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Mt. Holz Science Fiction Society
08/02/02 -- Vol. 21, No. 5
Table of Contents
A Question with a Twist (comments by Mark R. Leeper):
I have had a question at the back of my mind for several years. It constitutes a small crisis of faith that the view of the universe as it has been presented to me is completely understood as well as people think it is. I have asked several people, all knowledgeable about science, and I have gotten different answers from each. In fact the best answer I have gotten was from a friend who knows his stuff really well, Bill Higgins, who told me straightforwardly that he simply did not know the answer. Fair enough. Certainly it is the sort of question that I expect would have a well-known answer and the answer does not seem at all well- known. The question appears to me to be perfectly straightforward and one that anyone would ask, but then my background is mathematical. There are probably very few people who look at what they have learned in the field of biology who ask themselves if something they have learned makes sense from the standpoint of mathematical topology.
Well, rather than be mysterious, let me tell you what the question is. Our genetic reproductive system is based on DNA. DNA is made up of a very long molecule in the form of a double helix. That means there are really two strands that run the length of the molecule wrapping around each other, almost as if the molecule was a very long ribbon that was twisted. It is twisted very many times. If what I have been told is correct and I remember it, it is twisted somewhere on the order of 100,000 times for human DNA. This means that each strand goes around the other strand 100,000 times. When the two strands are ready to replicate they break apart and each strand goes its merry way. This process takes on the order of thirty minutes. Then each strand basically reproduces a mate identical (but for possible mutations) to the one it just lost. And, Voila!, reproduction has taken place. I think I got that right. The textbooks and the NOVA TV programs show diagrams of this happening always showing just a short segment of the DNA with almost no twist. And everybody thinks they completely follow what has just happened. Everyone but me that is. I still have a bad feeling about that explanation. I am trying to picture what happens when you have ten twists in the section of the helix, never mind 100,000. Now the two chains are each wrapped around the other ten times. Pulling them apart is a little harder to picture. Unless the ends start spinning to unwind you just push the twists down the helix where they bunch up.
If that is not clear, try this experiment. Take two pieces of thread each the same length, about a foot long, one black, one white. Place them side-by-side and then twist them tightly together so that they make one thick string made of a black strand and a white strand. Now grab them toward the middle of the string and separate the two strands, one black, one white, for maybe a quarter of an inch. Now try to sharply pull the two threads apart. Without the ends spinning very fast the threads just will not separate. The same thing has to happen to the DNA molecule. How fast does it have to be spinning in DNA? Well if there are 100,000 twists and it has to separate in about half an hour that is 100,000/1800 revolutions per second. That works out to be about 56 revolutions per second. That is not tremendously fast as gasoline engines go, but it still is pretty fast as I picture cellular biology actions happen. It must take a log of energy. And it has to be very well organized so that we don't run into the kinking that we would get with the threads. It is pretty close to the rotational speed to a car engine. Maybe that is how thing happen, but it seems like it would require a lot of energy to do that. It makes the cell seem a lot more active than I had imagined it was.
As one friend explained to me sagely, I was looking at it wrong. These are not threads, he explained, but molecules. "They do not have to do all that spinning because they are being separated by an enzyme." "So?", I asked. "Well the enzyme does the separation." "So how do the two strands separate without all the untwisting?" "The enzyme does it." Now my respect for enzymes is second to none. They are just super little proteins in my book. That is mostly because I am not sure exactly what an enzyme can do. But there is one thing I am almost certain an enzyme cannot do. An enzyme cannot break the laws of mathematics. They are not allowed an exemption from the mathematical laws of topology. If two long chains of a molecule are twisted together no enzyme is going to get them apart unbroken by any means but untwisting them.
Not quite so much energy is required if you can break a strand where you want and rejoin it. Some people have claimed that is one function of an enzyme. That may make this less of an logistical feat, but not that much less. There still is a lot of untwisting to account for.
So I really have two questions. One is how does the separation handle all the untwisting. The other, which may sound a little pompous, I admit, but I will ask it anyway. With all the people who have studied DNA and how it works from high school biology to laboratory study, why haven't more people asked themselves this question? [-mrl]
READ MY LIPS (film review by Mark R. Leeper):
CAPSULE: French thriller about a partially deaf woman who can read lips. The skill proves to have unexpected upsides and downsides when she gets involved with a parolee who wants to use the talent. There are tense scenes but the plot is too much building up to one particular sequence and then tidying up afterward. Rating: 6 (0 to 10), +1 (-4 to +4)
READ MY LIPS is an action thriller from France that features a slow build of tension to a meager pay-off. I would feel a little better about it as a film if I felt that it was a whole film. Instead, I feel there is one really good scene. The rest builds up to that scene and then squares things up after it. Admittedly there is some suspense and some action in the build-up and the tidy-up parts, but they are all mostly in service to one scene that is fairly clever. One fairly good scene wrapped in some good suspense is more than most crime films give the audience but not quite enough to make this a standout film.
Carla Bhem (played by Emmanuelle Devos) has serious problems in her job as a secretary in a contracting firm. She is nearly deaf and totally marginalized to the point where she can barely hear and she is barely seen. Certainly her workspace is the in the low rent end of the office near the restroom and the copier. People use her desk to leave half empty paper cups and if people spill coffee on her desk in the process they usually do not even notice they have done it. She is used as one more service to the working staff. Her supervisor, however, suggests that she is over-worked and should hire help. For one of the rare times she thinks she can get a perk out of working in the office. She can choose the type of person she wants as a helper. She has very specific requirements.
The employment agency sends over a man, Paul Angeli (Vincent Cassel). Carla is glad to have someone to help and who knows she exists, but she is worried she may be training her own replacement. She quickly discovers that Paul is a prison parolee with no experience--not much of a threat. Carla decides to keep him in that narrow range, too good for the bosses to fire but not good enough to replace her. She is determined to help Paul hide his past and to help him hold his job. She savors a little odd sexual tension with Paul, but does not want to let on. She also decides she can use Paul's criminal talents to move her up an inch or so in office politics. However, when Paul discovers Carla reads lips he thinks he knows an unorthodox way to put her skill to use for him.
Paul and Carla play games of control on each other and allow a little sexual tension to bloom. That is unusual in a film in which the two main characters are not presented as being particularly attractive people. Each of them is sly but in very different ways. Toward the middle of the film things become a little more complex and a little harder to follow. Part of the problem in this part of the story is that a plot has been added with Paul's parole officer. It strikes the viewer as an add-on of little value to the main line of the plot. In fact, when it does impact the main line it ties one hole up only by opening another. In the last third of the film there is a turn for heavier violence and blood. Carla is pulled by Paul into a hard-knocks world that she is unprepared for. Some members of the audience were bothered by the graphic depiction of torture, an unusual degree for a film treated as an art film.
Though the film's style has been compared to Hitchcock, though these are not the entirely innocent people that Hitchcock usually would have used. They are game players. To emphasize any connection to Hitchcock Alexandre Desplat's score even uses violins for tension in style much like Bernard Herrmann would have for a Hitchcock film. Jacques Audiard co-wrote and directed. Perhaps the film delivers more as a character study than as a thriller, but I rate at a 6 on the 0 to 10 scale and a +1 on the - 4 to +4 scale. [-mrl]
Mark Leeper firstname.lastname@example.org Quote of the Week: Travel, instead of broadening the mind, often merely lengthens the conversation. -- Elizabeth Drew
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