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This is about science produced by the California Institute of Technology and originally broadcast by station KPCC in Pasadena California. The programs are made available to the station by national educational radio. This program is about the nature of life with host Dr. Peter listen and his guest Dr. Robert sense I'm er professor of biology here now is Dr. Leslie Mann. What is life. What is the meaning of the question anyhow. For some for the philosophy it is official to say that to ask is to live well a man has lost his philosophers and his artists. What is life how is it written. What is the Book of Life. How is it in coded. How does it start and how to conclude. One of man's artists the playwright Oscar Wilde remarked in his play that the Book of Life begins with a man and a woman in a garden and ends with revelations.
Well we don't want to go so far into that supremum but rather telling cynicism man the social animal half in fear and half in hope looks to the sky these days possibly for an answer to life seeking an end to his loneliness in this vast deep and mysterious universe. What will he find out their life and will he find life as we know it. Or will we encounter some alien and extremely different form of life. How do we know what life means anyhow. When confronted with a blob of chemicals what tools. What knowledge can we use to tell ourselves which side of the threshold of life that blob of chemicals is on is that a rock. Or is it a plant. Well this question concerning the status of the living and non-living and distinguishing between them has bothered mankind for some time and even our complex detailed study of biology the science of life hasn't given us the concise satisfying answer that we really need. We could go back to Aristotle
who said that the animate is distinguished from the inanimate by living there what does that mean. It's not bad for Aristotle but it seems a little shallow to us now especially since biologists are moving closer and closer to the goal. The biologist is one of our best sources for understanding life and his advances in technique tools and ideas in the past few decades have put us on the threshold of understanding. Part of the great mystery. Our guest is Dr. Robert sometimes professor by physics and biology at Cal Tech who participated very recently with two Stanford University colleagues in the synthesis of a living fully active virus. Doctor since Haim are a member of the National Academy of Sciences the American Academy of Arts and Sciences is a native of Washington D.C. He took his bachelor's master's and Ph.D. degrees at MIT and has been teaching at Celtic since
1957. Prior to that he was Professor of Biophysics at I was state college. Now Bob I'd like to start off by asking you what are some of the money questions that man has asked about life. Well as you mentioned this is a question that has perplexed philosophers and other people or other thinking people for literally millenia. They have tried to understand what it was about life that distinguished it from the living and indeed the early ideas were clearly a very simple mind you have the old myths about the statue was brought to life by a spark from the gods and so on. When one when this question was considered in
more detail with the kind of knowledge that was available at that time I think one can say that the general ideas that were put forth were of two kinds. The one was of the sort of mention that the living was distinguished from the living by some special spark some vital spark which was intrinsically different so that living matter simply was basically different from non-living matter. It wasn't the same thing it was made up out of the same element. That's right it was that composed of the same kinds of materials. Do we feel that way now Bob. No we certainly don't. We know very well that the atoms that compose living matter are just the same as the kinds of atoms you find outside living matter. So we integrate step removed that basic mysticism. Yes. The other. Approached the other cons conception of life was that life was due to a
special organization of matter and this idea well it had some proponents which had to Big make convincing because you no one knew what this organization was and so you couldn't make a convincing case for what kind of an organization could give rise to the various phenomena that we associate with life. However I imagine that our knowledge of living organisms now has has really removed a lot of the uncertainty about as I do this book. Oh very much so in the last few decades particularly what has happened really has been that as one learn more and more as one penetrated into the mysteries if you will of life and of the unit of life itself that the need to postulate some special any kind of special forces or special kinds of matter has just decreased to more and more until now it's really vanished and
we feel we can explain. In our line at least the events going on you know living system in physical chemical terms so we can really explain much of the life process and as you say we think of the cell as the building block the prototype of all life. But what really is a cell in simple terms. If such things so can be described I think is the unit of life it is the minimal structure which is of sufficient complexity and is sufficiently organized that it can maintain itself and reproduce itself in a relatively simple external medium. It has and as one has to understand what a cell has to do when can appreciate that an organism much simpler or smaller than that simply wouldn't be able to do these things.
