Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 23 May 2017, 17:33

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Nearly a century ago, biologists found that if they

Author Message
TAGS:

### Hide Tags

Manager
Joined: 18 Jun 2004
Posts: 103
Location: san jose , CA
Followers: 2

Kudos [?]: 88 [1] , given: 0

Nearly a century ago, biologists found that if they [#permalink]

### Show Tags

19 Feb 2005, 17:37
1
KUDOS
1
This post was
BOOKMARKED
Question 1
00:00

Question Stats:

44% (00:00) correct 56% (00:00) wrong based on 9

### HideShow timer Statistics

Question 2
00:00

Question Stats:

15% (00:00) correct 85% (00:10) wrong based on 13

### HideShow timer Statistics

Question 3
00:00

Question Stats:

78% (00:00) correct 22% (00:00) wrong based on 9

### HideShow timer Statistics

Question 4
00:00

Question Stats:

56% (00:00) correct 44% (00:11) wrong based on 9

### HideShow timer Statistics

Question 5
00:00

Question Stats:

29% (00:00) correct 71% (00:00) wrong based on 7

### HideShow timer Statistics

Question 6
00:00

Question Stats:

25% (00:00) correct 75% (00:00) wrong based on 8

### HideShow timer Statistics

Question 7
00:00

Question Stats:

50% (00:00) correct 50% (00:00) wrong based on 8

### HideShow timer Statistics

Question 8
00:00

Question Stats:

75% (01:08) correct 25% (00:00) wrong based on 8

### HideShow timer Statistics

Question 9
00:00

Question Stats:

50% (01:25) correct 50% (02:54) wrong based on 8

### HideShow timer Statistics

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 to 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 function as morphogenetic determinants. They are located in the cytoplasm of the egg cell; i.e., in that part of the cellÂ¡Â¯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.

The substances that Gross studied are maternal messenger products of certain of the maternal genes. He and other biologists studying a wide variety of organisms have found that these particular RNAÂ¡Â¯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, 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 guide the fate of the cells in which they are located.
1. The passage is most probably directed at which kind of audience?
(A) State legislators deciding about funding levels for a state-funded biological laboratory
(B) Scientists specializing in molecular genetics
(D) Marine biologists studying the processes that give rise to new species
(E) Undergraduate biology majors in a molecular biology course

[Reveal] Spoiler:
E

2. It can be inferred from the passage that the morphogenetic determinants present in the early embryo are
(A) located in the nucleus of the embryo cells
(B) evenly distributed unless the embryo is not developing normally
(C) inactive until the embryo cells become irreversibly committed to their final function
(D) identical to those that were already present in the unfertilized egg
(E) present in larger quantities than is necessary for the development of a single individual

[Reveal] Spoiler:
E

3. 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

[Reveal] Spoiler:
D

4. According to the passage, when biologists believed that the cells in the early embryo were undetermined, they made which of the following mistakes?
(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.

[Reveal] Spoiler:
E

5. It can be inferred from the passage that the initial production of histones 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

[Reveal] Spoiler:
A

6. 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
(B) Synthesis 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

[Reveal] Spoiler:
B

7. 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 RNAÂ¡Â¯s
(D) Cytoplasm

[Reveal] Spoiler:
C

8. The passage suggests that which of the following plays a role in determining whether an embryo separated into two parts will develop as two normal embryos?
I. The stage in the embryoÂ¡Â¯s 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
(A) I only
(B) II only
(C) I and II only
(D) I and III only
(E) I, II, and III

[Reveal] Spoiler:
D

9. Which of the following circumstances is most comparable to the impasse biologists encountered in trying to resolve the debate about cell determination (as in the highlighted portion)?
(A) The problems faced by a literary scholar who wishes to use original source materials that are written in an unfamiliar foreign language
(B) The situation of a mathematician who in preparing a proof of a theorem for publication detects a reasoning error in the proof
(C) The difficulties of a space engineer who has to design equipment to function in an environment in which it cannot first be tested
(D) 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
(E) 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

[Reveal] Spoiler:
D

[Reveal] Spoiler: Question #1 OA
[Reveal] Spoiler: Question #2 OA
[Reveal] Spoiler: Question #3 OA
[Reveal] Spoiler: Question #4 OA
[Reveal] Spoiler: Question #5 OA
[Reveal] Spoiler: Question #6 OA
[Reveal] Spoiler: Question #7 OA
[Reveal] Spoiler: Question #8 OA
[Reveal] Spoiler: Question #9 OA

_________________

---- Hero never chooses Destiny
Destiny chooses Him ......

Last edited by MacFauz on 11 Mar 2014, 23:05, edited 2 times in total.
Formatting
If you have any questions
New!
Director
Joined: 18 Feb 2005
Posts: 670
Followers: 1

Kudos [?]: 6 [0], given: 0

### Show Tags

26 Feb 2005, 14:49
19 mins

6/9 correct.

