a functioning brain until around the beginning of the third trimester. You have at about 25 weeks of gestation is the first time the nerve cells in the cortex of the brain--that’s the part that does our thinking--that’s the conscious part that--the part of the brain that’s special about humans--that’s the first time those cells make connections with each other, form synapses, as they’re called. So there is no communication among cells until about 25 weeks. Then it’s another five weeks before the cells of the cortex have synapses with the rest of the brain and are connected to the rest of the body. So there’s 30 weeks before the brain has any communication or information from the outside womb, before it can feel anything.

DAVID GERGEN: I know we’re on dangerous territory, but in reading your book, I had the sense that the research suggested or strengthened the argument of the pro-choice folks for perhaps the first two trimesters, but the research for the last trimester strengthened the life of the pro-life people for the last trimester.

BOYCE RENSBERGER: I can see how that, you could take that position, because at about 35 weeks you--if you do EEG studies, brain wave studies, on the fetus, which you can do through the mother’s abdomen, you find the brain waves begin to resemble the pattern that you would see in a newborn infant. And you could take that to mean it’s got the brain that’s got the kind of electrical activity that’s communicating within itself the way a newborn would. And from the brain point of view, maybe it is more like a newborn.

DAVID GERGEN: Do you think we’ll ultimately be able to explain life itself?

BOYCE RENSBERGER: Well, it depends on how much you--how satisfying you want to be--how satisfied you’d like to be from the explanation. There’s always--almost every discovery raises new questions, well, how does that work, okay, what makes that happen, and what makes that happen? And there’s a kind of endless regression, that there’s so much more we know now that we did just twenty or thirty years ago, that it’s pretty wonderful; it’s pretty amazing to me. I’m fascinated by it.

DAVID GERGEN: Boyce Rensberger, we’ll look forward to your next book. In the meantime, thank you very much.

BOYCE RENSBERGER: Thank you very much. I appreciate it.

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