OG48-5(實在是太難懂，讓我們一起突破困境)

[agk99]

Passage 5

太難懂，突顯我閱讀功力還是不行，請教本篇大家的解法

Nearly a century ago, biologists found that if they separated an invertebrate(無脊髓動物) animal embryo(胚胎) 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(重要訊號字，以後半段為主) biologists found that the situation was not so simple. It matters(關鍵) 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.
第一段總結：(雖然是一篇蠻莫名其妙的文章)，就是講一個胚胎的概念，這胚胎若被一分為二，仍會長成完整的兩個胚胎。但現在新的發現指出，胡亂切成兩個胚胎不見得能分成兩個，要像以前研究人員切的平面，才能完成兩個胚胎。

A debate arose over what exactly was happening. Which embryo cells are determined(哪些胚胎細胞是確定的?), just when do they-become irreversibly committed to their fates(什麼時候這些胚胎才會出現一種不可逆轉的命運？), and what are the “morphogenetic determinants(型態發生認定物?)” that tell a cell what to become(而這些形態發生又傳達了細胞要轉變為什麼)?讀到這種句子，你會變得沒有信心，到底現在是怎樣，這種問題順便請教大家如何克服。 But(第一次轉折(對比前面三個問題，無人能解決) 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(講的是沒有人能解決這個問題). Recent discoveries in molecular biology, however(第二次對比，強調原本是沒人解決，現在則是有了解決曙光), have opened up prospects for a resolution of the debate然而在最近在分子生物學中發現有一絲解決爭論的希望. Now investigators think they know at least some of the molecules that act as morphogenetic determinants(型態發生認定物?)in early development. They have been able to show that, in a sense(在某種意義上), cell determination begins even before an egg is fertilized(細胞決定?開始於甚至早於蛋的孵化).(真的還是不太了解在寫什麼)
第二段總結：爭論很多，但一直沒有定論，這是因為沒有一位生物學家能突破爭論點，但由於一些MD分子的出現，導致細胞的的決定在很早期就開始了。

Studying sea urchins(海膽), biologist Paul Gross found that an unfertilized egg contains substances that function as morphogenetic determinants(型態發生認定物?). They are located in the cytoplasm (細胞質) of the egg cell; i.e., in that part of the cell’s protoplasm (原生質) that lies outside of the nucleus. In the unfertilized egg,(尚未孵化的蛋) the substances are inactive(不活躍) and are not distributed homogeneously(分布混雜地). When the egg is fertilized在受精之後, the substances(含有MD的物質) become active and, presumably, govern the behavior of the genes they interact with(與基因之間的交互作用). Since the substances are unevenly distributed(並未均勻分配) in the egg, when the fertilized egg divides(當受精的蛋分裂時)，, the resulting cells are different from the start and so can be qualitatively(性質地) different in their own gene activity(基因活動上).
第三段總結：明確指出細胞在未受精前，就己含有MD這種物質，一旦細胞被受精，這些物質就會變得active，而且會激發和基因之間的相互活動。

The substances that Gross studied are maternal messenger RNA’s(核糖核酸) --products of certain of the maternal genes(特定母性基因的產物). 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(組織蛋白), a class of proteins that bind to DNA(脫氧核糖核酸). Once synthesized, the histones move into the cell nucleus, where section of DNA wrap(包裹) around them(成組的DNA將其包裹) to form a structure that resembles beads(念珠), or knots(節), on a string(繩). The beads are DNA segments wrapped around the histones珠子就是包裹在組織蛋白之外的DNA斷片; the string is the intervening DNA(繩結則是居間的DNA). And it is the structure of these beaded DNA strings that guides the fate of the cells in which they are located(就是這些念珠及繩結構的DNA引導細胞所在位置的命運).
第四段總結：從第三段引出MD的特質，就是激發RNA與DNA的重要物質


*25. It can be inferred from the passage that the morphogenetic determinants present in the early embryo are (推論題)
(A) located in the nucleus of the embryo cells 明顯與原文不符，事實上，MD是在細胞質中
(B) evenly distributed unless the embryo is not developing normally 不均勻才對
(C) inactive until the embryo cells become irreversibly committed to their final function 活躍才對
(D) identical to those that were already present in the unfertilized egg 文中未提及
(E) present in larger quantities than is necessary for the development of a single individual
我做錯了，答案E，但想不通是如何推論的

