GMAT Changed on April 16th - Read about the latest changes here

It is currently 26 Apr 2018, 23:57

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Caffeine, the stimulant in coffee, has been called “the most widely us

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

3 KUDOS received
Intern
Intern
User avatar
Joined: 12 Aug 2015
Posts: 13
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 19 Nov 2015, 01:45
3
This post received
KUDOS
Got 7 right.

One of the tougher questions on RC.
Top Contributor
Director
Director
avatar
Joined: 05 Nov 2012
Posts: 509
Concentration: Technology, Other
GMAT ToolKit User Premium Member Reviews Badge
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 27 Jun 2016, 06:25
Top Contributor
12 mins all correct.~5 mins for para. :(
_________________

--------------------------------------------------------
Regards :)

2 KUDOS received
Manager
Manager
avatar
Joined: 17 Oct 2015
Posts: 113
Location: India
Concentration: Finance
Schools: ISB '18 (S)
GMAT 1: 690 Q47 V37
GMAT 2: 700 Q44 V41
WE: Corporate Finance (Commercial Banking)
Reviews Badge
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 14 Jul 2016, 03:28
2
This post received
KUDOS
don't know whether caffeine causes neuron firing..my neurons are almost on fire after this RC..
Senior Manager
Senior Manager
User avatar
G
Joined: 19 Oct 2012
Posts: 345
Location: India
Concentration: General Management, Operations
GMAT 1: 660 Q47 V35
GMAT 2: 710 Q50 V38
GPA: 3.81
WE: Information Technology (Computer Software)
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 07 Dec 2016, 13:36
Time 14min 09 seconds; 7/9 :( :'(
_________________

Citius, Altius, Fortius

Manager
Manager
avatar
B
Joined: 02 Nov 2013
Posts: 94
Location: India
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 07 Dec 2016, 22:10
The passage is quite tough with lot of scientific words i.e. Nueron, 3-isobutyl-1-methylxanthine etc.

My answer are
B
E
A
D
B
D
Manager
Manager
User avatar
S
Joined: 20 Sep 2016
Posts: 119
GMAT 1: 680 Q49 V35
GPA: 3.99
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 30 Apr 2017, 04:52
Please add timers to the OP.

How do you approach passage like this one on the first read?
Do you just understand the structure and then move on to the questions or do you try to understand the relationships immediately? I thought I could skim over details but the questions proved me wrong :).
Director
Director
User avatar
P
Joined: 18 Aug 2016
Posts: 631
GMAT ToolKit User Premium Member Reviews Badge
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 25 Jun 2017, 23:12
daagh wrote:
Caffeine, the stimulant in coffee, has been called “the most widely used psychoactive substance on Earth.” Snyder, Daly, and Bruns have recently
proposed that caffeine affects behavior by countering the activity in the human brain of a naturally occurring chemical called adenosine. Adenosine normally depresses neuron firing in many areas of the brain. It apparently does this by inhibiting the release of neurotransmitters,chemicals that carry nerve impulses from one neuron to the next.

Like many other agents that affect neuron firing, adenosine must first bind to specific receptors on neuronal membranes. There are at least two classes of these receptors, which have been designated A1 and A2. Snyder et al. propose that caffeine, which is structurally similar to adenosine, is able to bind to both types of ceptors, which prevents adenosine from attaching there and allows the neurons to fire more readily than they otherwise would.

For many years, caffeine’s effects have been attributed to its inhibition of the production of phosphodiesterase, an enzyme that breaks down the chemical called cyclic AMP. A number of neurotransmitters exert their effects by first increasing cyclic AMP concentrations in target neurons. Therefore, prolonged periods at the elevated concentrations, as might be brought about by a phosphodiesterase inhibitor, could lead to a greater amount of neuron firing and, consequently, to behavioral stimulation. But Snyder et al. point out that the caffeine concentrations needed to inhibit the production of phosphodiesterase in the brain are much higher than those that produce stimulation. Moreover, other compounds that block phosphodiesterase’s activity are not stimulants.

To buttress their case that caffeine acts instead by preventing adenosine binding, Snyder et al. compared the stimulatory effects of a series of caffeine derivatives with their ability to dislodge adenosine from its receptors in the brains of mice. “In general,” they reported, “the ability of the compounds to compete at the receptors correlates with their ability to stimulate locomotion in the mouse; i.e., the higher their capacity to bind at the receptors, the higher their ability to stimulate locomotion.” Theophylline, a close structural relative of caffeine and the major stimulant in tea, was one of the most effective compounds in both regards.

