During the process of embryonic development, cells become progressiv

Question

Project RC Butler 2020  -  Participate and win GMAT Club Tests.   
Passage # 140, Date: 09-Jun-2020
 This post is a part of Project RC Butler 2020 .  Click here for Details

During the process of embryonic development, cells become progressively restricted in their developmental potential and finally acquire the biochemical and morphological specialization necessary for their respective functions in an adult. Since enzymatic and structural proteins are required for the appearance and maintenance of this specialization, the differentiated state results from the synthesis and activity of cell-specific proteins during development.

Since all cells of an organism contain the same genotype as the fertilized egg, cellular differentiation is the result of variable gene activity rather than selective gene loss. Thus, cellular specialization and cell-specific protein synthesis result from the expression of appropriately selected groups of genes in each cell type. As development proceeds, the progressive differentiation of cells is correlated with changes in the population of protein species within the embryo, which in turn reflect the accurate programming of the time and sequence of the biosynthesis of different proteins by the genome. In the absence of opportunities for genetic analysis, determining the mechanisms involved in the regulation of protein synthesis is key to understanding genome control during development.

The majority of studies on gene activity in embryogenesis have been done on the sea urchin system, where large numbers of embryos undergoing relatively synchronous development can be easily obtained. Also, sea urchins’ permeability to radioactive isotopes and to inhibitors of RNA and protein synthesis provides a distinct advantage for study over amphibian material. Especially well documented are the maternal programming of early development and the genomic control of later differentiation in the urchin. Maternal products, stored in the egg cytoplasm from oogenesis, can support development from fertilization through the hatching blastula stage; however, development from the mesenchyme blastula stage is dependent upon gene products synthesized under the direction of the embryonic genome.    1 
 B 
 1. With which of the following statements would the author of the passage most likely disagree?

(A) Morphological specialization requires the synthesis of cell-specific proteins.
(B) Embryonic development involves differentiation in cell genotype.
(C) The population of protein species with the embryo is dependent upon the timing of protein biosynthesis.
(D) Enzymatic proteins are required for an organism’s full development.
(E) Selective gene loss is not a factor in cellular differentiation during embryonic development.

2 
 E 
 2. Which of the following statements about embryonic development in sea urchins is best supported by the passage?

(A) Genomic control over early embryonic development is especially well documented.
(B) Permeability to RNA inhibitors is comparable to that in amphibian embryos.
(C) Development during the hatching blastula stage requires gene products synthesized under the direction of the embryonic genome.
(D) Maternal products can support embryonic development following the mesenchyme blastula stage.
(E) Genomic control of later cell differentiation has been studied extensively

3 
 A 
 3. The last paragraph of the passage

(A) illustrates a biological process by way of an example.
(B) describes a methodology for studying a biological phenomenon.
(C) compares two stages of biological development.
(D) defines and explains an important term mentioned earlier.
(E) provides an example which disproves a scientific theory

Source:  Master GMAT

PhantomAY · Answer

This passage is hard in a way that contains too many technical Jargons, and asked 2 detail questions which are hard to locate precisely within time restriction. I only got the general question (last one) right and did make sense out of the other 2 during review, but still feel like this is a challenging one during real test though.

Below is my analysis on questions given enough time. Appreciate if experts can advise how to speed up the thinking process for this type of question (contains many details)  GMATNinja   workout   bb

Question 1 
(A) refers to 1st - "...biochemical and morphological specialization necessary for their respective functions in an adult. Since enzymatic and structural proteins are required for the appearance and maintenance of this specialization..."
(B) contradicting 2nd - "Since all cells of an organism contain the same genotype as the fertilized egg"
(C) refers to 2nd - "changes in the population of protein species within the embryo, which in turn reflect the accurate programming of the time and sequence of the biosynthesis of different proteins by the genome"
(D) refers to 1st - "Since enzymatic and structural proteins are required for the appearance and maintenance of this specialization"
(E) refers to 1st - "cellular differentiation is the result of variable gene activity rather than selective gene loss"

Question 2
(A) Genomic control doesn't dominate early earlyment but rather "later differentiation in the urchin"
(B) "is comparable to" contradicts "distinct advantage for study over amphibian material"
(C) its not the " hatching  blastula stage" but the " mesenchyme  blastula stage" that requires gene products synthesized under the direction of the embryonic genome 
(D) Maternal products cannot support after stage, refer to "however, development from the mesenchyme blastula stage is dependent upon gene products synthesized under the direction of the embryonic genome"
(E) Correct anwser, refer to "The majority of studies on gene activity in embryogenesis have been done on the sea urchin system" and "Especially well documented are the maternal programming of early development and the genomic control..."