26. The main topic of the passage is
(A) the early development of embryos of lower marine organisms
(B) the main contribution of modern embryology to molecular biology
(C) the role of molecular biology in disproving older theories of embryonic development
(D) cell determination as an issue in the study of embryonic development
(E) scientific dogma as a factor in the recent debate over the value of molecular biology

27. According to the passage, when biologists believed that the cells in the early embryo were undetermined, they made which of the following mistakes?(細節題)
(A) They did not attempt to replicate the original experiment of separating an embryo into two parts.
(B) They did not realize that there was a connection between the issue of cell determination and the outcome of the separation experiment.
(C) They assumed that the results of experiments on embryos did not depend on the particular animal species used for such experiments.
(D) They assumed that it was crucial to perform the separation experiment at an early stage in the embryo’s life.
(E) 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.(直接抓第一段)

*28. It can be inferred from the passage that the initial production of histones(組織蛋白) after an egg is fertilized takes place
(A) in the cytoplasm
(B) in the maternal genes
(C) throughout the protoplasm
(D) in the beaded portions of the DNA strings
(E) in certain sections of the cell nucleus???
我又選錯了，答案是A，理由是在本文第四段，指出histones是RNA組織支配而成，這題真的是沒輒了，經過比較仔細的比較後，發現第四段提的都是在講MD所蘊含的物質，而這個物質，則是來自第三段一開始的敘述。

*29. It can be inferred from the passage that which of the following is dependent on the fertilization of an egg?
(A) Copying of maternal genes to produce maternal messenger RNA’s
(B) Sythesis of proteins called histones
(C) Division of a cell into its nucleus and the cytoplasm
(D) Determination of the egg cell’s potential for division
(E) Generation of all of a cell’s morphogenetic determinants
答案B

*30. According to the passage, the morphogenetic determinants present in the unfertilized egg cell are which of the following?
(A) Proteins bound to the nucleus
(B) Histones
(C) Maternal messenger RNA’s
(D) Cytoplasm
(E) Nonbeaded intervening DNA
答案C

[魚]

報告 ~~

agk 大哥 , 魚 嚴重建議你 要把指導兩個字拿掉

不然 ~~ 沒人敢回帖 ^^

[agk99]

來了來了
我己經調整了用詞，歡迎大家幫忙

[訪客]

*25. It can be inferred from the passage that the morphogenetic determinants present in the early embryo are (推論題)
(A) located in the nucleus of the embryo cells 明顯與原文不符，事實上，MD是在細胞質中
(B) evenly distributed unless the embryo is not developing normally 不均勻才對
(C) inactive until the embryo cells become irreversibly committed to their final function 活躍才對
(D) identical to those that were already present in the unfertilized egg 文中未提及
(E) present in larger quantities than is necessary for the development of a single individual
我做錯了，答案E，但想不通是如何推論的
=>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 productivelyI suppoes, but I am not sure because I also did wrong.
]

[agk99]

*25. It can be inferred from the passage that the morphogenetic determinants present in the early embryo are (推論題)
(A) located in the nucleus of the embryo cells 明顯與原文不符，事實上，MD是在細胞質中
(B) evenly distributed unless the embryo is not developing normally 不均勻才對
(C) inactive until the embryo cells become irreversibly committed to their final function 活躍才對
(D) identical to those that were already present in the unfertilized egg 文中未提及
(E) present in larger quantities than is necessary for the development of a single individual
我做錯了，答案E，但想不通是如何推論的
=>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 productivelyI suppoes, but I am not sure because I also did wrong.
]

這一題我今天再進一步想想，題目問embryo的早期有何特徵，讓我只能找第一段定位，（第一段講的是尚未fertilized的蛋，是一種可切割的胚胎型式）
因此，這些胚胎既然切開後仍然可以完成受精，那麼這種MD肯定是數量很多的。
我的想法，請有練習過或做過的同學給我點意見吧

[訪客]

Someone answer this question in CD.
I paste it as follwed.
e有味道.就是第一段.科学家分开受精卵而能够发育为两个独立的胚胎,吧e取非,就和文章矛盾了.所以e对.

