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Light is registered in the retina when photons hit molecules

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Light is registered in the retina when photons hit molecules

by dddanny2006 » Wed Feb 26, 2014 7:31 am
Hey guys..
I need some help on the attached question.

Light is registered in the retina when photons hit molecules of the pigment Rhodopsin and change the molecule shape.Even when they have not been struck by photons of light ,rhodopsin molecules sometimes change shape because of normal molecular motion,thereby introducing error into the visual system.The amount of this molecular motion is directly proportional to the Temperature of the retina

Which one of the following conclusions is most strongly supported by the information above?

A.The temperature of an Animals retina depends on the amount of light the retina is absorbing.

B.The visual systems of animals whose body temperature matches that of their surroundings are more error-prone in hot surroundings than in cold ones.

C.As the temperature of the retina increases ,rhodopsin molecules react more slowly to being struck by photons.

D.Rhodopsin molecules are more sensitive to photons in animals whose retinas have large surface area's than in animals whose retinas have small surface area's.

E.Molecules of Rhodopsin are the only pigment molecules that occur naturally in the retina.


First of all there's nothing about animals in the stimulus.As a result I automatically eliminate A,B and D.We're only left with C and E.However E can be eliminated too as there is nothing that makes Rhodopsin the only pigment.

Thats done.

Secondly even if we consider animals to be part of the stimulus(We're not supposed to,but I agree to disagree).
Option A. Temperature <-->Molecular motion , Now is Amount of light <--->Molecular motion?? We're not told,hence I eliminate A

I'm left with B,C,D, &E

I can eliminate C & E,citing lack of information in the Stimulus.

So I now have B,D.How do I eliminate one among these two choices?First of all I think I've done a great job by eliminating A,C & E.To be honest all answers looked unlikely,however can anyone please clarify this problem?It looks unsolvable.

Also,please tell me more about MOST,SOME,MANY in CR questions,which one's are more stricter when it comes to choosing them as answers(I mean which one needs more tests to be conducted by rechecking their quantities in the Stimulus)?

Thank you

Dan
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by Bill@VeritasPrep » Wed Feb 26, 2014 12:44 pm
Well, I think you can safely infer that animals must be involved since they are the only things that have retinas.

We have a few premises to go on:

1. Light changes the shape of Rhodopsin molecules.
2. Rhodopsin molecules sometimes change shape anyway due to molecular motion, causing visual error.
3. Molecular motion is directly related to retina temperature.

It's the second two that are important. The direct proportion between temperature and motion means that as the temperature increases, motion increases as well. Thus, higher temperatures mean more visual error because of more molecular motion.

A--there is nothing in the stimulus linking light to temperature

B--this works. In hot surroundings, their body temps will be higher, leading to more molecular motion and thus more visual error.

C--there is nothing about how temperatures affect the reactivity of rhodopsin to light

D--nothing about surface area of the retina

E--no mention of other potential pigments
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by dddanny2006 » Wed Feb 26, 2014 12:54 pm
Thanks for that Bill.Im findng it hard with these frequency words around.Can you please help me with a chart for-usually,most,many,often,few,some,generally When can these be interchanged?

I find these a bit hard and when I come down to 2 possible answer choices I make an error.
Bill@VeritasPrep wrote:Well, I think you can safely infer that animals must be involved since they are the only things that have retinas.

We have a few premises to go on:

1. Light changes the shape of Rhodopsin molecules.
2. Rhodopsin molecules sometimes change shape anyway due to molecular motion, causing visual error.
3. Molecular motion is directly related to retina temperature.

It's the second two that are important. The direct proportion between temperature and motion means that as the temperature increases, motion increases as well. Thus, higher temperatures mean more visual error because of more molecular motion.

A--there is nothing in the stimulus linking light to temperature

B--this works. In hot surroundings, their body temps will be higher, leading to more molecular motion and thus more visual error.

C--there is nothing about how temperatures affect the reactivity of rhodopsin to light

D--nothing about surface area of the retina

E--no mention of other potential pigments
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by Bill@VeritasPrep » Wed Feb 26, 2014 1:17 pm
dddanny2006 wrote:Thanks for that Bill.Im findng it hard with these frequency words around.Can you please help me with a chart for-usually,most,many,often,few,some,generally When can these be interchanged?
Usually and generally are fairly interchangeable, I'd say.

Most means a majority.

Few means a small number.

Many and some are the most vague. Some means anywhere from one to all ("some patients had side effects" means "at least one patient had a side effect"), while many can be equally ambiguous, as in "many people prefer Pepsi to Coke." If a million people prefer Pepsi, you could safely call that "many people", even if one billion prefer Coke.
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by dddanny2006 » Wed Feb 26, 2014 1:19 pm
Thanks Bill.Is the Retina problem a 700-800 level problem?Does Many equal to all too?In the Powerscore CR bible,there was a question where generally,and usually were not interchangeable there by making it a wrong answer had I proceeded with the interchange.
Bill@VeritasPrep wrote:
dddanny2006 wrote:Thanks for that Bill.Im findng it hard with these frequency words around.Can you please help me with a chart for-usually,most,many,often,few,some,generally When can these be interchanged?
Usually and generally are fairly interchangeable, I'd say.

