Nearly twenty years ago, biochemists found that a separable constituen

Question

Nearly twenty years ago, biochemists found that a separable constituent of deoxyribonucleic acid (or DNA) appeared to guide the cell’s protein-synthesizing machinery. The internal structure of DNA seemed to represent a set of coded instructions which dictated the pattern of protein-synthesis. Experiments indicated that in the presence of appropriate enzymes each DNA molecule could form a replica, a new DNA molecule, containing the specific guiding message present in the original. This idea, when added to what was already known about the cellular mechanisms of heredity (especially the knowledge that DNA is localized in chromosomes), appeared to establish a molecular basis for inheritance.

Proponents of the theory that DNA was a “self-duplicating” molecule, containing a code that by itself determined biological inheritance, introduced the term “central dogma” into scientific literature. They did so in order to describe the principles that could explain DNA’s governing role. The dogma originally involved an admittedly unproven assumption that, whereas nucleic acids can guide the synthesis of other nucleic acids and of proteins, the reverse effect is impossible; that is, proteins cannot guide the synthesis of nucleic acids. But actual experimental observations deny the second and crucial part of this assumption. Other test-tube experiments show that agents besides DNA have a guiding influence. The kind of protein that is made may depend on the specific organism from which the necessary enzyme is obtained. It also depends on the test tube’s temperature, the degree of acidity, and the amount of metallic salts present.

The central dogma banishes from consideration the interactions among the numerous molecular processes that have been discovered in cells or in their extracted fluids. In the living cell, molecular processes – the synthesis of nucleic acids and proteins or the oxidation of food substance – are not separate but interact in exceedingly complex ways. No matter how many ingredients the biochemists’ test tubes may contain, the mixtures are nonliving. However, these same ingredients, organized by the subtle structure of the cell, constitute a system, which is alive.

Consider an example from another field. At ordinary temperatures, electricity flows only so long as a driving force from a battery or generator is imposed upon the circuit. At temperatures near absolute zero, metals exhibit superconductivity: a unique property that causes an electric current to flow for months after the voltage is cut off. Although independent electrons exist in a metal at ordinary temperatures, at very low temperatures they interact with the metal’s atomic structure in such a way as to lose their individual identities and form a coordinated, collective system which gives rise to superconductivity.

Such discoveries of modern physics show that the unique properties of a complex system are not necessarily explicable solely by the properties that can be observed in its isolated parts. We can expect to find a similar situation in the complex chemical system of the living cells.    1 
 1. The author primarily is concerned with:

A) proposing that a new philosophical foundation for modern biochemistry be developed.
B) describing the various processes that take place in a living cell.
C) drawing analogies between different scientific fields.
D) revealing a discrepancy between a scientific theory and some experimental results.
E) questioning the assumptions behind experimental methods in science.

2 
 2. The author provides information that would answer which of the following questions?

I. What have test-tube experiments revealed about the role of DNA?
II. What viruses interfere with DNA replication?
III. What methods have been developed to allow scientists to observe a living cell?

A) I only
B) II only
C) I and III only
D) II and III only
E) I, II and III

3 
 3. The author’s argument is directed against which of the following?

I. the use of test-tube experimentation alone to establish the validity of scientific theories
II. the exclusion of experimental facts from the formation of scientific theories
III. the observation of certain cellular components in isolation

A) I only
B) I and II only
C) I and III only
D) II and III only
E) I, II and III

4 
 4. The author refers to the results of test-tube experiments involving the replication of DNA primarily in order to

A) question the validity of experimental results that describe the structure of DNA.
B) provide evidence to contradict the theory that DNA alone governs protein synthesis.
C) show the way in which DNA acts as a self-duplicating molecule.
D) explain the internal structure of DNA.
E) reveal how nucleic acid can influence the synthesis of proteins.

5 
 5. According to the passage, a metal cannot become super conductive unless:

A) the voltage through the metal is increased.
B) the metal’s atomic structure has been destroyed.
C) the metal is exposed to very low temperatures.
D) electrons in the metal interact with one another at ordinary temperatures.
E) electrical flow is provided by a battery.

6 
 6. The author suggests that the most important difference observed between a dead cell and a living cell results primarily from the

A) differences in the chemical elements present in each.
B) differences in the degree of acidity present in each.
C) biochemical procedures used to examine each cell.
D) varying temperatures at which cells are examined.
E) integrating mechanism thought to exist within the structure of the living cell.

7 
 7. The experimental results mentioned in the passage suggest that biological inheritance depends on:

A) instructions contained in a single molecule within the cell.
B) processes that are guided by specific enzymes.
C) genetic information contained in metallic salts.
D) interactions among several molecular processes in the cell.
E) replicative processes within the chemistry of protein synthesis.

8 
 8. The author presents his argument primarily by:

A) contrasting two fields of science.
B) providing experimental evidence against a point of view.
C) criticizing proponents of other theories.
D) stating a new theory and its important implications.
E) comparing two theories of cellular structure.

Source: 800Score GMAT Free Course

100mitra · Answer

Paraphrasing:   
1. Main View: DNA - cell’s protein-synthesizing machinery, can be a guiding message agent
2. Different views between proponents who support scientific theory and contrast test tube experiments 
 “ Proteins cannot guide the synthesis of nucleic acids ”.
3. Complex chemical system in living cells, with example of another field about electric flow as protein cells agent
4.   Conclusion:   We can expect to find a similar situation in the complex chemical system of the living cells.

