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在很多NN心经中,都强调了框架、架构、结构、套路的重要性,为什么很少有人讨论关于结构、套路的的话题呢? 今天,在总结此文套路结构的时候,又看不清楚了,希望大家指点、讨论~~ Passage 14
Nearly a century ago, biologists found that if they
separated an invertebrate animal embryo into two parts
at an early stage of its life, it would survive and develop
as two normal embryos. This led them to believe that the
(5)cells in the early embryo are undetermined in the sense
that each cell has the potential to develop in a variety of
different ways. Later biologists found that the situation
was not so simple. It matters in which plane the embryo
is cut. If it is cut in a plane different from the one used
(10)by the early investigators, it will not form two whole
embryos.
A debate arose over what exactly was happening.
Which embryo cells are determined, just when do they-
become irreversibly committed to their fates, and what
(15) are the “morphogenetic determinants” that tell a cell
what to become? But the debate could not be resolved
because no one was able to ask the crucial questions
in a form in which they could be pursued productively.
Recent discoveries in molecular biology, however, have
(20) opened up prospects for a resolution of the debate.
Now investigators think they know at least some of the
molecules that act as morphogenetic determinants in
early development. They have been able o show that,
in a sense, cell determination begins even before an egg
(25) is fertilized.
Studying sea urchins, biologist Paul Gross found
that an unfertilized egg contains substances that func-
tion as morphogenetic determinants. They are located
in the cytoplasm of the egg cell; i.e., in that part of the
(30) cell’s protoplasm that lies outside of the nucleus. In the
unfertilized egg, the substances are inactive and are not
distributed homogeneously. When the egg is fertilized,
the substances become active and, presumably, govern
the behavior of the genes they interact with. Since the
(35) substances are unevenly distributed in the egg, when the
fertilized egg divides, the resulting cells are different
from the start and so can be qualitatively different in
their own gene activity.
The substances that Gross studied are maternal
(40) messenger RNA’s --products of certain of the maternal
genes. He and other biologists studying a wide variety
of organisms have found that these particular RNA’s
direct, in large part, the synthesis of histones, a class
of proteins that bind to DNA. Once synthesized, the
(45) histones move into the cell nucleus, where section of
DNA wrap around them to form a structure that resem-
bles beads, or knots, on a string. The beads are DNA
segments wrapped around the histones; the string is the
intervening DNA. And it is the structure of these beaded
(50)DNA strings that guides the fate of the cells in which
they are located.
我的判断: 【套路】现象解释型
【逻辑简图】
提出现象:biologists found that if they separated an invertebrate animal embryo into two parts at an early stage of its life, it would survive and developas two normal embryos.(第一段第一句话)
错误解释:cells in the early embryo are undetermined in the sense that each cell has the potential to develop in a variety of different ways.(第一段第二句话)
质疑错误解释(第一段余下部分)
正确解释。。。后面不知道了。。。看不出来了
希望大家多讨论,相互帮助,共同进步!
【套路】现象解释型
【逻辑简图】
提出现象:biologists found that if they separated an invertebrate animal embryo into two parts at an early stage of its life, it would survive and developas two normal embryos.(第一段第一句话)
错误解释:cells in the early embryo are undetermined in the sense that each cell has the potential to develop in a variety of different ways.(第一段第二句话)
质疑错误解释(第一段余下部分)
正确解释。。。后面不知道了。。。看不出来了
希望大家多讨论,相互帮助,共同进步! |
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