<section><h2><div class="packagename">Try Out TOEFL iBT</div></h2><p><h1 class="titleea">Try Out TOEFL iBT.</h1><div class="category"><p>TOEFL iBT Program</p></div><div class="t-flex test-time"><img src="https://cdn-web-2.ruangguru.com/landing-pages/assets/hs/English%20Academy/time-icon.svg" /><p id="border-text">90 Minutes </p><img src="https://cdn-web-2.ruangguru.com/landing-pages/assets/hs/English%20Academy/clip-icon.svg" /><p>55 Questions</p></div><br /><h3>Test Sections</h3><ul><li><strong>Reading:</strong> Read the passages and answer the questions</li><li><strong>Listening:</strong> Listen to the lectures and answer the questions</li></ul><h3>During the Test</h3><ul><li>Read and listen to the passages carefully</li><li>Some questions are more difficult than others — try to answer all with your best</li><li>Never leave your any question unanswered</li><li>Try to answer all questions within the time limit</li></ul><p> </p><p>Click “Continue” to start the test.</p><p dir="ltr"> </p></p></section><section><h2><span style="font-size:1.5em;"></span>It can be inferred from paragraph 1 that ornithologists<span style="font-size:1.5em;"></span></h2><p><p dir="ltr"><strong><span style="font-size:16px;">READING 1</span></strong></p><p dir="ltr">Bird Vocalization</p><p dir="ltr">(1) Bird songs are the subject of intense interest among birders and ornithologists around the world, and the beauty and variety of these vocalizations has inspired poets, playwrights and composers alike for centuries. To the untrained ear, differentiating among the thousands of songs and calls that birds create may seem nearly impossible to do. Often times, this massive variation can even exist within one single species. However, just as it is <strong>conceivable</strong> to tell the difference between national and even regional accents in people, so have scientists been able to create an overwhelming catalogue of ornithological vocalizations.</p><p dir="ltr">(2) The basis of a bird’s ability to produce its songs and calls can be found in its anatomy. Unlike the human larynx, which houses the vocal folds, or vocal cords, birds create sounds with two hollow bony structures at the bottom of the trachea called syringes. The fact that each syrinx is located at the bottom of the trachea, where it forks off into the lungs, means that each bronchiole can be used to pass air through the voice boxes, or syringes. These can be controlled independently,</p><p dir="ltr">which explains why some species are capable of making two sounds at once. The syringes vibrate during exhalation, and depending on the tension exerted on them by surrounding muscles, will produce sounds of a different pitch. On the other hand, the volume of any particular sound is determined by the force of the air being exhaled.</p><p dir="ltr">(3) Bird vocalizations can be divided into two general categories: songs and calls. Songs are typically the most intricate type of vocalization in a bird's repertoire and can vary in length and complexity depending on the species. In the majority of cases, they are sung by the male of the species with the intent of establishing and defending a territory or attracting a mate. In contrast, calls, which are usually short bursts of sound characterized by one or a short series of emphatic notes, are used for a variety of purposes: contact and flight calls allow birds to remain in contact with their flock or mates, whereas threat and alarm calls are aggressive in nature and are used to defend territory or warn of a predator respectively. Finally, there are feeding calls, which may be given by either a male or a female while feeding young chicks, and begging calls, given by nestlings or fledglings when they are hungry. </p><p dir="ltr">(4) Not all birds learn to vocalize in the same way. Some species possess inherited abilities, and thus do not need to be taught how to sing their song because they know it intuitively. An experiment was conducted on <strong>the Alder Flycatcher and Willow Flycatcher</strong>, in which young birds were taken from their nests at the age of 10 days. Scientists endeavored to teach each of the young birds the song of the other species involved in the experiment to see if they indeed had an innate knowledge of their own species song. <strong>As it turned out, in spite of the birds being taken out of their environments and surrounded by songs from another species, whose song sounds confusingly similar to their own, the nestlings developed normally and did not mistake their song with that of any other species.</strong></p><br />(5) On the other hand, many other species of bird have to learn their song from an adult "tutor," usually their father. <strong>11A</strong> Without the presence of adults of their own species to imitate, these birds will not develop the ability to sing properly. Some species have a different approach and learn a basic song from their parents and later add to it with improvised melodies that become more layered and complex over time, sometimes to the point that their songs become a separate dialect. <strong>11B</strong> Finally, there are some birds, like the Mockingbird, that have the ability to imitate the songs of other species. <strong>11C</strong> Male Mockingbirds with a wide range of songs in their repertoire are more likely to be older (since it takes time to learn many songs), and this is an attractive trait to female Mockingbirds; older males usually have a larger territory food) and are more experienced, both characteristics of a good father, and therefore highly desirable to the female of the species. <strong>11D</strong></p></section><section><h3><p>Which of the words below could best be replaced by conceivable in paragraph 1?</p></h3><p><p dir="ltr"><strong>READING 1</strong></p><p dir="ltr">Bird Vocalization</p><p dir="ltr">(1) Bird songs are the subject of intense interest among birders and ornithologists around the world, and the beauty and variety of these vocalizations has inspired poets, playwrights and composers alike for centuries. To the untrained ear, differentiating among the thousands of songs and calls that birds create may seem nearly impossible to do. Often times, this massive variation can even exist within one single species. However, just as it is <strong>conceivable</strong> to tell the difference between national and even regional accents in people, so have scientists been able to create an overwhelming catalogue of ornithological vocalizations.</p><p dir="ltr">(2) The basis of a bird’s ability to produce its songs and calls can be found in its anatomy. Unlike the human larynx, which houses the vocal folds, or vocal cords, birds create sounds with two hollow bony structures at the bottom of the trachea called syringes. The fact that each syrinx is located at the bottom of the trachea, where it forks off into the lungs, means that each bronchiole can be used to pass air through the voice boxes, or syringes. These can be controlled independently,</p><p dir="ltr">which explains why some species are capable of making two sounds at once. The syringes vibrate during exhalation, and depending on the tension exerted on them by surrounding muscles, will produce sounds of a different pitch. On the other hand, the volume of any particular sound is determined by the force of the air being exhaled.</p><p dir="ltr">(3) Bird vocalizations can be divided into two general categories: songs and calls. Songs are typically the most intricate type of vocalization in a bird's repertoire and can vary in length and complexity depending on the species. In the majority of cases, they are sung by the male of the species with the intent of establishing and defending a territory or attracting a mate. In contrast, calls, which are usually short bursts of sound characterized by one or a short series of emphatic notes, are used for a variety of purposes: contact and flight calls allow birds to remain in contact with their flock or mates, whereas threat and alarm calls are aggressive in nature and are used to defend territory or warn of a predator respectively. Finally, there are feeding calls, which may be given by either a male or a female while feeding young chicks, and begging calls, given by nestlings or fledglings when they are hungry. </p><p dir="ltr">(4) Not all birds learn to vocalize in the same way. Some species possess inherited abilities, and thus do not need to be taught how to sing their song because they know it intuitively. An experiment was conducted on <strong>the Alder Flycatcher and Willow Flycatcher</strong>, in which young birds were taken from their nests at the age of 10 days. Scientists endeavored to teach each of the young birds the song of the other species involved in the experiment to see if they indeed had an innate knowledge of their own species song. <strong>As it turned out, in spite of the birds being taken out of their environments and surrounded by songs from another species, whose song sounds confusingly similar to their own, the nestlings developed normally and did not mistake their song with that of any other species.</strong></p><br />(5) On the other hand, many other species of bird have to learn their song from an adult "tutor," usually their father. <strong>11A</strong> Without the presence of adults of their own species to imitate, these birds will not develop the ability to sing properly. Some species have a different approach and learn a basic song from their parents and later add to it with improvised melodies that become more layered and complex over time, sometimes to the point that their songs become a separate dialect. <strong>11B</strong> Finally, there are some birds, like the Mockingbird, that have the ability to imitate the songs of other species. <strong>11C</strong> Male Mockingbirds with a wide range of songs in their repertoire are more likely to be older (since it takes time to learn many songs), and this is an attractive trait to female Mockingbirds; older males usually have a larger territory food) and are more experienced, both characteristics of a good father, and therefore highly desirable to the female of the species. <strong>11D</strong></p></section><section><h3><p>According to paragraph 2, what is the source of a bird’s songs and calls?