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28 Jul 2021, 06:00
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Question 1
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
55%
(hard)
Question Stats:
61% (03:26) correct
39%
(03:28) wrong
based on 393
sessions
History
Date
Time
Result
Not Attempted Yet
Question 2
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
5%
(low)
Question Stats:
92% (00:38) correct 8%
(01:04) wrong
based on 541
sessions
History
Date
Time
Result
Not Attempted Yet
Question 3
E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
5%
(low)
Question Stats:
90% (00:53) correct 10%
(01:13) wrong
based on 537
sessions
History
Date
Time
Result
Not Attempted Yet
Question 4
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
55%
(hard)
Question Stats:
53% (01:14) correct 47%
(01:33) wrong
based on 550
sessions
History
Date
Time
Result
Not Attempted Yet
Question 5
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
35%
(medium)
Question Stats:
67% (01:27) correct 33%
(01:28) wrong
based on 500
sessions
History
Date
Time
Result
Not Attempted Yet
Question 6
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
55%
(hard)
Question Stats:
45% (00:54) correct 55%
(00:54) wrong
based on 500
sessions
History
Date
Time
Result
Not Attempted Yet
Neurobiologists once believed that the workings of
the brain were guided exclusively by electrical signals;
according to this theory, communication between
neurons (brain cells) is possible because electrical
(5) impulses travel from one neuron to the next by literally
leaping across the synapses (gaps between neurons).
But many neurobiologists puzzled over how this
leaping across synapses might be achieved, and as
early as 1904 some speculated that electrical impulses
(10) are transmitted between neurons chemically rather
than electrically. According to this alternative theory, the
excited neuron secretes a chemical called a
neurotransmitter that binds with its corresponding
receptor molecule in the receiving neuron. This binding
(15) of the neurotransmitter renders the neuron permeable
to ions, and as the ions move into the receiving neuron
they generate an electrical impulse that runs through
the cell; the electrical impulse is thereby transmitted to
the receiving neuron.
(20) This theory has gradually won acceptance in the
scientific community, but for a long time little was
known about the mechanism by which
neurotransmitters manage to render the receiving
neuron permeable to ions. In fact, some scientists
(25) remained skeptical of the theory because they had
trouble imagining how the binding of a chemical to a
receptor at the cell surface could influence the flow of
ions through the cell membrane. Recently, however,
researchers have gathered enough evidence for a
(30)convincing explanation: that the structure of receptors
plays the pivotal role in mediating the conversion of
chemical signals into electrical activity.
The new evidence shows that receptors for
neurotransmitters contain both a neurotransmitter
(35) binding site and a separate region that functions as a
channel for ions; attachment of the neurotransmitter to
the binding site causes the receptor to change shape
and so results in the opening of its channel component.
Several types of receptors have been isolated that
(40) conform to this structure, among them the receptors
for acetylcholine, gamma-aminobutyric acid (GABA),
glycine, and serotonin. These receptors display enough
similarities to constitute a family, known collectively
as neurotransmitter-gated ion channels.
(45) It has also been discovered that each of the
receptors in this family comes in several varieties so
that, for example, a GABA receptor in one part of the
brain has slightly different properties than a GABA
receptor in another part of the brain. This discovery is
(50) medically significant because it raises the possibility of
the highly selective treatment of certain brain
disorders. As the precise effect on behavior of every
variety of each neurotransmitter-gated ion channel is
deciphered, pharmacologists may be able to design
(55) drugs targeted to specific receptors on defined
categories of neurons that will selectively impede or
enhance these effects. Such drugs could potentially
help ameliorate any number of debilitating conditions,
including mood disorders, tissue damage associated
(60) with stroke, or Alzheimer’s disease.
the brain were guided exclusively by electrical signals;
according to this theory, communication between
neurons (brain cells) is possible because electrical
(5) impulses travel from one neuron to the next by literally
leaping across the synapses (gaps between neurons).