So a cell has to satisfy certain minimal requirements to be a member of a club of cells Issaquah. Absolutely and that I think is why one finds a minimal size to cells. If it were smaller than that it just couldn't have enough organization enough components to do these various front carry out these various functions. It just couldn't be smart enough and have enough pockets to do all the multitude of things that are required to live live even at that very very simple level right. What are the minimal requirements above. Well as we see them now. And of course in a way this comes down to a kind of definition of life. We would say that as far as we can conceive anything that was living would have an X Tierno boundary would have what we would call a membrane usually. Which preserve the organization inside both from the
effects of agents that might come at it from the outside in just from the natural tendency to diffuse so you couldn't get the various specialized chemicals and components that are made inside of a living cell could freely diffuse out it could never accumulate enough to carry out its functions. So it has to have a sort of skin. But human terms that's right. Secondly of course there is nothing that we know of in life that. Enables it to overcome or get around any of the natural laws of physics life proceeds in accordance with the natural laws and therefore it has to proceed in accordance with the known laws of thermodynamics and this means it uses energy and therefore any organism that is living has to have some means to tap an external source of energy. In Generally this is either light
that is photosynthesis or chemical energy in that which is present in certain compounds that they can find the cell confined in by you know the way that it has to eat or has to eat to plug into some power source from somewhere. The third element that we find in our kind of life is the presence of specific catalysts that is Moloch large molecules which direct the reactions that go on in cells so that these reactions proceed at usable rates from the one he in. More importantly in the particular directions that are desirable for the cell and the there's a lot of precision required in order to maintain a living organism in this precision is produced by the presence of these specific catalysts that direct reactions in particular ways.
Another component or region which we would regard as a requirement probably for any living organism is what we might call an information and control center. That is the living organism receives from its ancestors and passes on to its descendants a set of hereditary instructions for making the various components of the cell and these over the long course of evolution these can be changed gradually and so the new combinations can be tried out. But over the short course from each cell to then each generation of the next generation. These must be very precisely transmitted with minimal change if you had errors creeping into the system in such a complex system it would soon just disintegrate but would it be too much to
consider that a source of intelligence in the cell. Maybe information is a better word that used intelligence has so many human cavitation is it that we prefer. Probably the use the word intelligence. They request to go along with this erratic carry information you have to have the means of translating it to reading it and making use of it. In each generation and indeed this imposes the continuity of life whereas in principle it or read it carry information that is passed on can be used to direct the synthesis of devices to read itself there have to be some devices to read it in the first place. But I'd like to interject at this point to ask you something about your experimental techniques how we know how do we know all
this detailed information about cells that you've just given us well. Part of the reason for the advances that have been possible in biology in the last few decades has been the development of a variety of very sophisticated and powerful techniques I could mention for example the electron microscope is one which has enabled us to literally visualize many of the fine components of cells in living organisms. We can really see them really at these huge magnification huge major patients down not to the quite to the atomic level but to the molecular level. Another tool of immense importance has been the use of radioactive isotopes which is enabled us to label compounds and follow their fate as they go through the various metabolic processes in the cell or
organism. The other centrifuge a tool which enables us to play a very high gravitational forces has been of great value in studying the large molecules found in cells. This is a way Bob by which you can apply these forces and break the molecules up so that you can break them or more importantly or they used to separate molecules of different sizes and to determine their sizes. I guess the another tool of the physicists X-ray diffraction is a very useful tool Yes this is enabling us to really determine in your favor bookcases the actual molecular structures of these large molecules found in cells which we cannot yet at least see in the electron microscope. But we can determine this by X-ray diffraction. So many of these things you've spoken about in fact all of them represent
experimental tools brought over in a sense from the physicists. What about theoretical advances Bob. There have been. Perhaps a few theoretical advances one of but the theoretical variance I would consider a generalization would include one of the most interesting and useful generalisations which has come out of recent work is the uniform universality of life. The uniformity of life that all the cells of all the different kinds of life on earth are built on pretty much the same principle. They all use the same hereditary code for example. They are made of the same kinds of biochemical molecules so that things that we learn in one organism can be carried over to many other organisms. In other words even the lowest form of life contains the same little pieces that we have made up. That's right that's right.