There were some apparent exceptions to the general correlation observed between adenosine receptor binding and stimulation. One of these was a compound called 3-isobutyl-1-methylxanthine (IBMX), which bound very well but actually depressed mouse locomotion. Snyder et al. suggest that this is not a major stumbling block to their hypothesis. The problem is that the compound has mixed effects in the brain, a not unusual occurrence with psychoactive drugs. Even caffeine, which is generally known only for its stimulatory effects, displays this property, depressing mouse locomotion at very low concentrations and stimulating it at higher ones.



71. The primary purpose of the passage is to

(A) discuss a plan for investigation of a phenomenon that is not yet fully understood
(B) present two explanations of a phenomenon and reconcile the differences between them
(C) summarize two theories and suggest a third theory that overcomes the problems encountered in the first two
(D) describe an alternative hypothesis and provide evidence and arguments that support it
(E) challenge the validity of a theory by exposing the inconsistencies and contradictions in it

OA&OE
[Reveal] Spoiler:
71 A The passage discusses a current investigation, not one planned for the future.
B The passage examines two explanations, but the earlier theory is discussed only to expose its weakness and the diff erences between the explanations are not reconciled. Most of the passage is devoted to the more recent hypothesis.
C Only two theories are presented in the passage.
D Correct. Th e recent hypothesis provides an alternative to an earlier one and is supported by evidence and arguments.
E Lines 32–37 do pose such a challenge to the earlier theory; however, the challenge is a small part of the whole passage. Similarly, in the final paragraph, an exception to the more recent theory is introduced, only to be dismissed as an unimportant concern.

The correct answer is D.


72. According to Snyder et al., caffeine differs from adenosine in that caffeine

(A) stimulates behavior in the mouse and in humans,whereas adenosine stimulates behavior in humans only
(B) has mixed effects in the brain, whereas adenosine has only a stimulatory effect
(C) increases cyclic AMP concentrations in target neurons, whereas adenosine decreases such concentrations
(D) permits release of neurotransmitters when it is bound to adenosine receptors, whereas adenosine inhibits such release
(E) inhibits both neuron fi ring and the production of phosphodiesterase when there is a sufficient concentration in the brain, whereas adenosine inhibits only neuron firing

OA&OE
[Reveal] Spoiler:
72. A The passage does not suggest that adenosine stimulates behavior.
B While the fi nal paragraph reveals that caff eine displays mixed eff ects, the passage does not state that adenosine has a stimulatory eff ect.
C Increasing cyclic AMP concentrations is part of the earlier theory, not that of Snyder et al.
D Correct. Lines 17–21 explain that caffeine binds to the receptors, releasing neurotransmitters, whereas adenosine hinders that release.
E Inhibiting the production of phosphodiesterase is discussed in the earlier theory, not in the work of Snyder et al.

The correct answer is D.


73. In response to experimental results concerning IBMX, Snyder et al. contended that it is not uncommon for psychoactive drugs to have

(A) mixed effects in the brain
(B) inhibitory effects on enzymes in the brain
(C) close structural relationships with caffeine
(D) depressive effects on mouse locomotion
(E) the ability to dislodge caffeine from receptors in the brain

OA&OE
[Reveal] Spoiler:
73. A Correct. The results of one experiment can be explained by mixed eff ects in the brain, which Snyder et al. say may occur with psychoactive drugs.
B This response refers back to the earlier theory, not to Snyder et al.’s response concerning IBMX experiment results.
C Caffeine is only included within the broad category of psychoactive drugs.
D This effect is attributed to one compound,IBMX, not to all psychoactive drugs.
E This ability is not discussed in the passage.

The correct answer is A.


74. According to Snyder et al., all of the following
compounds can bind to specifi c receptors in the brain
EXCEPT

(A) IBMX
(B) caffeine
(C) adenosine
(D) theophylline
(E) phosphodiesterase

OA&OE
[Reveal] Spoiler:
74. A Lines 54–55 state that IBMX binds to receptors.
B Lines 17–19 state that caff eine binds to receptors.
C Lines 13–14 state that adenosine binds to receptors.
D Lines 46–50 state that theophylline binds to receptors.
E Correct. Th e passage includes no evidence that phosphodiesterase binds to receptors.

The correct answer is E.


75. Snyder et al. suggest that caffeine’s ability to bind to A1 and A2 receptors can be at least partially attributed to which of the following?

