Biology Molecule essays

Biology Molecule essays -man is high 50s to 60% water -distribution in body divided into 3 compartments: 2) intercellular/interstitial fluid - 11 litres - 80% -waters properties result from its structure and molecular interactions -polar covalent bonds and asymmetrical shape give it opposite charges on -electrons spend more time around O giving H a slight positive charge -hydrogen bonds form between the oxygen of one molecule and the -cohesion: substance being held together by hydrogen bonds -hydrogen bonds are transient yet enough is always held together to give water more structure than almost any other liquid -beads and meniscus formed by cohesion (also helps upward transport of -adhesion counteracts downward pull of gravity -water has greater surface tension than most liquids -surface molecules are hydrogen bonded to molecules below and around -surface tension can hinder life (i.e. beading in the alveoli of lungs) -makes water unwettable -surfactants used to counteract this -water has a high specific heat which allows it to resist extreme temperature -has a high heat of vaporization that causes it to require alot of energy to -when sweating, heat energy is utilized to change states from liquid to gas, -as a solid water is less dense than as a liquid and will float -charged regions of molecules have an electrical attraction to charged ions -water surrounds ions separating and shielding them from one another -polar compounds are generally soluble -charged regions of water are attracted to oppositely charged regions of -polar molecules are miscible in other polar liquids -most water molecules dont dissociate (~ 1/554 million do) -hydrogen atom in hydrogen bond between the two water molecules may shift from the oxygen atom it is covalently bonded to the unshared orbitals of the oxygen that it is hydrogen bonded to -hydrogen ion is transferred creating a hydronium io...

Reagan and the 1983 Marines Barracks Massacre in Beirut

Reagan and the 1983 Marines Barracks Massacre in Beirut In 2002, the Presidential Oral History Program at the University of Virginia’s Miller Center of Public Affairs interviewed Caspar Weinberger about the six years (1981-1987) he spent as Ronald Reagan’s Secretary of Defense. Stephen Knott, the interviewer, asked him about the bombing of the U.S. Marines barracks in Beirut on Oct. 23, 1983, which killed 241 Marines. Here’s his answer: Weinberger: Well, that’s one of my saddest memories. I was not persuasive enough to persuade the President that the Marines were there on an impossible mission. They were very lightly armed. They were not permitted to take the high ground in front of them or the flanks on either side. They had no mission except to sit at the airport, which is just like sitting in a bull’s eye. Theoretically, their presence was supposed to support the idea of disengagement and ultimate peace. I said, â€Å"They’re in a position of extraordinary danger. They have no mission. They have no capability of carrying out a mission, and they’re terribly vulnerable.† It didn’t take any gift of prophecy or anything to see how vulnerable they were. When that horrible tragedy came, why, as I say, I took it very personally and still feel responsible in not having been persuasive enough to overcome the arguments that â€Å"Marines don’t cut and run,† and â€Å"We can’t leave because we’re there,† and all of that. I begged the President at least to pull them back and put them back on their transports as a more defensible position. That ultimately, of course, was done after the tragedy. Knott also asked Weinberger about â€Å"the impact that the tragedy had on President Reagan.† Weinberger: Well, it was very, very marked, there was no question about it. And it couldn’t have come at a worse time. We were planning that very weekend for the actions in Grenada to overcome the anarchy that was down there and the potential seizure of American students, and all the memories of the Iranian hostages. We had planned that for Monday morning, and this terrible event occurred on Saturday night. Yes, it had a very deep effect. We talked a few minutes ago about the strategic defense. One of the other things that had a tremendous effect on him was the necessity of playing these war games and rehearsing, in which we went over the role of the President. The standard scenario was that â€Å"the Soviets had launched a missile. You have eighteen minutes, Mr. President. What are we going to do?† He said, â€Å"Almost any target we attack will have huge collateral damage.† Collateral damage is the polite way of phrasing the number of innocent women and children who are killed because you’re engaging in a war, and it was up in the hundreds of thousands. That is one of the things, I think, that convinced him that we not only had to have a strategic defense, but we should offer to share it. That was another of the things that was quite unusual about our acquiring strategic defense, and which now seems largely forgotten. When we got it, we said he would share it with the world, so as to render all of these weapons useless. He insisted on that kind of proposal. And as it turned out, with this cold war ending and all, it didn’t become necessary. One thing that disappointed him most was the reaction of the academic and the so-called defense expert community to this proposal. They were horrified. They threw up their hands. It was worse than talking about evil empire. Here you were undermining the years and years of academic discipline that you shouldn’t have any defense. He said he simply did not want to trust the future of the world to philosophic assumptions. And all the evidence was that the Soviets were preparing for a nuclear war. They had these huge underground cities and underground communications. They were setting up environments in which they could live for a long time and keep their command and control communications capabilities. But people didn’t want to believe that and therefore didn’t believe it. Read the full interview at the Miller Center for Public Affairs.