But many neurobiologists puzzled over how this
leaping across synapses might be achieved, and as
early as 1904 some speculated that electrical impulses
(10) are transmitted between neurons chemically rather
than electrically. According to this alternative theory, the
excited neuron secretes a chemical called a
neurotransmitter that binds with its corresponding
receptor molecule in the receiving neuron. This binding
(15) of the neurotransmitter renders the neuron permeable
to ions, and as the ions move into the receiving neuron
they generate an electrical impulse that runs through
the cell; the electrical impulse is thereby transmitted to
the receiving neuron.
(20) This theory has gradually won acceptance in the
scientific community, but for a long time little was
known about the mechanism by which
neurotransmitters manage to render the receiving
neuron permeable to ions. In fact, some scientists
(25) remained skeptical of the theory because they had
trouble imagining how the binding of a chemical to a
receptor at the cell surface could influence the flow of
ions through the cell membrane. Recently, however,
researchers have gathered enough evidence for a
(30)convincing explanation: that the structure of receptors
plays the pivotal role in mediating the conversion of
chemical signals into electrical activity.
The new evidence shows that receptors for
neurotransmitters contain both a neurotransmitter
(35) binding site and a separate region that functions as a
channel for ions; attachment of the neurotransmitter to
the binding site causes the receptor to change shape
and so results in the opening of its channel component.
Several types of receptors have been isolated that
(40) conform to this structure, among them the receptors
for acetylcholine, gamma-aminobutyric acid (GABA),
glycine, and serotonin. These receptors display enough
similarities to constitute a family, known collectively
as neurotransmitter-gated ion channels.
(45) It has also been discovered that each of the
receptors in this family comes in several varieties so
that, for example, a GABA receptor in one part of the
brain has slightly different properties than a GABA
receptor in another part of the brain. This discovery is
(50) medically significant because it raises the possibility of
the highly selective treatment of certain brain
disorders. As the precise effect on behavior of every
variety of each neurotransmitter-gated ion channel is
deciphered, pharmacologists may be able to design
(55) drugs targeted to specific receptors on defined
categories of neurons that will selectively impede or
enhance these effects. Such drugs could potentially
help ameliorate any number of debilitating conditions,
including mood disorders, tissue damage associated
(60) with stroke, or Alzheimer’s disease.
1. Which one of the following most completely and accurately states the main point of the passage?
(A) Evidence shows that the workings of the brain are guided, not by electrical signals, but by chemicals, and that subtle differences among the receptors for these chemicals may permit the selective treatment of certain brain disorders.
(B) Evidence shows that the workings of the brain are guided, not by electrical signals, but by chemicals, and that enough similarities exist among these chemicals to allow scientists to classify them as a family.
(C) Evidence shows that electrical impulses are transmitted between neurons chemically rather than electrically, and that enough similarities exist among these chemicals to allow scientists to classify them as a family.
(D) Evidence shows that electrical impulses are transmitted between neurons chemically rather than electrically, and that subtle differences among the receptors for these chemicals may permit the selective treatment of certain brain disorders.
(E) Evidence shows that receptor molecules in the brain differ subtly from one another, and that these differences can be exploited to treat certain brain disorders through the use of drugs that selectively affect particular parts of the brain.
(A) Evidence shows that the workings of the brain are guided, not by electrical signals, but by chemicals, and that subtle differences among the receptors for these chemicals may permit the selective treatment of certain brain disorders.
(B) Evidence shows that the workings of the brain are guided, not by electrical signals, but by chemicals, and that enough similarities exist among these chemicals to allow scientists to classify them as a family.
(C) Evidence shows that electrical impulses are transmitted between neurons chemically rather than electrically, and that enough similarities exist among these chemicals to allow scientists to classify them as a family.
(D) Evidence shows that electrical impulses are transmitted between neurons chemically rather than electrically, and that subtle differences among the receptors for these chemicals may permit the selective treatment of certain brain disorders.
(E) Evidence shows that receptor molecules in the brain differ subtly from one another, and that these differences can be exploited to treat certain brain disorders through the use of drugs that selectively affect particular parts of the brain.