Question 3
(A) illustrates a biological process by way of an example. - correct, use "sea urchin" as a perfect example to explain how genome controls protein/maternal products synthesized that impact development
(B) describes a methodology for studying a biological phenomenon. - it's hardly a methodology but just an example
(C) compares two stages of biological development. - the 2 stages are used as examples to describe the biological process, the purpose is not to compare them
(D) defines and explains an important term mentioned earlier. - the purpose is not to explain any term but to illustrate how X's (genomes, proteins,...) impacts the development process
(E) provides an example which disproves a scientific theory - it didn't disproves but rather help explain the process

arora1 · Answer

This does not resemble a gmat style passage. All three paragraphs are extremely dense. Though I got all three correct in less than 6 minutes( becuase i have studied bio ), the passage is full of technical information that is hard to understand imo.
Each question requires a careful and line by line scan of the passage

auradediligodo · Answer

Hello everyone

I agree with the previous posts. Under time constrictions this passage seems extremely dense and difficult to comprehend for those who don't have a clue about biology. Maybe a good approach here would be to spend less time on the reading part and more on the questions.

--------------------------------------------------------------------------------------------

P1

The first paragraph introduces the main topic:embryonic development. We are given that as soon as the development phase is over, a process of specialization occurs.
Lastly the author highlights the importance of cell specific proteins for the development.

Purpose:   to introduce the topic of embryonic development, talking about the phases of development and specialization

P2

The second paragraph starts with a cause effect scenario:
cause: all cells contain the same genotype as the one in the egg
effect: cellular differentiation comes from variable gene activity

The author therefore highlights the importance of gene activity for cellular specialization and protein synthesis.
Protein species within the embryo are then responsible for eventual changes, which in turn are related to genome control.
To understand genome control without performing a genetic analysis we should study the mechanisms related to protein synthesis.

Purpose:  To explain which processes are important for embryonic development and how to study them

P3

Here the author states the advantages of studying gene activity in sea urchins' systems. 3 factors represent an advantage to study sea urchins compared to other amphibians:
1 permeability to radioactive isotopes
2 permeability to inhibitors of RNA
3 protein synthesis

Purpose:   to explain the phenomenon of embryonic development by means of an example.

Main point

The main point of this passage is to explain embryonic development and the factors affecting it.

--------------------------------------------------------------------------------------------

1. With which of the following statements would the author of the passage most likely disagree?

Pre-thinking

inference question

we need to evaluate each option

(A) Morphological specialization requires the synthesis of cell-specific proteins.
 this option seems to be supported here: 
 the differentiated state results from the synthesis and activity of cell-specific proteins during development.

(B)   Embryonic development involves differentiation in cell genotype.
 it seems that the author would disagree with this statement based on the first sentence of the second paragraph:
 Since all cells of an organism contain the same genotype as the fertilized egg, cellular differentiation is the result of variable gene activity rather than selective gene loss.

(C) The population of protein species with the embryo is dependent upon the timing of protein biosynthesis.
 seems to be supported here
 As development proceeds, the progressive differentiation of cells is correlated with changes in the population of protein species within the embryo, which in turn reflect the accurate programming of the time and sequence of the biosynthesis of different proteins by the genome.

(D) Enzymatic proteins are required for an organism’s full development.
 supported here:
 Since enzymatic and structural proteins are required for the appearance and maintenance of this specialization,

(E) Selective gene loss is not a factor in cellular differentiation during embryonic development.
 supported here:
 cellular differentiation is the result of variable gene activity rather than selective gene loss.

--------------------------------------------------------------------------------------------

2. Which of the following statements about embryonic development in sea urchins is best supported by the passage?

Pre-thinking

Inference question

We need to refer to the last paragraph to answer this question

(A) Genomic control over early embryonic development is especially well documented.
 Something similar but different in meaning is written along these lines:
 Especially well documented are the maternal programming of early development and the genomic control of later differentiation in the urchin

(B) Permeability to RNA inhibitors is comparable to that in amphibian embryos.
 Cannot be inferred

(C) Development during the hatching blastula stage requires gene products synthesized under the direction of the embryonic genome.
 This option would be correct if talking about the   mesenchyme blastula stage

(D) Maternal products can support embryonic development following the mesenchyme blastula stage.
 Similarly to the previous option, option d would be correct if instead of mentioning the mesenchyme blastula stage would mention the hatching blastula stage

(E)   Genomic control of later cell differentiation has been studied extensively
 Correct thanks to POE but let's see the actual reasons.
From these lines we can infer option E:
 Especially well documented are the maternal programming of early development and the genomic control of later differentiation in the urchin.

--------------------------------------------------------------------------------------------

3. The last paragraph of the passage

Pre-thinking

Inference question

We need to evaluate the options

(A)   illustrates a biological process by way of an example.
 In line with paragraph summary.

(B) describes a   methodology   for studying a biological phenomenon.

(C)   compares   two stages of biological development.
(D)  defines and explains an important term mentioned earlier. 
(E) provides an example which   disproves   a scientific theory

--------------------------------------------------------------------------------------------

It is a great day to be alive!

richirish · Answer

What a passage, definitely 750 level imo, took me 7.5 mins to read and answer all correctly, would recommend everyone eyeing a Q45 to give it a shot! If that's not what you are targeting, don't be hard on yourselves, this is a very difficult passage.

VerbalBot · Answer

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.

During the process of embryonic development, cells become progressiv

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Reading Comprehension (RC) Questions

During the process of embryonic development, cells become progressiv

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards