mc.theandromedastrein-第40章
按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！
itten on green paper：
MASS SPECTROMETRY DATA OUTPUT PRINT
PERCENTAGE OUTPUT SAMPLE 1 … BLACK OBJECT UNIDENTIFIED ORIGIN
＇Diagram of chemistry of the rock from H to Br＇
ALL HEAVIER METALS SHOW ZERO CONTENT
SAMPLE 2 … GREEN OBJECT UNIDENTIFIED ORIGIN
＇Diagram of chemistry of green object＇
ALL HEAVIER METALS SHOW ZERO CONTENT
END PRINT
END PROGRAM
…STOP…
What all this meant was simple enough。 The black rock contained hydrogen； carbon； and oxygen； with significant amounts of sulfur； silicon； and selenium； and with trace quantities of several other elements。
The green spot； on the other hand； contained hydrogen； carbon； nitrogen； and oxygen。 Nothing else at all。 The two men found it peculiar that the rock and the green spot should be so similar in chemical makeup。 And it was peculiar that the green spot should contain nitrogen； while the rock contained none at all。
The conclusion was obvious： the 〃black rock〃 was not rock at all； but some kind of material similar to earthly organic life。 It was something akin to plastic。
And the green spot； presumably alive； was posed of elements in roughly the same proportion as earth life On earth； these same four elements hydrogen； carbon； nitrogen； and oxygen accounted for 99 per cent of all the elements in life organisms。
The men were encouraged by these results； which suggested similarity between the green spot and life on earth。 Their hopes were； however； short…lived as they turned to the amino…acid analysis：
AMINO ACID ANALYSIS
＇graphic of amino acid analysis all zeroes＇
TOTAL AMINO ACID CONTENT
00。00 00。00
END PRINT
END PROGRAM
… STOP …
〃Damn；〃 Leavitt said； staring at the printed sheet。 〃Will you look at that。〃
〃No amino acids；〃 Burton said。 〃No proteins。〃
〃Life without proteins；〃 Leavitt said。 He shook his head； it seemed as if his worst fears were realized。
On earth； organisms had evolved by learning to carry out biochemical reactions in a small space； with the help of protein enzymes。 Biochemists were now learning to duplicate these reactions； but only by isolating a single reaction from all others。
Living cells were different。 There； within a small area； reactions were carried out that provided energy； growth； and movement。 There was no separation； and man could not duplicate this any more than a man could prepare a plete dinner from appetizers to dessert by mixing together the ingredients for everything into a single large dish； cooking it； and hoping to separate the apple pie from the cheese dip later on。
Cells could keep the hundreds of separate reactions straight； using enzymes。 Each enzyme was like a single worker in a kitchen； doing just one thing。 Thus a baker could not make a steak； any more than a steak griller could use his equipment to prepare appetizers。
But enzymes had a further use。 They made possible chemical reactions that otherwise would not occur。 A biochemist could duplicate the reactions by using great heat； or great pressure； or strong acids。 But the human body； or the individual cell； could not tolerate such extremes of environment。 Enzymes； the matchmakers of life； helped chemical reactions to go forward at body temperature and atmospheric pressure。
Enzymes were essential to life on earth。 But if another form of life had learned to do without them； it must have evolved in a wholly different way。
Therefore； they were dealing with an entirely alien organism。
And this in turn meant that analysis and neutralization would take much； much longer。
***
In the room marked MORPHOLOGY； Jeremy Stone removed the small plastic capsule in which the green fleck had been imbedded。 He set the now…hard capsule into a vise； fixing it firmly； and then took a dental drill to it； shaving away the plastic until he exposed bare green material。
This was a delicate process； requiring many minutes of concentrated work。 At the end of that time； he had shaved the plastic in such a way that he had a pyramid of plastic； with the green fleck at the peak of the pyramid。
He unscrewed the vise and lifted the plastic out。 He took it to the microtome； a knife with a revolving blade that cut very thin slices of plastic and imbedded green tissue。 These slices were round； they fell from the plastic block into a dish of water。 The thickness of the slice could be measured by looking the light as it reflected off the slices if the light was faint silver； the slice was too thick。 If； on the other hand； it was a rainbow of colors； then it was the right thickness； just a few molecules in depth。
That was how thick they wanted a slice of tissue to be for the electron microscope。
When Stone had a suitable piece of tissue； he lifted it carefully with forceps and set it onto a small round copper grid。 This in turn was inserted into a metal button。 Finally； the button was set into the electron microscope； and the microscope sealed shut。
The electron microscope used by Wildfire was the BVJ model JJ…42。 It was a high…intensity model with an image resolution attachment。 In principle； the electron microscope was simple enough： it worked exactly like a light microscope； but instead of focusing light rays； it focused an electron beam。 Light is focused by lenses of curved glass。 Electrons are focused by magnetic fields。
In many respects； the EM was not a great deal different from television； and in fact； the image was displayed on a television screen； a coated surface that glowed when electrons struck it。 The great advantage of the electron microscope was that it could magnify objects far more than the light microscope。 The reason for this had to do with quantum mechanics and the waveform theory of radiation。 The best simple explanation had e from the electron microscopist Sidney Polton； also a racing enthusiast。
〃Assume；〃 Polton said； 〃that you have a road； with a sharp corner。 Now assume that you have two automobiles； a sports car and a large truck。 When the truck tries to go around the corner； it slips off the road； but the sports car manages it easily。 Why？ The sports car is lighter； and smaller； and faster； it is better suited to tight； sharp curves。 On large； gentle curves； the automobiles will perform equally well； but on sharp curves； the sports car will do better。
〃In the same way； an electron microscope will 'hold the road' better than a light microscope。 All objects are made of corners； and edges。 The electron wavelength is smaller than the quantum of light。 It cuts the corners closer； follows the road better； and outlines it more precisely。 With a light microscope like a truck you can follow only a large road。 In microscopic terms this means only a large object； with large edges and gentle curves： cells； and nuclei。 But an electron microscope can follow all the minor routes； the byroads； and can outline very small structures within the cell mitochondria； ribosomes； membranes； reticula。〃
In actual practice there were several drawbacks to the electron microscope； which counterbalanced its great powers of magnification。 For one thing； because it used electrons instead of light； the inside of the microscope had to be a vacuum。 This meant it was impossible to examine living creatures。
But the most serious drawback had to do with the sections of specimen。 These were extremely thin； making it difficult to get a good three…dimensional concept of the object under study。
Again； Polton had a simple analogy。 〃Let us say you cut an automobile in half down the middle。 In that case； you could guess the plete； 'whole' structure。 But if you cut a very thin slice from the automobile； and if you cut it on a strange angle； it could be more difficult。 In your slice； you might have only a bit of bumper； and rubber tire； and glass。 From such a slice； it would be hard to guess the shape and function of the full structure。〃
Stone was aware of all the drawbacks as he fitted the metal button into the EM； sealed it shut； and started the