2. Based on the passage, the author’s attitude toward the discovery presented in the last paragraph is most accurately described as
(A) certainty that its possible benefits will be realized
(B) optimism about its potential applications
(C) apprehension about the possibility of its misuse
(D) concern that its benefits are easily exaggerated
(E) skepticism toward its assumptions about the brain
(A) certainty that its possible benefits will be realized
(B) optimism about its potential applications
(C) apprehension about the possibility of its misuse
(D) concern that its benefits are easily exaggerated
(E) skepticism toward its assumptions about the brain
3. Each of the following statements is affirmed by the passage EXCEPT:
(A) The secretion of certain chemicals plays a role in neuron communication.
(B) The flow of ions through neurons plays a role in neuron communication.
(C) The binding of neurotransmitters to receptors plays a role in neuron communication.
(D) The structure of receptors on neuron surfaces plays a role in neuron communication.
(E) The size of neurotransmitter binding sites on receptors plays a role in neuron communication.
(A) The secretion of certain chemicals plays a role in neuron communication.
(B) The flow of ions through neurons plays a role in neuron communication.
(C) The binding of neurotransmitters to receptors plays a role in neuron communication.
(D) The structure of receptors on neuron surfaces plays a role in neuron communication.
(E) The size of neurotransmitter binding sites on receptors plays a role in neuron communication.
4. The author most likely uses the phrase “defined categories of neurons” in lines 55–56 in order to refer to neurons that
(A) possess channels for ions
(B) respond to drug treatment
(C) contain receptor molecules
(D) influence particular brain functions
(E) react to binding by neurotransmitters
(A) possess channels for ions
(B) respond to drug treatment
(C) contain receptor molecules
(D) influence particular brain functions
(E) react to binding by neurotransmitters
5. Which one of the following most accurately describes the organization of the passage?
(A) explanation of a theory; presentation of evidence in support of the theory; presentation of evidence in opposition to the theory; argument in favor of rejecting the theory; discussion of the implications of rejecting the theory
(B) explanation of a theory; presentation of evidence in support of the theory; explanation of an alternative theory; presentation of information to support the alternative theory; discussion of an experiment that can help determine which theory is correct
(C) explanation of a theory; description of an obstacle to the theory’s general acceptance; presentation of an explanation that helps the theory overcome the obstacle; discussion of a further implication of the theory
(D) explanation of a theory; description of an obstacle to the theory’s general acceptance; argument that the obstacle is insurmountable and that the theory should be rejected; discussion of the implications of rejecting the theory
(E) explanation of a theory; description of how the theory came to win scientific acceptance; presentation of new information that challenges the theory; modification of the theory to accommodate the new information; discussion of an implication of the modification
(A) explanation of a theory; presentation of evidence in support of the theory; presentation of evidence in opposition to the theory; argument in favor of rejecting the theory; discussion of the implications of rejecting the theory
(B) explanation of a theory; presentation of evidence in support of the theory; explanation of an alternative theory; presentation of information to support the alternative theory; discussion of an experiment that can help determine which theory is correct
(C) explanation of a theory; description of an obstacle to the theory’s general acceptance; presentation of an explanation that helps the theory overcome the obstacle; discussion of a further implication of the theory
(D) explanation of a theory; description of an obstacle to the theory’s general acceptance; argument that the obstacle is insurmountable and that the theory should be rejected; discussion of the implications of rejecting the theory
(E) explanation of a theory; description of how the theory came to win scientific acceptance; presentation of new information that challenges the theory; modification of the theory to accommodate the new information; discussion of an implication of the modification
6. The primary purpose of the passage is most likely to
(A) propose a new theory about the workings of the brain
(B) introduce evidence that challenges a widely accepted theory about the workings of the brain
(C) describe the approach scientists use when studying the workings of the brain
(D) discuss new support for a widely accepted theory about the workings of the brain
(E) illustrate the practical utility of scientific research into the workings of the brain
(A) propose a new theory about the workings of the brain
(B) introduce evidence that challenges a widely accepted theory about the workings of the brain
(C) describe the approach scientists use when studying the workings of the brain
(D) discuss new support for a widely accepted theory about the workings of the brain
(E) illustrate the practical utility of scientific research into the workings of the brain
29 Jul 2021, 07:22
Kudos
Bookmarks
Passage Summary:
P1: (Before) brain guided by electrical sig
(Alt) chemical
P2: Alt won acceptance but scientists wonder about mechanism
Now there comes convincing explanation about structure of receptor
P3: Mechanism
P4: Implication -> drug
Q1 Main point (A vs D)
(A) Evidence shows that the workings of the brain are guided, not by electrical signals, but by chemicals, and that subtle differences among the receptors for these chemicals may permit the selective treatment of certain brain disorders.
(D) Evidence shows that electrical impulses are transmitted between neurons chemically rather than electrically, and that subtle differences among the receptors for these chemicals may permit the selective treatment of certain brain disorders.
The latter part is the same, but the former part of D is more precise.
Q2 Attitude = medically significant
(A) certainty that its possible benefits will be realized (pos but notice maybe)
(B) optimism about its potential applications (pos - ans)
(C) apprehension about the possibility of its misuse (neg)
(D) concern that its benefits are easily exaggerated (neg)
(E) skepticism toward its assumptions about the brain (neg)
Q3 supported EXCEPT
(A) The secretion of certain chemicals plays a role in neuron communication.
(B) The flow of ions through neurons plays a role in neuron communication.
(C) The binding of neurotransmitters to receptors plays a role in neuron communication.
(D) The structure of receptors on neuron surfaces plays a role in neuron communication. (Ans = opposite)
(E) The size of neurotransmitter binding sites on receptors plays a role in neuron communication.
Q4 defined categories of neurons = neurons that impede or enhance effects (=brain disorder)
(A) possess channels for ions
(B) respond to drug treatment
(C) contain receptor molecules
(D) influence particular brain functions (Ans)
(E) react to binding by neurotransmitters
Q5 organization
(A) explanation of a theory; presentation of evidence in support of the theory; presentation of evidence in opposition to the theory; argument in favor of rejecting the theory; discussion of the implications of rejecting the theory (no evidence supporting former -> WRONG)
(B) explanation of a theory; presentation of evidence in support of the theory; explanation of an alternative theory; presentation of information to support the alternative theory; discussion of an experiment that can help determine which theory is correct (same as A -> WRONG)
(C) explanation of a theory; description of an obstacle to the theory’s general acceptance; presentation of an explanation that helps the theory overcome the obstacle; discussion of a further implication of the theory (YES -> ANS)
(D) explanation of a theory; description of an obstacle to the theory’s general acceptance; argument that the obstacle is insurmountable and that the theory should be rejected; discussion of the implications of rejecting the theory (insurmountable -> WRONG)
(E) explanation of a theory; description of how the theory came to win scientific acceptance; presentation of new information that challenges the theory; modification of the theory to accommodate the new information; discussion of an implication of the modification (even if theory stated is alt then presentation of new info that challenges theory is WRONG)
Q6 Purpose (Notice widely accepted = alternative!)
(A) propose a new theory about the workings of the brain (the author does not propose by himself! he just present the new one)
(B) introduce evidence that challenges a widely accepted theory about the workings of the brain (No given that it is alternative)
(C) describe the approach scientists use when studying the workings of the brain (No - only explanation, not approach)
(D) discuss new support for a widely accepted theory about the workings of the brain (YES - convincing explanation to alt)
(E) illustrate the practical utility of scientific research into the workings of the brain (No - only in last P)
P1: (Before) brain guided by electrical sig
(Alt) chemical
P2: Alt won acceptance but scientists wonder about mechanism
Now there comes convincing explanation about structure of receptor
P3: Mechanism
P4: Implication -> drug
Q1 Main point (A vs D)
(A) Evidence shows that the workings of the brain are guided, not by electrical signals, but by chemicals, and that subtle differences among the receptors for these chemicals may permit the selective treatment of certain brain disorders.