</p></h3><p><p dir="ltr"><strong>READING 1</strong></p><p dir="ltr">Bird Vocalization</p><p dir="ltr">(1) Bird songs are the subject of intense interest among birders and ornithologists around the world, and the beauty and variety of these vocalizations has inspired poets, playwrights and composers alike for centuries. To the untrained ear, differentiating among the thousands of songs and calls that birds create may seem nearly impossible to do. Often times, this massive variation can even exist within one single species. However, just as it is <strong>conceivable</strong> to tell the difference between national and even regional accents in people, so have scientists been able to create an overwhelming catalogue of ornithological vocalizations.</p><p dir="ltr">(2) The basis of a bird’s ability to produce its songs and calls can be found in its anatomy. Unlike the human larynx, which houses the vocal folds, or vocal cords, birds create sounds with two hollow bony structures at the bottom of the trachea called syringes. The fact that each syrinx is located at the bottom of the trachea, where it forks off into the lungs, means that each bronchiole can be used to pass air through the voice boxes, or syringes. These can be controlled independently,</p><p dir="ltr">which explains why some species are capable of making two sounds at once. The syringes vibrate during exhalation, and depending on the tension exerted on them by surrounding muscles, will produce sounds of a different pitch. On the other hand, the volume of any particular sound is determined by the force of the air being exhaled.</p><p dir="ltr">(3) Bird vocalizations can be divided into two general categories: songs and calls. Songs are typically the most intricate type of vocalization in a bird's repertoire and can vary in length and complexity depending on the species. In the majority of cases, they are sung by the male of the species with the intent of establishing and defending a territory or attracting a mate. In contrast, calls, which are usually short bursts of sound characterized by one or a short series of emphatic notes, are used for a variety of purposes: contact and flight calls allow birds to remain in contact with their flock or mates, whereas threat and alarm calls are aggressive in nature and are used to defend territory or warn of a predator respectively. Finally, there are feeding calls, which may be given by either a male or a female while feeding young chicks, and begging calls, given by nestlings or fledglings when they are hungry. </p><p dir="ltr">(4) Not all birds learn to vocalize in the same way. Some species possess inherited abilities, and thus do not need to be taught how to sing their song because they know it intuitively. An experiment was conducted on <strong>the Alder Flycatcher and Willow Flycatcher</strong>, in which young birds were taken from their nests at the age of 10 days. Scientists endeavored to teach each of the young birds the song of the other species involved in the experiment to see if they indeed had an innate knowledge of their own species song. <strong>As it turned out, in spite of the birds being taken out of their environments and surrounded by songs from another species, whose song sounds confusingly similar to their own, the nestlings developed normally and did not mistake their song with that of any other species.</strong></p><br />(5) On the other hand, many other species of bird have to learn their song from an adult "tutor," usually their father. <strong>11A</strong> Without the presence of adults of their own species to imitate, these birds will not develop the ability to sing properly. Some species have a different approach and learn a basic song from their parents and later add to it with improvised melodies that become more layered and complex over time, sometimes to the point that their songs become a separate dialect. <strong>11B</strong> Finally, there are some birds, like the Mockingbird, that have the ability to imitate the songs of other species. <strong>11C</strong> Male Mockingbirds with a wide range of songs in their repertoire are more likely to be older (since it takes time to learn many songs), and this is an attractive trait to female Mockingbirds; older males usually have a larger territory food) and are more experienced, both characteristics of a good father, and therefore highly desirable to the female of the species. <strong>11D</strong></p></section><section><h3><p>What allows some species of birds to make two sounds at the same time?</p></h3><p><p dir="ltr"><strong>READING 1</strong></p><p dir="ltr">Bird Vocalization</p><p dir="ltr">(1) Bird songs are the subject of intense interest among birders and ornithologists around the world, and the beauty and variety of these vocalizations has inspired poets, playwrights and composers alike for centuries. To the untrained ear, differentiating among the thousands of songs and calls that birds create may seem nearly impossible to do. Often times, this massive variation can even exist within one single species. However, just as it is <strong>conceivable</strong> to tell the difference between national and even regional accents in people, so have scientists been able to create an overwhelming catalogue of ornithological vocalizations.</p><p dir="ltr">(2) The basis of a bird’s ability to produce its songs and calls can be found in its anatomy. Unlike the human larynx, which houses the vocal folds, or vocal cords, birds create sounds with two hollow bony structures at the bottom of the trachea called syringes. The fact that each syrinx is located at the bottom of the trachea, where it forks off into the lungs, means that each bronchiole can be used to pass air through the voice boxes, or syringes. These can be controlled independently,</p><p dir="ltr">which explains why some species are capable of making two sounds at once. The syringes vibrate during exhalation, and depending on the tension exerted on them by surrounding muscles, will produce sounds of a different pitch. On the other hand, the volume of any particular sound is determined by the force of the air being exhaled.</p><p dir="ltr">(3) Bird vocalizations can be divided into two general categories: songs and calls. Songs are typically the most intricate type of vocalization in a bird's repertoire and can vary in length and complexity depending on the species. In the majority of cases, they are sung by the male of the species with the intent of establishing and defending a territory or attracting a mate. In contrast, calls, which are usually short bursts of sound characterized by one or a short series of emphatic notes, are used for a variety of purposes: contact and flight calls allow birds to remain in contact with their flock or mates, whereas threat and alarm calls are aggressive in nature and are used to defend territory or warn of a predator respectively. Finally, there are feeding calls, which may be given by either a male or a female while feeding young chicks, and begging calls, given by nestlings or fledglings when they are hungry. </p><p dir="ltr">(4) Not all birds learn to vocalize in the same way. Some species possess inherited abilities, and thus do not need to be taught how to sing their song because they know it intuitively. An experiment was conducted on <strong>the Alder Flycatcher and Willow Flycatcher</strong>, in which young birds were taken from their nests at the age of 10 days. Scientists endeavored to teach each of the young birds the song of the other species involved in the experiment to see if they indeed had an innate knowledge of their own species song. <strong>As it turned out, in spite of the birds being taken out of their environments and surrounded by songs from another species, whose song sounds confusingly similar to their own, the nestlings developed normally and did not mistake their song with that of any other species.</strong></p><br />(5) On the other hand, many other species of bird have to learn their song from an adult "tutor," usually their father. <strong>11A</strong> Without the presence of adults of their own species to imitate, these birds will not develop the ability to sing properly. Some species have a different approach and learn a basic song from their parents and later add to it with improvised melodies that become more layered and complex over time, sometimes to the point that their songs become a separate dialect. <strong>11B</strong> Finally, there are some birds, like the Mockingbird, that have the ability to imitate the songs of other species. <strong>11C</strong> Male Mockingbirds with a wide range of songs in their repertoire are more likely to be older (since it takes time to learn many songs), and this is an attractive trait to female Mockingbirds; older males usually have a larger territory food) and are more experienced, both characteristics of a good father, and therefore highly desirable to the female of the species. <strong>11D</strong></p></section><section><h3>What determines the loudness of a sound a bird makes?</h3><p><p dir="ltr"><strong>READING 1</strong></p><p dir="ltr">Bird Vocalization</p><p dir="ltr">(1) Bird songs are the subject of intense interest among birders and ornithologists around the world, and the beauty and variety of these vocalizations has inspired poets, playwrights and composers alike for centuries. To the untrained ear, differentiating among the thousands of songs and calls that birds create may seem nearly impossible to do. Often times, this massive variation can even exist within one single species. However, just as it is <strong>conceivable</strong> to tell the difference between national and even regional accents in people, so have scientists been able to create an overwhelming catalogue of ornithological vocalizations.</p><p dir="ltr">(2) The basis of a bird’s ability to produce its songs and calls can be found in its anatomy. Unlike the human larynx, which houses the vocal folds, or vocal cords, birds create sounds with two hollow bony structures at the bottom of the trachea called syringes. The fact that each syrinx is located at the bottom of the trachea, where it forks off into the lungs, means that each bronchiole can be used to pass air through the voice boxes, or syringes. These can be controlled independently,</p><p dir="ltr">which explains why some species are capable of making two sounds at once. The syringes vibrate during exhalation, and depending on the tension exerted on them by surrounding muscles, will produce sounds of a different pitch. On the other hand, the volume of any particular sound is determined by the force of the air being exhaled.</p><p dir="ltr">(3) Bird vocalizations can be divided into two general categories: songs and calls. Songs are typically the most intricate type of vocalization in a bird's repertoire and can vary in length and complexity depending on the species. In the majority of cases, they are sung by the male of the species with the intent of establishing and defending a territory or attracting a mate. In contrast, calls, which are usually short bursts of sound characterized by one or a short series of emphatic notes, are used for a variety of purposes: contact and flight calls allow birds to remain in contact with their flock or mates, whereas threat and alarm calls are aggressive in nature and are used to defend territory or warn of a predator respectively. Finally, there are feeding calls, which may be given by either a male or a female while feeding young chicks, and begging calls, given by nestlings or fledglings when they are hungry. </p><p dir="ltr">(4) Not all birds learn to vocalize in the same way. Some species possess inherited abilities, and thus do not need to be taught how to sing their song because they know it intuitively. An experiment was conducted on <strong>the Alder Flycatcher and Willow Flycatcher</strong>, in which young birds were taken from their nests at the age of 10 days. Scientists endeavored to teach each of the young birds the song of the other species involved in the experiment to see if they indeed had an innate knowledge of their own species song. <strong>As it turned out, in spite of the birds being taken out of their environments and surrounded by songs from another species, whose song sounds confusingly similar to their own, the nestlings developed normally and did not mistake their song with that of any other species.</strong></p><br />(5) On the other hand, many other species of bird have to learn their song from an adult "tutor," usually their father. <strong>11A</strong> Without the presence of adults of their own species to imitate, these birds will not develop the ability to sing properly. Some species have a different approach and learn a basic song from their parents and later add to it with improvised melodies that become more layered and complex over time, sometimes to the point that their songs become a separate dialect. <strong>11B</strong> Finally, there are some birds, like the Mockingbird, that have the ability to imitate the songs of other species. <strong>11C</strong> Male Mockingbirds with a wide range of songs in their repertoire are more likely to be older (since it takes time to learn many songs), and this is an attractive trait to female Mockingbirds; older males usually have a larger territory food) and are more experienced, both characteristics of a good father, and therefore highly desirable to the female of the species. <strong>11D</strong></p></section><section><h3>What is NOT mentioned in paragraph 3 as a purpose for calls?<h2 style="text-align:justify;"><strong></strong></h2></h3><p><p dir="ltr"><strong>READING 1</strong></p><p dir="ltr">Bird Vocalization</p><p dir="ltr">(1) Bird songs are the subject of intense interest among birders and ornithologists around the world, and the beauty and variety of these vocalizations has inspired poets, playwrights and composers alike for centuries. To the untrained ear, differentiating among the thousands of songs and calls that birds create may seem nearly impossible to do. Often times, this massive variation can even exist within one single species. However, just as it is <strong>conceivable</strong> to tell the difference between national and even regional accents in people, so have scientists been able to create an overwhelming catalogue of ornithological vocalizations.</p><p dir="ltr">(2) The basis of a bird’s ability to produce its songs and calls can be found in its anatomy. Unlike the human larynx, which houses the vocal folds, or vocal cords, birds create sounds with two hollow bony structures at the bottom of the trachea called syringes. The fact that each syrinx is located at the bottom of the trachea, where it forks off into the lungs, means that each bronchiole can be used to pass air through the voice boxes, or syringes. These can be controlled independently,</p><p dir="ltr">which explains why some species are capable of making two sounds at once. The syringes vibrate during exhalation, and depending on the tension exerted on them by surrounding muscles, will produce sounds of a different pitch. On the other hand, the volume of any particular sound is determined by the force of the air being exhaled.</p><p dir="ltr">(3) Bird vocalizations can be divided into two general categories: songs and calls. Songs are typically the most intricate type of vocalization in a bird's repertoire and can vary in length and complexity depending on the species. In the majority of cases, they are sung by the male of the species with the intent of establishing and defending a territory or attracting a mate. In contrast, calls, which are usually short bursts of sound characterized by one or a short series of emphatic notes, are used for a variety of purposes: contact and flight calls allow birds to remain in contact with their flock or mates, whereas threat and alarm calls are aggressive in nature and are used to defend territory or warn of a predator respectively. Finally, there are feeding calls, which may be given by either a male or a female while feeding young chicks, and begging calls, given by nestlings or fledglings when they are hungry. </p><p dir="ltr">(4) Not all birds learn to vocalize in the same way. Some species possess inherited abilities, and thus do not need to be taught how to sing their song because they know it intuitively. An experiment was conducted on <strong>the Alder Flycatcher and Willow Flycatcher</strong>, in which young birds were taken from their nests at the age of 10 days. Scientists endeavored to teach each of the young birds the song of the other species involved in the experiment to see if they indeed had an innate knowledge of their own species song. <strong>As it turned out, in spite of the birds being taken out of their environments and surrounded by songs from another species, whose song sounds confusingly similar to their own, the nestlings developed normally and did not mistake their song with that of any other species.</strong></p><br />(5) On the other hand, many other species of bird have to learn their song from an adult "tutor," usually their father. <strong>11A</strong> Without the presence of adults of their own species to imitate, these birds will not develop the ability to sing properly. Some species have a different approach and learn a basic song from their parents and later add to it with improvised melodies that become more layered and complex over time, sometimes to the point that their songs become a separate dialect. <strong>11B</strong> Finally, there are some birds, like the Mockingbird, that have the ability to imitate the songs of other species. <strong>11C</strong> Male Mockingbirds with a wide range of songs in their repertoire are more likely to be older (since it takes time to learn many songs), and this is an attractive trait to female Mockingbirds; older males usually have a larger territory food) and are more experienced, both characteristics of a good father, and therefore highly desirable to the female of the species. <strong>11D</strong></p></section><section><h3><p>What is most likely true about fledglings?</p></h3><p></p></section><section><h3><p>Why does the author mention the Alder Flycatcher and Willow Flycatcher in paragraph 4?</p></h3><p><p dir="ltr"><strong>READING 1</strong></p><p dir="ltr">Bird Vocalization</p><p dir="ltr">(1) Bird songs are the subject of intense interest among birders and ornithologists around the world, and the beauty and variety of these vocalizations has inspired poets, playwrights and composers alike for centuries. To the untrained ear, differentiating among the thousands of songs and calls that birds create may seem nearly impossible to do. Often times, this massive variation can even exist within one single species. However, just as it is <strong>conceivable</strong> to tell the difference between national and even regional accents in people, so have scientists been able to create an overwhelming catalogue of ornithological vocalizations.</p><p dir="ltr">(2) The basis of a bird’s ability to produce its songs and calls can be found in its anatomy. Unlike the human larynx, which houses the vocal folds, or vocal cords, birds create sounds with two hollow bony structures at the bottom of the trachea called syringes. The fact that each syrinx is located at the bottom of the trachea, where it forks off into the lungs, means that each bronchiole can be used to pass air through the voice boxes, or syringes. These can be controlled independently,</p><p dir="ltr">which explains why some species are capable of making two sounds at once. The syringes vibrate during exhalation, and depending on the tension exerted on them by surrounding muscles, will produce sounds of a different pitch. On the other hand, the volume of any particular sound is determined by the force of the air being exhaled.</p><p dir="ltr">(3) Bird vocalizations can be divided into two general categories: songs and calls. Songs are typically the most intricate type of vocalization in a bird's repertoire and can vary in length and complexity depending on the species. In the majority of cases, they are sung by the male of the species with the intent of establishing and defending a territory or attracting a mate. In contrast, calls, which are usually short bursts of sound characterized by one or a short series of emphatic notes, are used for a variety of purposes: contact and flight calls allow birds to remain in contact with their flock or mates, whereas threat and alarm calls are aggressive in nature and are used to defend territory or warn of a predator respectively. Finally, there are feeding calls, which may be given by either a male or a female while feeding young chicks, and begging calls, given by nestlings or fledglings when they are hungry. </p><p dir="ltr">(4) Not all birds learn to vocalize in the same way. Some species possess inherited abilities, and thus do not need to be taught how to sing their song because they know it intuitively. An experiment was conducted on <strong>the Alder Flycatcher and Willow Flycatcher</strong>, in which young birds were taken from their nests at the age of 10 days. Scientists endeavored to teach each of the young birds the song of the other species involved in the experiment to see if they indeed had an innate knowledge of their own species song. <strong>As it turned out, in spite of the birds being taken out of their environments and surrounded by songs from another species, whose song sounds confusingly similar to their own, the nestlings developed normally and did not mistake their song with that of any other species.</strong></p><br />(5) On the other hand, many other species of bird have to learn their song from an adult "tutor," usually their father. <strong>11A</strong> Without the presence of adults of their own species to imitate, these birds will not develop the ability to sing properly. Some species have a different approach and learn a basic song from their parents and later add to it with improvised melodies that become more layered and complex over time, sometimes to the point that their songs become a separate dialect. <strong>11B</strong> Finally, there are some birds, like the Mockingbird, that have the ability to imitate the songs of other species. <strong>11C</strong> Male Mockingbirds with a wide range of songs in their repertoire are more likely to be older (since it takes time to learn many songs), and this is an attractive trait to female Mockingbirds; older males usually have a larger territory food) and are more experienced, both characteristics of a good father, and therefore highly desirable to the female of the species. <strong>11D</strong></p></section><section><h3><p>Which of the words below is closest in meaning to innate in paragraph 4?<em></em></p></h3><p><p dir="ltr"><strong>READING 1</strong></p><p dir="ltr">Bird Vocalization</p><p dir="ltr">(1) Bird songs are the subject of intense interest among birders and ornithologists around the world, and the beauty and variety of these vocalizations has inspired poets, playwrights and composers alike for centuries. To the untrained ear, differentiating among the thousands of songs and calls that birds create may seem nearly impossible to do. Often times, this massive variation can even exist within one single species. However, just as it is <strong>conceivable</strong> to tell the difference between national and even regional accents in people, so have scientists been able to create an overwhelming catalogue of ornithological vocalizations.</p><p dir="ltr">(2) The basis of a bird’s ability to produce its songs and calls can be found in its anatomy. Unlike the human larynx, which houses the vocal folds, or vocal cords, birds create sounds with two hollow bony structures at the bottom of the trachea called syringes. The fact that each syrinx is located at the bottom of the trachea, where it forks off into the lungs, means that each bronchiole can be used to pass air through the voice boxes, or syringes. These can be controlled independently,</p><p dir="ltr">which explains why some species are capable of making two sounds at once. The syringes vibrate during exhalation, and depending on the tension exerted on them by surrounding muscles, will produce sounds of a different pitch. On the other hand, the volume of any particular sound is determined by the force of the air being exhaled.</p><p dir="ltr">(3) Bird vocalizations can be divided into two general categories: songs and calls. Songs are typically the most intricate type of vocalization in a bird's repertoire and can vary in length and complexity depending on the species. In the majority of cases, they are sung by the male of the species with the intent of establishing and defending a territory or attracting a mate. In contrast, calls, which are usually short bursts of sound characterized by one or a short series of emphatic notes, are used for a variety of purposes: contact and flight calls allow birds to remain in contact with their flock or mates, whereas threat and alarm calls are aggressive in nature and are used to defend territory or warn of a predator respectively. Finally, there are feeding calls, which may be given by either a male or a female while feeding young chicks, and begging calls, given by nestlings or fledglings when they are hungry. </p><p dir="ltr">(4) Not all birds learn to vocalize in the same way. Some species possess inherited abilities, and thus do not need to be taught how to sing their song because they know it intuitively. An experiment was conducted on <strong>the Alder Flycatcher and Willow Flycatcher</strong>, in which young birds were taken from their nests at the age of 10 days. Scientists endeavored to teach each of the young birds the song of the other species involved in the experiment to see if they indeed had an innate knowledge of their own species song. <strong>As it turned out, in spite of the birds being taken out of their environments and surrounded by songs from another species, whose song sounds confusingly similar to their own, the nestlings developed normally and did not mistake their song with that of any other species.</strong></p><br />(5) On the other hand, many other species of bird have to learn their song from an adult "tutor," usually their father. <strong>11A</strong> Without the presence of adults of their own species to imitate, these birds will not develop the ability to sing properly. Some species have a different approach and learn a basic song from their parents and later add to it with improvised melodies that become more layered and complex over time, sometimes to the point that their songs become a separate dialect. <strong>11B</strong> Finally, there are some birds, like the Mockingbird, that have the ability to imitate the songs of other species. <strong>11C</strong> Male Mockingbirds with a wide range of songs in their repertoire are more likely to be older (since it takes time to learn many songs), and this is an attractive trait to female Mockingbirds; older males usually have a larger territory food) and are more experienced, both characteristics of a good father, and therefore highly desirable to the female of the species. <strong>11D</strong></p></section><section><h3><p>Which of the statements below express the essential information from the highlighted sentence in the passage? Incorrect answer choices will either change the meaning of the original information in important ways, or leave out essential information.</p></h3><p><p dir="ltr"><strong>READING 1</strong></p><p dir="ltr">Bird Vocalization</p><p dir="ltr">(1) Bird songs are the subject of intense interest among birders and ornithologists around the world, and the beauty and variety of these vocalizations has inspired poets, playwrights and composers alike for centuries. To the untrained ear, differentiating among the thousands of songs and calls that birds create may seem nearly impossible to do. Often times, this massive variation can even exist within one single species. However, just as it is <strong>conceivable</strong> to tell the difference between national and even regional accents in people, so have scientists been able to create an overwhelming catalogue of ornithological vocalizations.</p><p dir="ltr">(2) The basis of a bird’s ability to produce its songs and calls can be found in its anatomy. Unlike the human larynx, which houses the vocal folds, or vocal cords, birds create sounds with two hollow bony structures at the bottom of the trachea called syringes. The fact that each syrinx is located at the bottom of the trachea, where it forks off into the lungs, means that each bronchiole can be used to pass air through the voice boxes, or syringes. These can be controlled independently,</p><p dir="ltr">which explains why some species are capable of making two sounds at once. The syringes vibrate during exhalation, and depending on the tension exerted on them by surrounding muscles, will produce sounds of a different pitch. On the other hand, the volume of any particular sound is determined by the force of the air being exhaled.</p><p dir="ltr">(3) Bird vocalizations can be divided into two general categories: songs and calls. Songs are typically the most intricate type of vocalization in a bird's repertoire and can vary in length and complexity depending on the species. In the majority of cases, they are sung by the male of the species with the intent of establishing and defending a territory or attracting a mate. In contrast, calls, which are usually short bursts of sound characterized by one or a short series of emphatic notes, are used for a variety of purposes: contact and flight calls allow birds to remain in contact with their flock or mates, whereas threat and alarm calls are aggressive in nature and are used to defend territory or warn of a predator respectively. Finally, there are feeding calls, which may be given by either a male or a female while feeding young chicks, and begging calls, given by nestlings or fledglings when they are hungry. </p><p dir="ltr">(4) Not all birds learn to vocalize in the same way. Some species possess inherited abilities, and thus do not need to be taught how to sing their song because they know it intuitively. An experiment was conducted on <strong>the Alder Flycatcher and Willow Flycatcher</strong>, in which young birds were taken from their nests at the age of 10 days. Scientists endeavored to teach each of the young birds the song of the other species involved in the experiment to see if they indeed had an innate knowledge of their own species song. <strong>As it turned out, in spite of the birds being taken out of their environments and surrounded by songs from another species, whose song sounds confusingly similar to their own, the nestlings developed normally and did not mistake their song with that of any other species.</strong></p><br />(5) On the other hand, many other species of bird have to learn their song from an adult "tutor," usually their father. <strong>11A</strong> Without the presence of adults of their own species to imitate, these birds will not develop the ability to sing properly. Some species have a different approach and learn a basic song from their parents and later add to it with improvised melodies that become more layered and complex over time, sometimes to the point that their songs become a separate dialect. <strong>11B</strong> Finally, there are some birds, like the Mockingbird, that have the ability to imitate the songs of other species. <strong>11C</strong> Male Mockingbirds with a wide range of songs in their repertoire are more likely to be older (since it takes time to learn many songs), and this is an attractive trait to female Mockingbirds; older males usually have a larger territory food) and are more experienced, both characteristics of a good father, and therefore highly desirable to the female of the species. <strong>11D</strong></p></section><section><h3><p>Read the boldfaced sentence below. Where would the sentence best fit in the passage? It has been suggested that the purpose of this skill is connected to mating.</p></h3><p><p dir="ltr"><strong>READING 1</strong></p><p dir="ltr">Bird Vocalization</p><p dir="ltr">(1) Bird songs are the subject of intense interest among birders and ornithologists around the world, and the beauty and variety of these vocalizations has inspired poets, playwrights and composers alike for centuries. To the untrained ear, differentiating among the thousands of songs and calls that birds create may seem nearly impossible to do. Often times, this massive variation can even exist within one single species. However, just as it is <strong>conceivable</strong> to tell the difference between national and even regional accents in people, so have scientists been able to create an overwhelming catalogue of ornithological vocalizations.</p><p dir="ltr">(2) The basis of a bird’s ability to produce its songs and calls can be found in its anatomy. Unlike the human larynx, which houses the vocal folds, or vocal cords, birds create sounds with two hollow bony structures at the bottom of the trachea called syringes. The fact that each syrinx is located at the bottom of the trachea, where it forks off into the lungs, means that each bronchiole can be used to pass air through the voice boxes, or syringes. These can be controlled independently,</p><p dir="ltr">which explains why some species are capable of making two sounds at once. The syringes vibrate during exhalation, and depending on the tension exerted on them by surrounding muscles, will produce sounds of a different pitch. On the other hand, the volume of any particular sound is determined by the force of the air being exhaled.</p><p dir="ltr">(3) Bird vocalizations can be divided into two general categories: songs and calls. Songs are typically the most intricate type of vocalization in a bird's repertoire and can vary in length and complexity depending on the species. In the majority of cases, they are sung by the male of the species with the intent of establishing and defending a territory or attracting a mate. In contrast, calls, which are usually short bursts of sound characterized by one or a short series of emphatic notes, are used for a variety of purposes: contact and flight calls allow birds to remain in contact with their flock or mates, whereas threat and alarm calls are aggressive in nature and are used to defend territory or warn of a predator respectively. Finally, there are feeding calls, which may be given by either a male or a female while feeding young chicks, and begging calls, given by nestlings or fledglings when they are hungry. </p><p dir="ltr">(4) Not all birds learn to vocalize in the same way. Some species possess inherited abilities, and thus do not need to be taught how to sing their song because they know it intuitively. An experiment was conducted on <strong>the Alder Flycatcher and Willow Flycatcher</strong>, in which young birds were taken from their nests at the age of 10 days. Scientists endeavored to teach each of the young birds the song of the other species involved in the experiment to see if they indeed had an innate knowledge of their own species song. <strong>As it turned out, in spite of the birds being taken out of their environments and surrounded by songs from another species, whose song sounds confusingly similar to their own, the nestlings developed normally and did not mistake their song with that of any other species.</strong></p><br />(5) On the other hand, many other species of bird have to learn their song from an adult "tutor," usually their father. <strong>11A</strong> Without the presence of adults of their own species to imitate, these birds will not develop the ability to sing properly. Some species have a different approach and learn a basic song from their parents and later add to it with improvised melodies that become more layered and complex over time, sometimes to the point that their songs become a separate dialect. <strong>11B</strong> Finally, there are some birds, like the Mockingbird, that have the ability to imitate the songs of other species. <strong>11C</strong> Male Mockingbirds with a wide range of songs in their repertoire are more likely to be older (since it takes time to learn many songs), and this is an attractive trait to female Mockingbirds; older males usually have a larger territory food) and are more experienced, both characteristics of a good father, and therefore highly desirable to the female of the species. <strong>11D</strong></p></section><section><h3><p>It can be inferred that Mockingbirds mimic the songs of other species in order to</p></h3><p><p dir="ltr"><strong>READING 1</strong></p><p dir="ltr">Bird Vocalization</p><p dir="ltr">(1) Bird songs are the subject of intense interest among birders and ornithologists around the world, and the beauty and variety of these vocalizations has inspired poets, playwrights and composers alike for centuries. To the untrained ear, differentiating among the thousands of songs and calls that birds create may seem nearly impossible to do. Often times, this massive variation can even exist within one single species. However, just as it is <strong>conceivable</strong> to tell the difference between national and even regional accents in people, so have scientists been able to create an overwhelming catalogue of ornithological vocalizations.</p><p dir="ltr">(2) The basis of a bird’s ability to produce its songs and calls can be found in its anatomy. Unlike the human larynx, which houses the vocal folds, or vocal cords, birds create sounds with two hollow bony structures at the bottom of the trachea called syringes. The fact that each syrinx is located at the bottom of the trachea, where it forks off into the lungs, means that each bronchiole can be used to pass air through the voice boxes, or syringes. These can be controlled independently,</p><p dir="ltr">which explains why some species are capable of making two sounds at once. The syringes vibrate during exhalation, and depending on the tension exerted on them by surrounding muscles, will produce sounds of a different pitch. On the other hand, the volume of any particular sound is determined by the force of the air being exhaled.