(A) The chemical relationship between caffeine and phosphodiesterase
(B) The structural relationship between caffeine and adenosine
(C) The structural similarity between caffeine and neurotransmitters
(D) The ability of caffeine to stimulate behavior
(E) The natural occurrence of caffeine and adenosine in the brain

OA&OE
[Reveal] Spoiler:
75 A Phosphodiesterase is discussed in an entirely diff erent context in lines 22–25.
B Correct. Lines 17–19 suggest that caffeine’s structural similarity to adenosine may be responsible for its ability to bind to A1 and A2 receptors.

C Caff eine acts on neurotransmitters; it is not structurally similar to them.
D Caffeine’s ability to stimulate behavior results from, rather than causes, this process.
E The passage does not discuss the natural occurrence of these compounds.

The correct answer is B.



76. The author quotes Snyder et al. in lines 43–48 most probably in order to

(A) reveal some of the assumptions underlying their theory
(B) summarize a major fi nding of their experiments
(C) point out that their experiments were limited to the mouse
(D) indicate that their experiments resulted only in general correlations
(E) refute the objections made by supporters of the older theory

OA&OE
[Reveal] Spoiler:
76. A The quotation explains results of an experiment, not assumptions about a theory.
B Correct. The quotation summarizes the experiment with mice and reports a major finding in support of the hypothesis.
C The quotation generalizes on the basis of the experiment; it does not limit the finding to mice.
D Specific, not general, correlations were made between the ability to bind to receptors and to stimulate locomotion.
E The passage includes no such objections; therefore no refutations are needed.

The correct answer is B.



13 minutes 36 Sec

B
D
A
E
D
D
_________________

We must try to achieve the best within us


Thanks
Luckisnoexcuse

Expert Post
GMAT Club Verbal Expert
User avatar
P
Status: GMAT and GRE tutor
Joined: 13 Aug 2009
Posts: 1603
Location: United States
GMAT 1: 780 Q51 V46
GMAT 2: 800 Q51 V51
GRE 1: 340 Q170 V170
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 05 Jul 2017, 21:22
kivalo wrote:
Please add timers to the OP.

How do you approach passage like this one on the first read?
Do you just understand the structure and then move on to the questions or do you try to understand the relationships immediately? I thought I could skim over details but the questions proved me wrong :).

Check out the Ultimate RC Guide for Beginners for tips on how to approach RC passages like this one!
_________________

GMAT Club Verbal Expert | GMAT/GRE tutor @ www.gmatninja.com (Now hiring!) | GMAT blog | Food blog | Notoriously bad at PMs

Beginners' guides to GMAT verbal
Reading Comprehension | Critical Reasoning | Sentence Correction

YouTube LIVE verbal webinars
Series 1: Fundamentals of SC & CR | Series 2: Developing a Winning GMAT Mindset -- Wednesdays, February 14 - April 4!

SC & CR Questions of the Day (QOTDs), featuring expert explanations
All QOTDs | Subscribe via email | RSS

Need an expert reply?
Hit the request verbal experts' reply button -- and please be specific about your question. Feel free to tag @GMATNinja and @GMATNinjaTwo in your post.

Sentence Correction articles & resources
How to go from great (760) to incredible (780) on GMAT SC | That "-ing" Word Probably Isn't a Verb | That "-ed" Word Might Not Be a Verb, Either | No-BS Guide to GMAT Idioms | "Being" is not the enemy | WTF is "that" doing in my sentence?

Reading Comprehension, Critical Reasoning, and other articles & resources
All GMAT Ninja articles on GMAT Club | Using LSAT for GMAT CR & RC |7 reasons why your actual GMAT scores don't match your practice test scores | How to get 4 additional "fake" GMAT Prep tests for $29.99 | Time management on verbal

Intern
Intern
avatar
B
Joined: 25 Apr 2016
Posts: 3
Premium Member
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 12 Jul 2017, 20:55
This passage took me 20 minutes to read. :shock: Here is my understanding of the passage.

#1. S.D.B. came up with a hypothesis that caffeine affects behavior by doing the opposite of what adenosine (ade) does.

#2. S.D.B. further explain how that works. Because caffeine is structurally similar to ade, it can prevent ade from attaching A1&A2 and allows more neuron firing.

#3. S.D.B. refute the previous view that caffeine affects behavior by stop producing phosphodiesterase(pho). It will need more caffeine concentrations to do that.

#4. S.D.B. strengthen their hypothesis by citing an experiment. They conclude that the higher the compounds’ capacity to bind at the receptors, the higher the compounds’ ability to stimulate behavior. (Theophylline <Theo> is such a compound.)

