SAT文章閱讀模擬題之embryo cells
下面為大家推薦的是一篇SAT文章閱讀模擬題的相關內容，后面附有題目正確答案。這是一篇關于embryo cells 的SAT閱讀文章，篇幅不是很長，題目量也不大。下面大家就和小編一起來看看這篇模擬題的詳細內容吧。
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 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 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 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 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 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 cells 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 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 messenger RNAs --products of certain of the maternal genes. He and other biologists studying a wide variety of organisms have found that these particular RNAs direct, in large part, the synthesis of histones, a class of proteins that bind to DNA. Once synthesized, the 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 DNA strings that guides the fate of the cells in which they are located.
1. The passage is most probably directed at which kind of audience?
State legislators deciding about funding levels for a state-funded biological laboratory
Scientists specializing in molecular genetics
Readers of an alumni newsletter published by the college that Paul Gross attended
Marine biologists studying the processes that give rise to new species
Undergraduate biology majors in a molecular biology course
2. It can be inferred from the passage that the morphogenetic determinants present in the early embryo are
located in the nucleus of the embryo cells
evenly distributed unless the embryo is not developing normally
inactive until the embryo cells become irreversibly committed to their final function
identical to those that were already present in the unfertilized egg
present in larger quantities than is necessary for the development of a single individual
3. The main topic of the passage is
the early development of embryos of lower marine organisms
the main contribution of modern embryology to molecular biology
the role of molecular biology in disproving older theories of embryonic development
cell determination as an issue in the study of embryonic development
scientific dogma as a factor in the recent debate over the value of molecular biology
4. According to the passage, when biologists believed that the cells in the early embryo were undetermined, they made which of the following mistakes?
They did not attempt to replicate the original experiment of separating an embryo into two parts.
They did not realize that there was a connection between the issue of cell determination and the outcome of the separation experiment.
They assumed that the results of experiments on embryos did not depend on the particular animal species used for such experiments.
They assumed that it was crucial to perform the separation experiment at an early stage in the embryos life.
They assumed that different ways of separating an embryo into two parts would be equivalent as far as the fate of the two parts was concerned.
5. It can be inferred from the passage that the initial production of histones after an egg is fertilized takes place
in the cytoplasm
in the maternal genes
throughout the protoplasm
in the beaded portions of the DNA strings
in certain sections of the cell nucleus
6. It can be inferred from the passage that which of the following is dependent on the fertilization of an egg?
Copying of maternal genes to produce maternal messenger RNAs
Sythesis of proteins called histones
Division of a cell into its nucleus and the cytoplasm
Determination of the egg cells potential for division
Generation of all of a cells morphogenetic determinants
7. According to the passage, the morphogenetic determinants present in the unfertilized egg cell are which of the following?
Proteins bound to the nucleus
Histones
Maternal messenger RNAs
Cytoplasm
Nonbeaded intervening DNA
8. The passage suggests that which of the following plays a role in determining whether an embryo separated into two parts will two parts will develop as two normal embryos?
Ⅰ.The stage in the embryos life at which the separation occurs
Ⅱ. The instrument with which the separations is accomplished
Ⅲ. The plane in which the cut is made that separates the embryo
Ⅰonly
Ⅱ only
Ⅰ and Ⅱ.only
Ⅰ and Ⅲ.only
Ⅰ,Ⅱ, and Ⅲ
9. Which of the following circumstances is most comparable to the impasse biologists encountered in trying to resolve the debate about cell determination ?
The problems faced by a literary scholar who wishes to use original source materials that are written in an unfamiliar foreign language
The situation of a mathematician who in preparing a proof of a theorem for publication detects a reasoning error in the proof
The difficulties of a space engineer who has to design equipment to function in an environment in which it cannot first be tested
The predicament of a linguist trying to develop a theory of language acquisition when knowledge of the structure of language itself is rudimentary at best
The dilemma confronting a foundation when the funds available to it are sufficient to support one of two equally deserving scientific projects but not both
Correct Answers：EEDEABCDD
以上就是這篇SAT文章閱讀模擬題的全部內容，正確答案沒有解析。大家在備考自己的SAT文章閱讀的過程中，多做一些模擬題是非常好的方式，這樣可以讓自己更快更好的適應SAT閱讀考試的出題方式和答題方法等。
下面為大家推薦的是一篇SAT文章閱讀模擬題的相關內容，后面附有題目正確答案。這是一篇關于embryo cells 的SAT閱讀文章，篇幅不是很長，題目量也不大。下面大家就和小編一起來看看這篇模擬題的詳細內容吧。
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 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 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 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 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 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 cells 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 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 messenger RNAs --products of certain of the maternal genes. He and other biologists studying a wide variety of organisms have found that these particular RNAs direct, in large part, the synthesis of histones, a class of proteins that bind to DNA. Once synthesized, the 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 DNA strings that guides the fate of the cells in which they are located.