</p><p dir="ltr">(3) Bird vocalizations can be divided into two general categories: songs and calls. Songs are typically the most intricate type of vocalization in a bird's repertoire and can vary in length and complexity depending on the species. In the majority of cases, they are sung by the male of the species with the intent of establishing and defending a territory or attracting a mate. In contrast, calls, which are usually short bursts of sound characterized by one or a short series of emphatic notes, are used for a variety of purposes: contact and flight calls allow birds to remain in contact with their flock or mates, whereas threat and alarm calls are aggressive in nature and are used to defend territory or warn of a predator respectively. Finally, there are feeding calls, which may be given by either a male or a female while feeding young chicks, and begging calls, given by nestlings or fledglings when they are hungry. </p><p dir="ltr">(4) Not all birds learn to vocalize in the same way. Some species possess inherited abilities, and thus do not need to be taught how to sing their song because they know it intuitively. An experiment was conducted on <strong>the Alder Flycatcher and Willow Flycatcher</strong>, in which young birds were taken from their nests at the age of 10 days. Scientists endeavored to teach each of the young birds the song of the other species involved in the experiment to see if they indeed had an innate knowledge of their own species song. <strong>As it turned out, in spite of the birds being taken out of their environments and surrounded by songs from another species, whose song sounds confusingly similar to their own, the nestlings developed normally and did not mistake their song with that of any other species.</strong></p><br />(5) On the other hand, many other species of bird have to learn their song from an adult "tutor," usually their father. <strong>11A</strong> Without the presence of adults of their own species to imitate, these birds will not develop the ability to sing properly. Some species have a different approach and learn a basic song from their parents and later add to it with improvised melodies that become more layered and complex over time, sometimes to the point that their songs become a separate dialect. <strong>11B</strong> Finally, there are some birds, like the Mockingbird, that have the ability to imitate the songs of other species. <strong>11C</strong> Male Mockingbirds with a wide range of songs in their repertoire are more likely to be older (since it takes time to learn many songs), and this is an attractive trait to female Mockingbirds; older males usually have a larger territory food) and are more experienced, both characteristics of a good father, and therefore highly desirable to the female of the species. <strong>11D</strong></p></section><section><h3><p>According to paragraph 1, what is true of scientists in the 1600s?</p></h3><p><p dir="ltr"><strong></strong><strong>READING 2</strong></p><p dir="ltr">ENZYMES AND SUBSTRATES</p><p dir="ltr">(1) Although the digestion of meat in the stomach and the conversion of starch into sugars were familiar to scientists as early as the 17th century, the processes by which these took place had not yet been recognized. In 1833, experiments were conducted by Anselme Payen and Jean-Francois Persoz, chemists at a French sugar factory. They discovered the enzyme diastase, which causes the conversion of starch into maltose. Several decades later, Lou is Pasteur realized that the conversion of sugar into alcohol by yeast was a result of a "vital force" within the yeast cells, which he termed "ferments." Since then, advances in technology have led to a more <strong>comprehensive </strong>understanding of the form and function of these specialized proteins, called enzymes, without which life would not be possible.</p><p dir="ltr">(2) Enzymes, which are recognized as the body's metabolic catalysts (a substance that causes a chemical reaction), are responsible for thousands of very specific chemical reactions that transform certain molecules into the substances that support life. These reactions happen with what are termed substrates, molecules that, when they bind with a specific enzyme, form products. <strong>These</strong> are the substances that maintain all the systems in the body. Enzymes are categorized based on the type of reaction they catalyze, and on which substrates they act on. Almost all enzymes, with very few exceptions, have names that end in -ase. Lactase acts on transforming lactose, found naturally in milk, into glucose, also known as blood sugar. Amylases catalyze starches into sugars and proteases catalyze proteins.</p><p dir="ltr">"(3) Enzymes will only bond with certain molecules, and this trait is known as specificity. In 1894, Emil Fischer, Nobel Prize laureate, suggested that enzymes and their substrates functioned according to the "Lock and Key" model. The theory describes the specificity of the reactions between enzymes and substrates like that of a lock that only one key will successfully open. Enzymes and substrates bond at the "active site" of the enzyme, and each enzyme's active site is shaped in a very particular way and this allows it to precisely fit its intended substrate. If a substrate tries to bond with an unintended enzyme, no catalytic action will take place. Although this model effectively explains the specificity of enzymes, it does not make clear how substrates maintain their bond with enzymes during the catalytic reaction. It was proposed by Daniel Koshland in 1958 that the active site of enzymes is composed of flexible amino acid side-chains, and this fact is what allows enzymes to remain bonded with the substrates until the reaction has reached completion and its product can be released.</p><p dir="ltr">"(4) Enzymes not only allow for specificity of reactions, but also for these to happen at the speed necessary for life. Without enzymes, reactions would happen, but at such a slow rate that it would be impossible to <strong>sustain</strong> life. Enzymes speed up the rate of reaction up to millions of times faster than an uncatalyzed reaction. <strong>Consequently, the products necessary for life are formed more quickly, and post-reaction equilibrium (when the opposing forces involved in the reaction have reached a state of balance) is achieved much faster.</strong> Like all catalysts, enzymes are not changed by the reactions they catalyze. Once a reaction has ended and the resulting product is released, the enzyme returns to its original form, and awaits another substrate to bond with, and the process continues in this way indefinitely.</p><p dir="ltr">(5) There are two main categories of enzymes in our bodies: digestive and systemic. Enzymes that function in the digestive tract act to break down food into its smaller components, which can then be absorbed by the different systems that use them. For instance, the enzyme lipase is what catalyzes the hydrolysis (the process of <strong>breaking down</strong> the chemical bonds in a molecule with water) of fats, or lipids. Without lipases, the proper digestion of lipids would not be possible, and their vital functions in the body (including providing energy storage and structural components of cell walls) would not occur. <strong>26A</strong> Systemic enzymes are found in the blood, tissues, and every cell of the body. <strong>26B</strong> They perform such essential roles as preventing blood clots and inflammation as well as providing powerful antioxidant effects. <strong>26C</strong> When a group of enzymes is unable to function optimally, the results can be catastrophic. <strong>26D</strong></p><strong></strong></p></section><section><h3><p>Which of the words below could best replace comprehensive from paragraph 1?</p></h3><p><p dir="ltr"><strong>READING 2</strong></p><p dir="ltr">ENZYMES AND SUBSTRATES</p><p dir="ltr">(1) Although the digestion of meat in the stomach and the conversion of starch into sugars were familiar to scientists as early as the 17th century, the processes by which these took place had not yet been recognized. In 1833, experiments were conducted by Anselme Payen and Jean-Francois Persoz, chemists at a French sugar factory. They discovered the enzyme diastase, which causes the conversion of starch into maltose. Several decades later, Lou is Pasteur realized that the conversion of sugar into alcohol by yeast was a result of a "vital force" within the yeast cells, which he termed "ferments." Since then, advances in technology have led to a more <strong>comprehensive </strong>understanding of the form and function of these specialized proteins, called enzymes, without which life would not be possible.</p><p dir="ltr">(2) Enzymes, which are recognized as the body's metabolic catalysts (a substance that causes a chemical reaction), are responsible for thousands of very specific chemical reactions that transform certain molecules into the substances that support life. These reactions happen with what are termed substrates, molecules that, when they bind with a specific enzyme, form products. <strong>These</strong> are the substances that maintain all the systems in the body. Enzymes are categorized based on the type of reaction they catalyze, and on which substrates they act on. Almost all enzymes, with very few exceptions, have names that end in -ase. Lactase acts on transforming lactose, found naturally in milk, into glucose, also known as blood sugar. Amylases catalyze starches into sugars and proteases catalyze proteins.</p><p dir="ltr">"(3) Enzymes will only bond with certain molecules, and this trait is known as specificity. In 1894, Emil Fischer, Nobel Prize laureate, suggested that enzymes and their substrates functioned according to the "Lock and Key" model. The theory describes the specificity of the reactions between enzymes and substrates like that of a lock that only one key will successfully open. Enzymes and substrates bond at the "active site" of the enzyme, and each enzyme's active site is shaped in a very particular way and this allows it to precisely fit its intended substrate. If a substrate tries to bond with an unintended enzyme, no catalytic action will take place. Although this model effectively explains the specificity of enzymes, it does not make clear how substrates maintain their bond with enzymes during the catalytic reaction. It was proposed by Daniel Koshland in 1958 that the active site of enzymes is composed of flexible amino acid side-chains, and this fact is what allows enzymes to remain bonded with the substrates until the reaction has reached completion and its product can be released.