So you say that that is really a rediscovery way. This was something that had been questioned previously. Well of course it in a sense it's inherent in the general idea of evolution which as you know was postulated by Darwin and really very strongly supported by the evidence that he accumulated which was largely of a morphological kind. Now we have it on a deeper molecular level we have a very clear biochemical evidence for evolution. The most satisfactory explanation of this uniformity and universality of the biochemistry of life is that all life has evolved from one common basic form. How about computers do you use them much. In some kinds of work particularly in the work where you accumulate large amounts of data which has to be sorted out the two
fields in particular one of the already mentioned X-ray diffraction where tens of thousands of diffraction spots have to be analyzed and correlated. The other field where in great use is being made of computers in the study of the nervous system where one is attempting to analyze and make sense out of the patterns of nerve impulses on many neurons in the act. But what about the style of your experimental work. Is this conducted on a fost scope or are we still in the classic tradition of the scientist in the work that you do. It's perhaps a little mixed. I would say it is. The work is still largely done by one or two scientists working with their students and a few technicians. In that sense I think it is classic it. On the other hand the expense involved equipment particularly computer time things of this have changed by orders of magnitude of what could
be done although I imagine there still orders of magnitude below that of the high energy physicists. Oh yes we don't have any tools that cost hundreds of millions of them and so it's still possible for a man working by himself with a few intimate friends to make really major advances in this field without too large expenditures of money. That's really true and it's a very fortunate thing. It's a wonderful thing I should think that as much as any of the other fascination of this field would make it one of the most attractive today. But we've talked about cells and how we know these things about them. But let me ask you the next question how do the cells themselves know what to do. That's a good question that there were a couple of more Elop components in in cells that I didn't quite mention before. I had one very important element in all living cells is what one might term
regulating self regulating mechanisms. These are quite analogous to the negative feedback systems of the engineer whereby the amount of a component that is made is regulated automatically within the cell by essentially just chemical feedback mechanisms. This is the sort of thing that stops a cell from just growing and growing and growing and so is your good size now stop. Well that's a more dynamic process. This depends on whether you're talking about a free cell or a cell in a multi say organism. A free living cell when it reaches a certain size will in general divide reproduce. Of course this is important property in a higher organism they have to be control mechanisms that tell cells that just tell the whole organ such as your liver. You've grown enough and stop and then if that organ is injured it can repair and then stop.
And of course all this is related to DNA. Intrinsically Yes because every time a cell divides your DNA and that seems to be the level at which to control it basically went to some of the other ramifications of the DNA and RNA of course a stock woods these days I suppose most of us use them without fully understanding what they are. But what are some of the other ways in which they affect the self. Well provide first of all of the inherited information. Secondly they provide the point at which controls are observed. There's another point I'd like to make and that is obviously this information is of the greatest importance to the SO and therefore it is essential that it be preserved intact both throughout the life of the sale and passed on to the next generation. And for this purpose rather ingenious repair mechanisms have been developed which take
advantage of the fact the information is really present twice and which can recognize. You might say with the normal kind of information from a damaged and better furry since you have a present twice ordinarily only one of these would be damaged and then they can recognise this and by referring to the undamaged. Type a bit and damaged my copy repaired the damaged target where there is a must a set of records kept there that is it does the right its just that I double my that's And it is only double and it always there always just to name a very fascinating aspect. I mean it's a very important aspect but one of the arguments that people made against the idea that life could be due to organization. Why is it such a complex organization would inevitably be subject to random disasters and fall apart you know I think this idea of
a self repairing system apparently never occurred to the people who made this kind of objection. Yes that of course is a very interesting and subtle aspect of intelligence in a sense. What about the self destructive aspects of some of these cells such as the virus and its behavior. Well of course life. Fortunately or unfortunately long ago learned to live another life in the viruses. So in a sense a specialized form of this which is the disease adapted to make use of the machinery inside a cell and modify that machinery in and directed in such a way as to make more virus instead of more self. And as you say that can be quite destructive to the cell but it's an interesting point the