Most means a majority.

Few means a small number.

Many and some are the most vague. Some means anywhere from one to all ("some patients had side effects" means "at least one patient had a side effect"), while many can be equally ambiguous, as in "many people prefer Pepsi to Coke." If a million people prefer Pepsi, you could safely call that "many people", even if one billion prefer Coke.
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by Bill@VeritasPrep » Wed Feb 26, 2014 1:29 pm
Can you post that question? I'd be interested in seeing it.

As far as many=all, I guess it can. If all widgets are red, then you could say that many widgets are red and be technically correct. Many is more open-ended, and all is very definite. It can only mean 100%.
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by dddanny2006 » Wed Feb 26, 2014 1:38 pm
Yes,sure

The increasing complexity of scientific inquiry has led to a proliferation of multiauthored technical articles. Reports of clinical trials involving patients from several hospitals are usually coauthored by physicians from each participating hospital. Likewise, physics papers reporting results from experiments using subsystems developed at various laboratories generally have authors from each laboratory.

If all of the statements above are true, which one of the following must be true?

(A) Clinical trials involving patients from several hospitals are never conducted solely by physicians from just one hospital.

(B) Most reports of clinical trials involving patients from several hospitals have multiple authors.

(C) When a technical article has multiple authors, they are usually from different institutions.

(D) Physics papers authored by researchers from multiple laboratories usually report results from experiments using subsystems developed at each laboratory.

(E) Most technical articles are authored solely by the researchers who conducted the experiments these articles report.


Answer Choice C should be right if Generally and Usually were interchangeable,but its not.Here's why-

This is a shell game answer choice.Although the stimulus says there has been a proliferation of multi-authored technical articles,no comment is made about the frequency of multi-authored technical articles.In the next sentence,a frequency -"usually"-is given,but only for multi-authored clinical reports.The test makers give you hard data about the clinical trial reports,and then try to entice you into picking a broader answer involving technical reports.From the stimulus,we also have "physics papers reporting results from experiments using subsystems developed at various laboratories generally have authors from each laboratory".


In this entire stimulus technical articles relate not just to clinical trials(usually) but also physics research article(generally).

PS:Please tell me the if this problem and the above Retina one's are 700_800 level one's.I found these hard.

Thanks Bill


Bill@VeritasPrep wrote:Can you post that question? I'd be interested in seeing it.

As far as many=all, I guess it can. If all widgets are red, then you could say that many widgets are red and be technically correct. Many is more open-ended, and all is very definite. It can only mean 100%.
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by Bill@VeritasPrep » Wed Feb 26, 2014 1:48 pm
Is the OA B?

I don't think the key distinction here is "usually" vs "generally", it's technical articles vs clinical trials and physics papers.

From the first sentence, we learn that there has been an increase in the number of multi-authored technical articles. Clinical trials and physics papers represent subsets of "technical articles", but they might be a very small subset. If 10% of technical articles are clinical trials or physics papers, and most of that 10% has multiple authors, that still doesn't tell us anything about the remaining 90%.

In fact, the explanation seems to equate usually and generally: " frequency -"usually"-is given,but only for multi-authored clinical reports." and "from the stimulus,we also have "physics papers reporting results from experiments using subsystems developed at various laboratories generally have authors from each laboratory". "
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by dddanny2006 » Wed Feb 26, 2014 1:55 pm
Yes youre correct.I didnt get that point.The first sentence talks about multi authored technical articles.And then we have two sentences that tell us about clinical trials and research papers.My understanding of the problem was

Clinical trials ---------- Multi-authored Technical Papers-----------Physics Reasearch


Both are subdivisions of Multi-authored Tech papers .So when we talk about tech articles both clinical research trials and physics research should support the said statement in the same way.



What are the previous two question levels,Bill?700-800?
Bill@VeritasPrep wrote:Is the OA B?

I don't think the key distinction here is "usually" vs "generally", it's technical articles vs clinical trials and physics papers.

From the first sentence, we learn that there has been an increase in the number of multi-authored technical articles. Clinical trials and physics papers represent subsets of "technical articles", but they might be a very small subset. If 10% of technical articles are clinical trials or physics papers, and most of that 10% has multiple authors, that still doesn't tell us anything about the remaining 90%.

In fact, the explanation seems to equate usually and generally: " frequency -"usually"-is given,but only for multi-authored clinical reports." and "from the stimulus,we also have "physics papers reporting results from experiments using subsystems developed at various laboratories generally have authors from each laboratory". "
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