</p><p dir="ltr">"(4) Enzymes not only allow for specificity of reactions, but also for these to happen at the speed necessary for life. Without enzymes, reactions would happen, but at such a slow rate that it would be impossible to <strong>sustain</strong> life. Enzymes speed up the rate of reaction up to millions of times faster than an uncatalyzed reaction. <strong>Consequently, the products necessary for life are formed more quickly, and post-reaction equilibrium (when the opposing forces involved in the reaction have reached a state of balance) is achieved much faster.</strong> Like all catalysts, enzymes are not changed by the reactions they catalyze. Once a reaction has ended and the resulting product is released, the enzyme returns to its original form, and awaits another substrate to bond with, and the process continues in this way indefinitely.</p><p dir="ltr">(5) There are two main categories of enzymes in our bodies: digestive and systemic. Enzymes that function in the digestive tract act to break down food into its smaller components, which can then be absorbed by the different systems that use them. For instance, the enzyme lipase is what catalyzes the hydrolysis (the process of <strong>breaking down</strong> the chemical bonds in a molecule with water) of fats, or lipids. Without lipases, the proper digestion of lipids would not be possible, and their vital functions in the body (including providing energy storage and structural components of cell walls) would not occur. <strong>26A</strong> Systemic enzymes are found in the blood, tissues, and every cell of the body. <strong>26B</strong> They perform such essential roles as preventing blood clots and inflammation as well as providing powerful antioxidant effects. <strong>26C</strong> When a group of enzymes is unable to function optimally, the results can be catastrophic. <strong>26D</strong></p></p></section><section><h3><p>According to paragraph 2, what is the definition of an enzyme?</p></h3><p><p dir="ltr"><strong>READING 2</strong></p><p dir="ltr">ENZYMES AND SUBSTRATES</p><p dir="ltr">(1) Although the digestion of meat in the stomach and the conversion of starch into sugars were familiar to scientists as early as the 17th century, the processes by which these took place had not yet been recognized. In 1833, experiments were conducted by Anselme Payen and Jean-Francois Persoz, chemists at a French sugar factory. They discovered the enzyme diastase, which causes the conversion of starch into maltose. Several decades later, Lou is Pasteur realized that the conversion of sugar into alcohol by yeast was a result of a "vital force" within the yeast cells, which he termed "ferments." Since then, advances in technology have led to a more <strong>comprehensive </strong>understanding of the form and function of these specialized proteins, called enzymes, without which life would not be possible.</p><p dir="ltr">(2) Enzymes, which are recognized as the body's metabolic catalysts (a substance that causes a chemical reaction), are responsible for thousands of very specific chemical reactions that transform certain molecules into the substances that support life. These reactions happen with what are termed substrates, molecules that, when they bind with a specific enzyme, form products. <strong>These</strong> are the substances that maintain all the systems in the body. Enzymes are categorized based on the type of reaction they catalyze, and on which substrates they act on. Almost all enzymes, with very few exceptions, have names that end in -ase. Lactase acts on transforming lactose, found naturally in milk, into glucose, also known as blood sugar. Amylases catalyze starches into sugars and proteases catalyze proteins.</p><p dir="ltr">"(3) Enzymes will only bond with certain molecules, and this trait is known as specificity. In 1894, Emil Fischer, Nobel Prize laureate, suggested that enzymes and their substrates functioned according to the "Lock and Key" model. The theory describes the specificity of the reactions between enzymes and substrates like that of a lock that only one key will successfully open. Enzymes and substrates bond at the "active site" of the enzyme, and each enzyme's active site is shaped in a very particular way and this allows it to precisely fit its intended substrate. If a substrate tries to bond with an unintended enzyme, no catalytic action will take place. Although this model effectively explains the specificity of enzymes, it does not make clear how substrates maintain their bond with enzymes during the catalytic reaction. It was proposed by Daniel Koshland in 1958 that the active site of enzymes is composed of flexible amino acid side-chains, and this fact is what allows enzymes to remain bonded with the substrates until the reaction has reached completion and its product can be released.</p><p dir="ltr">"(4) Enzymes not only allow for specificity of reactions, but also for these to happen at the speed necessary for life. Without enzymes, reactions would happen, but at such a slow rate that it would be impossible to <strong>sustain</strong> life. Enzymes speed up the rate of reaction up to millions of times faster than an uncatalyzed reaction. <strong>Consequently, the products necessary for life are formed more quickly, and post-reaction equilibrium (when the opposing forces involved in the reaction have reached a state of balance) is achieved much faster.</strong> Like all catalysts, enzymes are not changed by the reactions they catalyze. Once a reaction has ended and the resulting product is released, the enzyme returns to its original form, and awaits another substrate to bond with, and the process continues in this way indefinitely.</p><p dir="ltr">(5) There are two main categories of enzymes in our bodies: digestive and systemic. Enzymes that function in the digestive tract act to break down food into its smaller components, which can then be absorbed by the different systems that use them. For instance, the enzyme lipase is what catalyzes the hydrolysis (the process of <strong>breaking down</strong> the chemical bonds in a molecule with water) of fats, or lipids. Without lipases, the proper digestion of lipids would not be possible, and their vital functions in the body (including providing energy storage and structural components of cell walls) would not occur. <strong>26A</strong> Systemic enzymes are found in the blood, tissues, and every cell of the body. <strong>26B</strong> They perform such essential roles as preventing blood clots and inflammation as well as providing powerful antioxidant effects. <strong>26C</strong> When a group of enzymes is unable to function optimally, the results can be catastrophic. <strong>26D</strong></p></p></section><section><h3><p>What does the word <strong>These</strong> refer to in paragraph 2?</p></h3><p><p dir="ltr"><strong>READING 2</strong></p><p dir="ltr">ENZYMES AND SUBSTRATES</p><p dir="ltr">(1) Although the digestion of meat in the stomach and the conversion of starch into sugars were familiar to scientists as early as the 17th century, the processes by which these took place had not yet been recognized. In 1833, experiments were conducted by Anselme Payen and Jean-Francois Persoz, chemists at a French sugar factory. They discovered the enzyme diastase, which causes the conversion of starch into maltose. Several decades later, Lou is Pasteur realized that the conversion of sugar into alcohol by yeast was a result of a "vital force" within the yeast cells, which he termed "ferments." Since then, advances in technology have led to a more <strong>comprehensive </strong>understanding of the form and function of these specialized proteins, called enzymes, without which life would not be possible.</p><p dir="ltr">(2) Enzymes, which are recognized as the body's metabolic catalysts (a substance that causes a chemical reaction), are responsible for thousands of very specific chemical reactions that transform certain molecules into the substances that support life. These reactions happen with what are termed substrates, molecules that, when they bind with a specific enzyme, form products. <strong>These</strong> are the substances that maintain all the systems in the body. Enzymes are categorized based on the type of reaction they catalyze, and on which substrates they act on. Almost all enzymes, with very few exceptions, have names that end in -ase. Lactase acts on transforming lactose, found naturally in milk, into glucose, also known as blood sugar. Amylases catalyze starches into sugars and proteases catalyze proteins.</p><p dir="ltr">"(3) Enzymes will only bond with certain molecules, and this trait is known as specificity. In 1894, Emil Fischer, Nobel Prize laureate, suggested that enzymes and their substrates functioned according to the "Lock and Key" model. The theory describes the specificity of the reactions between enzymes and substrates like that of a lock that only one key will successfully open. Enzymes and substrates bond at the "active site" of the enzyme, and each enzyme's active site is shaped in a very particular way and this allows it to precisely fit its intended substrate. If a substrate tries to bond with an unintended enzyme, no catalytic action will take place. Although this model effectively explains the specificity of enzymes, it does not make clear how substrates maintain their bond with enzymes during the catalytic reaction. It was proposed by Daniel Koshland in 1958 that the active site of enzymes is composed of flexible amino acid side-chains, and this fact is what allows enzymes to remain bonded with the substrates until the reaction has reached completion and its product can be released.