1. The passage is most probably directed at which kind of audience?
State legislators deciding about funding levels for a state-funded biological laboratory
Scientists specializing in molecular genetics
Readers of an alumni newsletter published by the college that Paul Gross attended
Marine biologists studying the processes that give rise to new species
Undergraduate biology majors in a molecular biology course
2. It can be inferred from the passage that the morphogenetic determinants present in the early embryo are
located in the nucleus of the embryo cells
evenly distributed unless the embryo is not developing normally
inactive until the embryo cells become irreversibly committed to their final function
identical to those that were already present in the unfertilized egg
present in larger quantities than is necessary for the development of a single individual
3. The main topic of the passage is
the early development of embryos of lower marine organisms
the main contribution of modern embryology to molecular biology
the role of molecular biology in disproving older theories of embryonic development
cell determination as an issue in the study of embryonic development
scientific dogma as a factor in the recent debate over the value of molecular biology
4. According to the passage, when biologists believed that the cells in the early embryo were undetermined, they made which of the following mistakes?
They did not attempt to replicate the original experiment of separating an embryo into two parts.
They did not realize that there was a connection between the issue of cell determination and the outcome of the separation experiment.
They assumed that the results of experiments on embryos did not depend on the particular animal species used for such experiments.
They assumed that it was crucial to perform the separation experiment at an early stage in the embryos life.
They assumed that different ways of separating an embryo into two parts would be equivalent as far as the fate of the two parts was concerned.
5. It can be inferred from the passage that the initial production of histones after an egg is fertilized takes place
in the cytoplasm
in the maternal genes
throughout the protoplasm
in the beaded portions of the DNA strings
in certain sections of the cell nucleus
6. It can be inferred from the passage that which of the following is dependent on the fertilization of an egg?
Copying of maternal genes to produce maternal messenger RNAs
Sythesis of proteins called histones
Division of a cell into its nucleus and the cytoplasm
Determination of the egg cells potential for division
Generation of all of a cells morphogenetic determinants
7. According to the passage, the morphogenetic determinants present in the unfertilized egg cell are which of the following?
Proteins bound to the nucleus
Histones
Maternal messenger RNAs
Cytoplasm
Nonbeaded intervening DNA
8. The passage suggests that which of the following plays a role in determining whether an embryo separated into two parts will two parts will develop as two normal embryos?
Ⅰ.The stage in the embryos life at which the separation occurs
Ⅱ. The instrument with which the separations is accomplished
Ⅲ. The plane in which the cut is made that separates the embryo
Ⅰonly
Ⅱ only
Ⅰ and Ⅱ.only
Ⅰ and Ⅲ.only
Ⅰ,Ⅱ, and Ⅲ
9. Which of the following circumstances is most comparable to the impasse biologists encountered in trying to resolve the debate about cell determination ?
The problems faced by a literary scholar who wishes to use original source materials that are written in an unfamiliar foreign language
The situation of a mathematician who in preparing a proof of a theorem for publication detects a reasoning error in the proof
The difficulties of a space engineer who has to design equipment to function in an environment in which it cannot first be tested
The predicament of a linguist trying to develop a theory of language acquisition when knowledge of the structure of language itself is rudimentary at best
The dilemma confronting a foundation when the funds available to it are sufficient to support one of two equally deserving scientific projects but not both
Correct Answers：EEDEABCDD
以上就是這篇SAT文章閱讀模擬題的全部內容，正確答案沒有解析。大家在備考自己的SAT文章閱讀的過程中，多做一些模擬題是非常好的方式，這樣可以讓自己更快更好的適應SAT閱讀考試的出題方式和答題方法等。