#5. S.D.B. argue that although there are some compounds don’t show that kind of correlation mentioned in #4, their hypothesis is still valid.
Current Student
avatar
S
Joined: 31 Dec 2015
Posts: 60
Location: India
GMAT 1: 670 Q44 V38
GMAT 2: 680 Q44 V39
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 14 Jul 2017, 08:45
I really don't understand the point of doing this RC when the answers are right below the questions in plain sight.

Not posting the questions in the correct format spoils the experience of actually finding the answers to the questions from the passage!
Intern
Intern
avatar
B
Joined: 19 Sep 2011
Posts: 28
GMAT ToolKit User Premium Member
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 17 Jul 2017, 19:56
It took me 17 minutes to read and answer 6 questions.
I got 5 correct. Can an expert throw some light on whether the time taken justifies the complexity of this passage? Should it be less??
VP
VP
User avatar
D
Joined: 28 Mar 2017
Posts: 1002
Location: India
Concentration: Finance, Technology
GMAT 1: 730 Q49 V41
GPA: 4
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 19 Dec 2017, 10:22
2 KUDOS received
Manager
Manager
User avatar
B
Joined: 03 May 2017
Posts: 109
GMAT ToolKit User
Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 19 Dec 2017, 17:38
2
This post received
KUDOS
gmatexam439 wrote:
Hi,

Please can you throw some light on question 8!

Regards


The passage suggests that Snyder et al believe that if the older theory concerning caffeine’s effects were correct, which of the following would have to be the case?

I. All neurotransmitters would increase the short-term concentration of cyclic AMP in target neurons.

II. Substances other than caffeine that inhibit the production of phosphodiesterase would be stimulants.

III. All concentration levels of caffeine that are high enough to produce stimulation would also inhibit the production of phosphodiesterase.

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

This is the concerned paragraph

"For many years, caffeine’s effects have been attributed to its inhibition of the production of phosphodiesterase, an enzyme that breaks down the chemical called cyclic AMP. A number of neurotransmitters exert their effects by first increasing cyclic AMP concentrations in target neurons. Therefore, prolonged periods at the elevated concentrations, as might be brought about by a phosphodiesterase inhibitor, could lead to a greater amount of neuron firing and, consequently, to behavioral stimulation. But Snyder et al. point out that the caffeine concentrations needed to inhibit the production of phosphodiesterase in the brain are much higher than those that produce stimulation. Moreover, other compounds that block phosphodiesterase’s activity are not stimulants."

So this paragraph is saying 2 distinct things and we are looking for scenarios that will question the Snyder team's conclusion.

1. Yes, caffeine may inhibit the production of phosphodiesterase which in turn leads to stimulation, however, stimulation will occur before you get to the level required for the aforementioned inhibition.

This is negated by III - All concentration levels of caffeine that are high enough to produce stimulation would also inhibit the production of phosphodiesterase.


2. Compounds can impede the activity of phosphodiesterase without being stimulants.

This is negated by II - Substances other than caffeine that inhibits the production of phosphodiesterase would be stimulants.

Hence, II & III are would be true if the old theory were true. Hence D.

Statement I - "All neurotransmitters would increase the short-term concentration of cyclic AMP in target neurons" is simply irrelevant to the question and out of scope we are concerned with the path that caffeine and other compounds take to effect stimulation and whether the inhibition of an enzyme is that path. The role of neurotransmitter is simply intermediate and would occur regardless.

I hope this helps.
Expert Post
GMAT Club Verbal Expert
User avatar
S
Joined: 20 Nov 2016
Posts: 267
CAT Tests
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 19 Dec 2017, 18:38
gmatexam439 wrote:
Hi,

Please can you throw some light on question 8!

Regards

Thanks rulingbear for the explanation! Also, questions 7-9 don't appear to be official questions. It is possible that they appeared in the 10th edition (and if somebody has a copy, please take a look!), but the 2015 and 2016 Verbal Reviews only contain the first 6 questions for this passage.
_________________

www.gmatninja.com

1 KUDOS received
Intern
Intern
avatar
S
Joined: 18 Jan 2017
Posts: 49
Location: India
Concentration: General Management, Entrepreneurship
GPA: 4
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 20 Dec 2017, 06:10
1
This post received
KUDOS
took me 15 minutes to solve this!
had to read it twice!
q7 and q8 took 2 mins each!

Got 1 wrong! question 7!