Biology is a scare for me anyday....

Thanks for sharing the time and your score. I was shaken by the answers initially and then by my timing and ofcourse my score too.
Intern
Joined: 03 Oct 2013
Posts: 2
GMAT Date: 03-14-2014
Followers: 0

Kudos [?]: 0 [0], given: 2

Re: Nearly a century ago, biologists found that if they [#permalink]

### Show Tags

10 Mar 2014, 23:58
For 2nd question why E ,not A. it says hiostones move to the nucleus and determine th cell determination ,histones secreted fromm rna o basically morphognic dterminats are in nucleus where thy combine with dna.
Moderator
Joined: 02 Jul 2012
Posts: 1223
Location: India
Concentration: Strategy
GMAT 1: 740 Q49 V42
GPA: 3.8
WE: Engineering (Energy and Utilities)
Followers: 124

Kudos [?]: 1483 [1] , given: 116

Re: Nearly a century ago, biologists found that if they [#permalink]

### Show Tags

11 Mar 2014, 23:32
1
KUDOS
Passage wrote:
They are located in the cytoplasm of the egg cell. That part of the cell's protoplasm that lies outside of the nucleus

A is wrong for this reason. The passage clearly says that in the EARLY EMBRYO the morphological determinants lie outside the nucleus.

POE clearly eliminates all other answer choices since all answer choices are not neutral but rather contradictory to what is said in the passage. The only answer we are left with is E.

Passage wrote:
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 statement from the passage serves as the reasoning behind picking E as the right answer.

For 2nd question why E ,not A. it says hiostones move to the nucleus and determine th cell determination ,histones secreted fromm rna o basically morphognic dterminats are in nucleus where thy combine with dna.

_________________

Did you find this post helpful?... Please let me know through the Kudos button.

Thanks To The Almighty - My GMAT Debrief

GMAT Reading Comprehension: 7 Most Common Passage Types

Intern
Joined: 02 Nov 2013
Posts: 10
Followers: 1

Kudos [?]: 3 [0], given: 139

Re: Nearly a century ago, biologists found that if they [#permalink]

### Show Tags

17 Mar 2014, 00:22
16 minutes
Got 8/9 correct
Intern
Joined: 23 Dec 2013
Posts: 13
Followers: 0

Kudos [?]: 0 [0], given: 2

Re: Nearly a century ago, biologists found that if they [#permalink]

### Show Tags

17 Mar 2014, 05:57
6/9 13 minutes....

Not tough passage but lots of inferable questions.
Manager
Joined: 24 Jul 2011
Posts: 236
Location: India
GMAT 1: 570 Q50 V19
GMAT 2: 650 Q49 V28
GMAT 3: 690 Q50 V34
WE: Information Technology (Investment Banking)
Followers: 1

Kudos [?]: 45 [0], given: 93

Re: Nearly a century ago, biologists found that if they [#permalink]

### Show Tags

09 Aug 2014, 21:39
In Question 2, para 2 last line states that cell determination begins even before the fertilization of eggs is started. Therefore, option D that unfertilized and fertilized eggs both must be identical.

Where is the reasoning going wrong?
_________________

Middle of nowhere!

GMAT Club Legend
Joined: 01 Oct 2013
Posts: 10370
Followers: 996

Kudos [?]: 224 [0], given: 0

Re: Nearly a century ago, biologists found that if they [#permalink]

### Show Tags

10 Sep 2015, 00:53
Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Manager
Joined: 30 Oct 2010
Posts: 52
Followers: 1

Kudos [?]: 24 [0], given: 23

Re: Nearly a century ago, biologists found that if they [#permalink]

### Show Tags

11 Sep 2015, 03:34
rohitmanglik wrote:
In Question 2, para 2 last line states that cell determination begins even before the fertilization of eggs is started. Therefore, option D that unfertilized and fertilized eggs both must be identical.

Where is the reasoning going wrong?

Hi Rohit,

The question is about the morphogenetic componenents and hence they could be in different states inspite of being identical in number.

Also though the components of unfertilized and fertilized eggs are the same,they need not be identical.definitely the components would have undegone some change

after fetilization of the egg.Hope this helps
Re: Nearly a century ago, biologists found that if they   [#permalink] 11 Sep 2015, 03:34
Similar topics Replies Last post
Similar
Topics:
3 Nearly a century ago, biologists found that if they s 5 19 May 2017, 21:51
1 Nearly a century ago, biologists found that if they 6 13 Jul 2016, 04:42
Nearly a century ago, biologists found that if they 1 29 Apr 2013, 21:09
1 Nearly a century ago, biologists found that if they 4 13 Aug 2015, 05:55
40 Nearly a century ago, biologists found that if they separate 28 26 Sep 2016, 10:25
Display posts from previous: Sort by