1. The author primarily is concerned with:  
  Correct option D:
As mentioned in the Para 2: we can infer author main concern.  
 Proponents of scientific theory  “ unproven assumption that, 
1. Nucleic acids can guide the synthesis of other nucleic acids and of proteins – supports 
2. Proteins cannot guide the synthesis of nucleic acids ”
 Contrast to:  
“ But actual experimental observations deny the second and crucial part of this assumption. 
Other test-tube experiments show that agents besides DNA have a guiding influence ”

A.   Wrong –   as there is no new philosophical foundation developed 
B.   Wrong –   No various process discussed in living cells, expect Protein cells behaviour as guiding agent.
C.   Wrong –   No analogies 
E.   Wrong –   No questioning the assumption behind experimental methods

2. The author provides information that would answer which of the following questions?  
  Correct option A  
I. What have test-tube experiments revealed about the role of DNA?
“ Other test-tube experiments show that agents besides DNA have a guiding influence ”

II. What viruses interfere with DNA replication?   Wrong –   , Virus – Out of scope

III. What methods have been developed to allow scientists to observe a living cell?
  Wrong –   Trap! In passage, no methods developed has been discussed only scientific theory is either mentioned or explained such as: molecular processes, discoveries of modern physics, Other test-tube experiments, “central dogma” into scientific literature, and the cellular mechanisms of heredity

3. The author’s argument is directed against which of the following?  
  Correct option E   “  against  ”
As mentioned in the passage, 
“ Such discoveries of modern physics show that the unique properties of a complex system are not necessarily explicable solely by the properties that can be observed in its isolated parts ”
 We can clearly infer, there might be many other ways to validate the scientific theories, or keeping experimental facts away from formation of scientific theories, or observation in isolation .

I. the use of test-tube experimentation alone to establish the validity of scientific theories   – against   
II. the exclusion of experimental facts from the formation of scientific theories   – against   
III. the observation of certain cellular components in isolation   – against

4. The author refers to the results of test-tube experiments 
involving the replication of DNA primarily in order to  
  as mentioned in the passage, 
Correct option B, para 1 - last line 
Provides evidence against heredity establish for inheritance  
“ This idea, when added to what was already known about the cellular mechanisms of heredity 
(Especially the knowledge that DNA is localized in chromosomes), 
appeared to establish a molecular basis for inheritance ”

A) question the validity of experimental results that describe the structure of DNA   – against   
  B) provide evidence to contradict the theory that DNA alone governs protein synthesis - Correct  
C) show the way in which DNA acts as a self-duplicating molecule   – against   
D) explain the internal structure of DNA   – against    
E) reveal how nucleic acid can influence the synthesis of proteins   – against

100mitra · Answer

5. According to the passage, a metal cannot become super conductive unless:  
as mentioned in the passage:
  1. At temperatures near absolute zero, metals exhibit superconductivity, a unique property that causes   
2. an electric current to flow for months after the voltage is cut off (Voltage is zero)
3. The metal’s atomic structure form a coordinated
4. Electrons at very low temperatures they interact with the metal’s atomic

A) the voltage through the metal is increased   – Wrong   - Point 2
B) the metal’s atomic structure has been destroyed   – Wrong   – Point 3
  C) the metal is exposed to very low temperatures Correct – Point 1  
D) electrons in the metal interact with one another at ordinary temperatures   – Wrong   – Point 4
E) electrical flow is provided by a battery   – Wrong   its at ordinary temperature

6. The author suggests that the most important difference observed 
between a dead cell and a living cell results primarily from the:  
  as mentioned in the passage, correct option E
E) integrating mechanism thought to exist within the structure of the living cell
“The central dogma banishes from consideration 
the interactions among the numerous molecular processes 
that have been discovered in cells or in their extracted fluids”

Eliminate, A, B, C and D all are out of scope   
A) differences in the chemical elements present in each
B) differences in the degree of acidity present in each
C) biochemical procedures used to examine each cell 
D) varying temperatures at which cells are examined

7. The experimental results mentioned in the passage suggest that 
biological inheritance depends on:  
 sentence 1:  “containing a code that by itself determined biological inheritance, 
introduced the term “central dogma” into scientific literature”
 Sentence 2:  “The central dogma banishes from consideration the interactions among the numerous molecular processes that have been discovered in cells or in their extracted fluids”

Eliminate, B, C and E – all are not related   
B) processes that are guided by specific enzymes  – Not a process 
C) genetic information contained in metallic salts  – No metallic salts 
E) replicative processes within the chemistry of protein synthesis  – no chemistry of protein synthesis

Between A, and D 
 Sentence 1  use word “biological inheritance” to describe “central dogma” and 
what is “central dogma” is explained in  sentence 2 ,   which makes A wrong and D correct  .

A) instructions contained in a single molecule within the cell   – Wrong, Trap!   
  D) interactions among several molecular processes in the cell – Correct

8. The author presents his argument primarily by:  
 View point:  “ DNA appeared to guide the cell’s protein-synthesizing machinery ”
 Providing experimental evidence:  
“ Experiments indicated that in the presence of appropriate enzymes each DNA molecule could form a replica, 
a new DNA molecule, containing the specific guiding message present in the original. 
This idea, when added to what was already known about the cellular mechanisms of heredity appeared to establish a molecular basis for inheritance. ”

Correct option B) providing experimental evidence against a point of view .

Eliminate, A, C, D and E   
A) contrasting two fields of science  – Single field, two ways of view presented in the passage 
C) criticizing proponents of other theories  – No Criticizing done, evidence provided 
D) stating a new theory and its important implications  – No New theory discussed  
E) comparing two theories of cellular structure  – single cellular structure discussed

Nearly twenty years ago, biochemists found that a separable constituen

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

Nearly twenty years ago, biochemists found that a separable constituen

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