Is it super hard or is it just me?
1 KUDOS received
VP
VP
User avatar
D
Joined: 28 Mar 2017
Posts: 1002
Location: India
Concentration: Finance, Technology
GMAT 1: 730 Q49 V41
GPA: 4
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 20 Dec 2017, 09:00
1
This post received
KUDOS
GMATNinjaTwo wrote:
gmatexam439 wrote:
Hi,

Please can you throw some light on question 8!

Regards

Thanks rulingbear for the explanation! Also, questions 7-9 don't appear to be official questions. It is possible that they appeared in the 10th edition (and if somebody has a copy, please take a look!), but the 2015 and 2016 Verbal Reviews only contain the first 6 questions for this passage.


Hello GMATNinjaTwo,

In OG10 also there are 6 questions only: 7,8 and 9 aren't official.
Do you suggest to take some time and review 7 and 8. I got both wrong. 8 one especially isn't making much sense to me.

Regards
_________________

Kudos if my post helps!

Long And A Fruitful Journey - V21 to V41; If I can, So Can You!!


My study resources:
1. Useful Formulae, Concepts and Tricks-Quant
2. e-GMAT's ALL SC Compilation
3. LSAT RC compilation
4. Actual LSAT CR collection by Broal
5. QOTD RC (Carcass)
6. Challange OG RC
7. GMAT Prep Challenge RC

VP
VP
User avatar
D
Joined: 28 Mar 2017
Posts: 1002
Location: India
Concentration: Finance, Technology
GMAT 1: 730 Q49 V41
GPA: 4
Re: Caffeine, the stimulant in coffee, has been called “the most widely us [#permalink]

Show Tags

New post 20 Dec 2017, 09:04
rulingbear wrote:
gmatexam439 wrote:
Hi,

Please can you throw some light on question 8!

Regards


The passage suggests that Snyder et al believe that if the older theory concerning caffeine’s effects were correct, which of the following would have to be the case?

I. All neurotransmitters would increase the short-term concentration of cyclic AMP in target neurons.

II. Substances other than caffeine that inhibit the production of phosphodiesterase would be stimulants.

III. All concentration levels of caffeine that are high enough to produce stimulation would also inhibit the production of phosphodiesterase.

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

This is the concerned paragraph

"For many years, caffeine’s effects have been attributed to its inhibition of the production of phosphodiesterase, an enzyme that breaks down the chemical called cyclic AMP. A number of neurotransmitters exert their effects by first increasing cyclic AMP concentrations in target neurons. Therefore, prolonged periods at the elevated concentrations, as might be brought about by a phosphodiesterase inhibitor, could lead to a greater amount of neuron firing and, consequently, to behavioral stimulation. But Snyder et al. point out that the caffeine concentrations needed to inhibit the production of phosphodiesterase in the brain are much higher than those that produce stimulation. Moreover, other compounds that block phosphodiesterase’s activity are not stimulants."

So this paragraph is saying 2 distinct things and we are looking for scenarios that will question the Snyder team's conclusion.

1. Yes, caffeine may inhibit the production of phosphodiesterase which in turn leads to stimulation, however, stimulation will occur before you get to the level required for the aforementioned inhibition.

This is negated by III - All concentration levels of caffeine that are high enough to produce stimulation would also inhibit the production of phosphodiesterase.


2. Compounds can impede the activity of phosphodiesterase without being stimulants.

This is negated by II - Substances other than caffeine that inhibits the production of phosphodiesterase would be stimulants.

Hence, II & III are would be true if the old theory were true. Hence D.

Statement I - "All neurotransmitters would increase the short-term concentration of cyclic AMP in target neurons" is simply irrelevant to the question and out of scope we are concerned with the path that caffeine and other compounds take to effect stimulation and whether the inhibition of an enzyme is that path. The role of neurotransmitter is simply intermediate and would occur regardless.

I hope this helps.


I see, so the question is just double negation !! Makes a lot of sense now. Thanks ... +1 given :)
_________________

Kudos if my post helps!

Long And A Fruitful Journey - V21 to V41; If I can, So Can You!!


My study resources:
1. Useful Formulae, Concepts and Tricks-Quant
2. e-GMAT's ALL SC Compilation
3. LSAT RC compilation
4. Actual LSAT CR collection by Broal
5. QOTD RC (Carcass)
6. Challange OG RC
7. GMAT Prep Challenge RC

Re: Caffeine, the stimulant in coffee, has been called “the most widely us   [#permalink] 20 Dec 2017, 09:04

Go to page   Previous    1   2   [ 37 posts ] 

Display posts from previous: Sort by

Caffeine, the stimulant in coffee, has been called “the most widely us

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.