virus must not be too variable. If a virus killed off all its hosts it would kill itself. Oh yes it must that nothing set some sort of crock control yet where exactly. Well what about some of the positive things that we might be able to do by then how to control DNA. Since DNA is the genetic material by learning how to control DNA we should be in the position of information which would enable us to control many kinds of viral disease which would enable us ultimately to correct hereditary defects which are responsible for many kinds of human elements and in the long run to begin to modify our own inheritance. That's possibly the most fascinating aspect of all what. What do you mean by it. If you consider man as we do as sort of the current end
product of two billion years of evolution. Man is clearly becoming the dominant species but man it is not so far beyond the species which preceded him. I mean man's only been on earth for a limited number millions of years over compared to two billion years and the number of genetic changes between man and his predecessors is not that great. So man is by no means a finished work of God. By now I would think it would be very strange if he were and so we don't see any reason to believe for example that man's intelligence is the highest form of intelligence that could be developed. And that in principle it should be possible by further genetic changes to develop some of it. For example intellectual properties to stages considerably beyond what they are present but mimic a typical example. We very well know that people differ in their memory capacity.
There really are people who have photographic memory now maybe it would or wouldn't be a good thing that everybody did. But at least the possibility for providing that could be developed in principle. I'm not saying we know how to do it this time and I think it is a biologist. It's hard to imagine that evolution is going to stop with me and yet because competition has been wiped out as far as man's concerned future evolution is going to have to be a conscious product of Man's Desiring to do it. So in concluding Bob you really do think that men will be able to change man in the future. Yes I really do. So there we have. Something of a view of our approaches towards the mystery of life we've seen that living matter a baize nature's basic laws and we've seen that similar and again in how different
all the types of life can be. It's amazing to me that the same basic processes sustain creatures as low as the sea urchin and as fancy as man. And amazing too that man is so viable in his ability to change he isn't barren meant always to adapt and adjust and yet he still retains the similarity to the creatures. Yet at the same time man looks for even more flexibility. And we've talked today about some of the most evocative and exciting thoughts of what the biologists and bio geneticists may be bringing to us the possibility of altering the genetic makeup of man himself to produce men who are disease resistance who A Better Man who think better maybe who played better who act better simply a more perfect world inhabited by more perfect human beings I don't want to use the word Superman but that of course also raises a serious question.
Who's to decide what sort of super individuals we have and will they be the right question and one can't help thinking here of the great occasion when Ellen Terry that beautiful Victorian actress suggested presumably jocularly to George Bernard Shaw the brilliant playwright and social thinker that they produce a baby. I think she said of an individual with your brains and my looks back Madam replied. Sure. Consider a man with my looks and your brain. So what sort of world will we live in and how can we cope with this. We'll leave that question open. Thank you Bob. Thank you. This was about science with host Dr. Peter less a man and his guest Dr. Robert sense of humor join us again for our next program. When Dr. lesser men will lead another discussion on a scientific subject about science is produced by the California Institute of Technology and is originally
broadcast by station KPCC in Pasadena California. The programs are made available to the station by national educational radio.
About science
About the nature of life
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California Institute of Technology
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University of Maryland (College Park, Maryland)
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This program focuses on a scientific view of the nature of life. The guest for this program is Dr. Robert Sinsheimer.
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Interview series on variety of science-related subjects, produced by the California Institute of Technology. Features three Cal Tech faculty members: Dr. Peter Lissaman, Dr. Albert R. Hibbs, and Dr. Robert Meghreblian.
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Guest: Sinsheimer, Robert
Host: Hibbs, Albert R.
Producing Organization: California Institute of Technology
Producing Organization: KPPC
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University of Maryland
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Duration: 00:28:13
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