(D) Evidence shows that electrical impulses are transmitted between neurons chemically rather than electrically, and that subtle differences among the receptors for these chemicals may permit the selective treatment of certain brain disorders.
The latter part is the same, but the former part of D is more precise.
Q2 Attitude = medically significant
(A) certainty that its possible benefits will be realized (pos but notice maybe)
(B) optimism about its potential applications (pos - ans)
(C) apprehension about the possibility of its misuse (neg)
(D) concern that its benefits are easily exaggerated (neg)
(E) skepticism toward its assumptions about the brain (neg)
Q3 supported EXCEPT
(A) The secretion of certain chemicals plays a role in neuron communication.
(B) The flow of ions through neurons plays a role in neuron communication.
(C) The binding of neurotransmitters to receptors plays a role in neuron communication.
(D) The structure of receptors on neuron surfaces plays a role in neuron communication. (Ans = opposite)
(E) The size of neurotransmitter binding sites on receptors plays a role in neuron communication.
Q4 defined categories of neurons = neurons that impede or enhance effects (=brain disorder)
(A) possess channels for ions
(B) respond to drug treatment
(C) contain receptor molecules
(D) influence particular brain functions (Ans)
(E) react to binding by neurotransmitters
Q5 organization
(A) explanation of a theory; presentation of evidence in support of the theory; presentation of evidence in opposition to the theory; argument in favor of rejecting the theory; discussion of the implications of rejecting the theory (no evidence supporting former -> WRONG)
(B) explanation of a theory; presentation of evidence in support of the theory; explanation of an alternative theory; presentation of information to support the alternative theory; discussion of an experiment that can help determine which theory is correct (same as A -> WRONG)
(C) explanation of a theory; description of an obstacle to the theory’s general acceptance; presentation of an explanation that helps the theory overcome the obstacle; discussion of a further implication of the theory (YES -> ANS)
(D) explanation of a theory; description of an obstacle to the theory’s general acceptance; argument that the obstacle is insurmountable and that the theory should be rejected; discussion of the implications of rejecting the theory (insurmountable -> WRONG)
(E) explanation of a theory; description of how the theory came to win scientific acceptance; presentation of new information that challenges the theory; modification of the theory to accommodate the new information; discussion of an implication of the modification (even if theory stated is alt then presentation of new info that challenges theory is WRONG)
Q6 Purpose (Notice widely accepted = alternative!)
(A) propose a new theory about the workings of the brain (the author does not propose by himself! he just present the new one)
(B) introduce evidence that challenges a widely accepted theory about the workings of the brain (No given that it is alternative)
(C) describe the approach scientists use when studying the workings of the brain (No - only explanation, not approach)
(D) discuss new support for a widely accepted theory about the workings of the brain (YES - convincing explanation to alt)
(E) illustrate the practical utility of scientific research into the workings of the brain (No - only in last P)
16 Nov 2021, 00:14
Kudos
Bookmarks
Sajjad1994, could you please help to explain why B should be eliminated for q4?
According to the last par, Different categories of neurons have specific receptors--> drugs are designed to target these receptors. Drugs should be designed in such a way, so they can stimulate responses from these receptors. Therefore, I picked B. What is wrong with my analysis? What may be missing in my understanding, so I have not selected D?
design
(55) drugs targeted to specific receptors on defined
categories of neurons that will selectively impede or
enhance these effects.
According to the last par, Different categories of neurons have specific receptors--> drugs are designed to target these receptors. Drugs should be designed in such a way, so they can stimulate responses from these receptors. Therefore, I picked B. What is wrong with my analysis? What may be missing in my understanding, so I have not selected D?
design
(55) drugs targeted to specific receptors on defined
categories of neurons that will selectively impede or
enhance these effects.
16 Nov 2021, 08:54
Kudos
Bookmarks
tkorzhan1995
Look (B) carefully, the issue is not whether or not a receptor responds to drugs per se, but which receptor does so in order to have an effect on one brain disorder or another. So (B) is out.