[illuna]

這一題我今天再進一步想想，題目問embryo的早期有何特徵，讓我只能找第一段定位，（第一段講的是尚未fertilized的蛋，是一種可切割的胚胎型式）
因此，這些胚胎既然切開後仍然可以完成受精，那麼這種MD肯定是數量很多的。
我的想法，請有練習過或做過的同學給我點意見吧

我不知道我的解法能不能做這一題....先野人獻曝一下...請大家指導指導....


Nearly a century ago (表過去理論是怎樣…可以預期往下讀會看到現在理論是怎樣…而且以現在為主) , biologists found (科學性文章發現的結果是重點……that子句必讀) that if (if子句帶進前提=因…主要子句=果) 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 (表old(theory)：one embryo(cut in early stage)-->two embryo) led (因果關係…前面是因後面是果) them to believe that the cells (新的說明主題的細節) in the early embryo are undetermined in the sense (在某種程度上) that each cell has the potential to develop in a variety of different ways. (整理一下得到的因果關係old(theory)：one embryo(cut in early stage)--> two embryo-->cell undetermined) Later (現在理論出現) biologists found (發現結果必讀) 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. (表現在跟過去的不同點 new(theory)：one embyro(cut in the right plane)-->two embryo-->cell determined(隱含))

1st：embryo(cut in the right plane)-->two embryo,but how?)

(預期在本段應該有解釋為何發生1st的現象) 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(=determine) ? (設問手法重點在於答案而非問題本身….略讀…僅注意問題的疑問詞…which…when…what are MD(新細節)以及往下文章中回答此類問題的句子) But (語氣轉折以後為主) the debate could not be resolved because (因果關係後面接因) no one was able to ask the crucial questions in a form in which they could be pursued productively. Recent discoveries in molecular biology (新細節…前面從未提過) , however (語氣轉折…前面態度N後面就應該是P) , 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 (=early stage) . They have been able o show (發現結果…必讀) that, in a sense, cell determination begins even before an egg is fertilized (=early stage…只解釋了前面問題中的when) .

(更具體的例子接著說明2nd在分子生物學的發現) Studying sea urchins, biologist Paul Gross found that an unfertilized egg (=early stage) contains substances that function as morphogenetic determinants. (至此知道後面將說明了2nd中what are MD) They are located (後面所接點出MD的位置) in the cytoplasm of the egg cell; i.e., in that part of the cell’s protoplasm that lies outside of the nucleus. In the unfertilized egg (=early stage) , the substances are inactive and are not distributed homogeneously (在early stage時MD的性質) . When the egg is fertilized, (=irreversible) the substances become active and, presumably, govern the behavior of the genes they interact with (在irreversible時MD的性質) . Since the substances are unevenly distributed (=not distributed homogeneously) 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.

(再更進一步說明3rd中的MD是什麼) The substances that Gross studied are maternal messenger RNA’s (=MD) --products of certain of the maternal genes. He and other biologists studying a wide variety of organisms have found (發現結果必讀) that these particular RNA’s direct (這裡當動詞用) , in large part, the synthesis of histones, a class of proteins that bind to DNA. (表definition手法…histones= protein bind to DNA) (在這邊整理一下…Maternal gene-->MD(RNA)-->histone)Once synthesized, the histones move into the cell nucleus, where section of DNA wrap around them to form a structure that resembles 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.
(histone-->DNA-->Cell fate(=determined))



這篇文章的結構....specific to general to specific

徐老師說過...說明細節的細節可以跳過....說明主題的細節就千萬要讀

推論題考的是indirect message...

agk阿哥...老實說這篇我看了不下十遍...Q25仍然解不太出來....或許等徐老師解到這篇的時候我再去問問...

後來看了OG的解釋我認為是挺有道理的....只是我希望能向徐老師的模式解題...

累了....去睡覺.....

[魚]

這篇文章的結構....specific to general to specific

徐老師說過...說明細節的細節可以跳過....說明主題的細節就千萬要讀

推論題考的是indirect message...

agk阿哥...老實說這篇我看了不下十遍...Q25仍然解不太出來....或許等徐老師解到這篇的時候我再去問問...

後來看了OG的解釋我認為是挺有道理的....只是我希望能向徐老師的模式解題...

累了....去睡覺.....

後來看了OG的解釋我認為是挺有道理的.... ;) 同意 ^^

BTW , 記得嗎 ?老師說 inferred 題用 attitude 刪答案

這題ETS考刁了 ~ 有點像CR的inferred 題 ^^

我覺得OG 上ETS的自圓其說圓得還不賴

反正其他答案都錯的很明顯.....就 接受吧 :P

[shihyingho]

想請問一下25題答案C為什麼不對呀?文章是說In the unfertilized egg (=early stage) , the substances are inactive and are not distributed homogeneously (在early stage時MD的性質) . When the egg is fertilized, (=irreversible) the substances become active也就是MD在早期是inactive,fertilized(irreversible)之後就變active.不就跟答案c說的一樣嗎?(MD present in the early embryo are inactive until the embryo cells become irreversibly committed to their final funtion)

[davidlee0222]

看看大衛的水上飄有沒有比較快~

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.
看起來好像差不多快，主要因為本段資訊都很重要，其實很簡單，就在講以前人搞錯了，只要切面不同，就會變複製。相當神奇，下段必講哪裡有問題。

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 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 to show that, in a sense, cell determination begins even before an egg is fertilized
也相當簡單，而且用水上飄出現加速，因為訊息有些是廢話
就在講之前爭論是因為根本搞錯研究方向
終於有人證實在授精前就決定胚胎命運
如何決定呢? 必於下段解說


Studying sea urchins, biologist Paul Gross found that an unfertilized egg contains substances that function as morphogenetic determinants. They are located in the cytoplasm of the egg cell; i.e., in that part of the 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 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

原來有個東西會不一樣

The substances that Gross studied are maternal 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 histones move into the cell nucleus, where section of DNA wrap around them to form a structure that resembles beads(念珠), or knots(節), on a string(繩). 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

出現大幅加速
原來就是RNA
中間都在講它長啥樣
只有一句重點是中間那句
"一旦合成，H會一到CN裡
改變它的命運"
全文結束
其實是相當簡單的文章
就在講以前切錯方向
然後有切到一個東西就會複製
沒切到就不會

[shine822]

我想問的是
*29. It can be inferred from the passage that which of the following is dependent on the fertilization of an egg?
(A) Copying of maternal genes to produce maternal messenger RNA’s
(B) Sythesis of proteins called histones
(C) Division of a cell into its nucleus and the cytoplasm
(D) Determination of the egg cell’s potential for division
(E) Generation of all of a cell’s morphogenetic determinants

我將 ACE 用 not mention 排除，
D 則是因 24 行 所以 cell determination is before fertilization 來排除
降解，不曉得正不正確？

可是 B 我還是完全參不透，因為OG解答明明是寫對照 30-34行 morphogenetic determination are inactive in the unfertilized egg and that when the egg is fertilized, they "become active and, presumbably, govern the behavior of the genes thay interact with."
但要如何推論到 43 行的 the synthesis of histones？？？


請大大相救！

[davidlee0222]

本題用排除法必死
誰是誰的dependant
提問誰靠卵授精決定
文中有講未受精前
histone不會動
授精後histone會跑進細胞核
直接就要砍B
沒有再讓你回文的
機考第四篇看不到不會上600

[davidlee0222]

哪裡有推論?
B就是histone

[davidlee0222]

文章裡看到histone移動時
就要想到會考是什麼因素讓他移動
就是授精這件事
題目只是反過來問

[shine822]

文章裡看到histone移動時
就要想到會考是什麼因素讓他移動
就是授精這件事
題目只是反過來問

非常感謝大衛大大的飛快回帖！！！

不過我想我除了英文差之外，生物白癡的我
完全看不出來
所謂的 When the egg is fertilized, the substances (morphogenetic determinants) become active. (活躍的？） 跟 once synthesized, the histones move （移動）into the cell nuclsus.
這是指同一件事嗎？

還是您用其他句作判斷根據呢？

P.S 我大概會成為你口中看不到第四篇的那種人，閱讀速度真是慢得驚人...... 唉∼我快要考了......