</p><p dir="ltr">"(4) Enzymes not only allow for specificity of reactions, but also for these to happen at the speed necessary for life. Without enzymes, reactions would happen, but at such a slow rate that it would be impossible to <strong>sustain</strong> life. Enzymes speed up the rate of reaction up to millions of times faster than an uncatalyzed reaction. <strong>Consequently, the products necessary for life are formed more quickly, and post-reaction equilibrium (when the opposing forces involved in the reaction have reached a state of balance) is achieved much faster.</strong> Like all catalysts, enzymes are not changed by the reactions they catalyze. Once a reaction has ended and the resulting product is released, the enzyme returns to its original form, and awaits another substrate to bond with, and the process continues in this way indefinitely.</p><p dir="ltr">(5) There are two main categories of enzymes in our bodies: digestive and systemic. Enzymes that function in the digestive tract act to break down food into its smaller components, which can then be absorbed by the different systems that use them. For instance, the enzyme lipase is what catalyzes the hydrolysis (the process of <strong>breaking down</strong> the chemical bonds in a molecule with water) of fats, or lipids. Without lipases, the proper digestion of lipids would not be possible, and their vital functions in the body (including providing energy storage and structural components of cell walls) would not occur. <strong>26A</strong> Systemic enzymes are found in the blood, tissues, and every cell of the body. <strong>26B</strong> They perform such essential roles as preventing blood clots and inflammation as well as providing powerful antioxidant effects. <strong>26C</strong> When a group of enzymes is unable to function optimally, the results can be catastrophic. <strong>26D</strong></p></p></section><section><h3><p>It can be inferred from the passage that</p></h3><p><p dir="ltr"></p><p dir="ltr"><strong>READING 2</strong></p><p dir="ltr">ENZYMES AND SUBSTRATES</p><p dir="ltr">(1) Although the digestion of meat in the stomach and the conversion of starch into sugars were familiar to scientists as early as the 17th century, the processes by which these took place had not yet been recognized. In 1833, experiments were conducted by Anselme Payen and Jean-Francois Persoz, chemists at a French sugar factory. They discovered the enzyme diastase, which causes the conversion of starch into maltose. Several decades later, Lou is Pasteur realized that the conversion of sugar into alcohol by yeast was a result of a "vital force" within the yeast cells, which he termed "ferments." Since then, advances in technology have led to a more <strong>comprehensive </strong>understanding of the form and function of these specialized proteins, called enzymes, without which life would not be possible.</p><p dir="ltr">(2) Enzymes, which are recognized as the body's metabolic catalysts (a substance that causes a chemical reaction), are responsible for thousands of very specific chemical reactions that transform certain molecules into the substances that support life. These reactions happen with what are termed substrates, molecules that, when they bind with a specific enzyme, form products. <strong>These</strong> are the substances that maintain all the systems in the body. Enzymes are categorized based on the type of reaction they catalyze, and on which substrates they act on. Almost all enzymes, with very few exceptions, have names that end in -ase. Lactase acts on transforming lactose, found naturally in milk, into glucose, also known as blood sugar. Amylases catalyze starches into sugars and proteases catalyze proteins.</p><p dir="ltr">"(3) Enzymes will only bond with certain molecules, and this trait is known as specificity. In 1894, Emil Fischer, Nobel Prize laureate, suggested that enzymes and their substrates functioned according to the "Lock and Key" model. The theory describes the specificity of the reactions between enzymes and substrates like that of a lock that only one key will successfully open. Enzymes and substrates bond at the "active site" of the enzyme, and each enzyme's active site is shaped in a very particular way and this allows it to precisely fit its intended substrate. If a substrate tries to bond with an unintended enzyme, no catalytic action will take place. Although this model effectively explains the specificity of enzymes, it does not make clear how substrates maintain their bond with enzymes during the catalytic reaction. It was proposed by Daniel Koshland in 1958 that the active site of enzymes is composed of flexible amino acid side-chains, and this fact is what allows enzymes to remain bonded with the substrates until the reaction has reached completion and its product can be released.</p><p dir="ltr">"(4) Enzymes not only allow for specificity of reactions, but also for these to happen at the speed necessary for life. Without enzymes, reactions would happen, but at such a slow rate that it would be impossible to <strong>sustain</strong> life. Enzymes speed up the rate of reaction up to millions of times faster than an uncatalyzed reaction. <strong>Consequently, the products necessary for life are formed more quickly, and post-reaction equilibrium (when the opposing forces involved in the reaction have reached a state of balance) is achieved much faster.</strong> Like all catalysts, enzymes are not changed by the reactions they catalyze. Once a reaction has ended and the resulting product is released, the enzyme returns to its original form, and awaits another substrate to bond with, and the process continues in this way indefinitely.</p><p dir="ltr">(5) There are two main categories of enzymes in our bodies: digestive and systemic. Enzymes that function in the digestive tract act to break down food into its smaller components, which can then be absorbed by the different systems that use them. For instance, the enzyme lipase is what catalyzes the hydrolysis (the process of <strong>breaking down</strong> the chemical bonds in a molecule with water) of fats, or lipids. Without lipases, the proper digestion of lipids would not be possible, and their vital functions in the body (including providing energy storage and structural components of cell walls) would not occur. <strong>26A</strong> Systemic enzymes are found in the blood, tissues, and every cell of the body. <strong>26B</strong> They perform such essential roles as preventing blood clots and inflammation as well as providing powerful antioxidant effects. <strong>26C</strong> When a group of enzymes is unable to function optimally, the results can be catastrophic. <strong>26D</strong></p></p></section><section><h3><p>The author mentions the phrase <strong>each enzyme’s active site is shaped in a very particular way </strong>in paragraph 3 in order to</p></h3><p><p dir="ltr"></p><p dir="ltr"><strong>READING 2</strong></p><p dir="ltr">ENZYMES AND SUBSTRATES</p><p dir="ltr">(1) Although the digestion of meat in the stomach and the conversion of starch into sugars were familiar to scientists as early as the 17th century, the processes by which these took place had not yet been recognized. In 1833, experiments were conducted by Anselme Payen and Jean-Francois Persoz, chemists at a French sugar factory. They discovered the enzyme diastase, which causes the conversion of starch into maltose. Several decades later, Lou is Pasteur realized that the conversion of sugar into alcohol by yeast was a result of a "vital force" within the yeast cells, which he termed "ferments." Since then, advances in technology have led to a more <strong>comprehensive </strong>understanding of the form and function of these specialized proteins, called enzymes, without which life would not be possible.</p><p dir="ltr">(2) Enzymes, which are recognized as the body's metabolic catalysts (a substance that causes a chemical reaction), are responsible for thousands of very specific chemical reactions that transform certain molecules into the substances that support life. These reactions happen with what are termed substrates, molecules that, when they bind with a specific enzyme, form products. <strong>These</strong> are the substances that maintain all the systems in the body. Enzymes are categorized based on the type of reaction they catalyze, and on which substrates they act on. Almost all enzymes, with very few exceptions, have names that end in -ase. Lactase acts on transforming lactose, found naturally in milk, into glucose, also known as blood sugar. Amylases catalyze starches into sugars and proteases catalyze proteins.</p><p dir="ltr">"(3) Enzymes will only bond with certain molecules, and this trait is known as specificity. In 1894, Emil Fischer, Nobel Prize laureate, suggested that enzymes and their substrates functioned according to the "Lock and Key" model. The theory describes the specificity of the reactions between enzymes and substrates like that of a lock that only one key will successfully open. Enzymes and substrates bond at the "active site" of the enzyme, and each enzyme's active site is shaped in a very particular way and this allows it to precisely fit its intended substrate. If a substrate tries to bond with an unintended enzyme, no catalytic action will take place. Although this model effectively explains the specificity of enzymes, it does not make clear how substrates maintain their bond with enzymes during the catalytic reaction. It was proposed by Daniel Koshland in 1958 that the active site of enzymes is composed of flexible amino acid side-chains, and this fact is what allows enzymes to remain bonded with the substrates until the reaction has reached completion and its product can be released.</p><p dir="ltr">"(4) Enzymes not only allow for specificity of reactions, but also for these to happen at the speed necessary for life. Without enzymes, reactions would happen, but at such a slow rate that it would be impossible to <strong>sustain</strong> life. Enzymes speed up the rate of reaction up to millions of times faster than an uncatalyzed reaction. <strong>Consequently, the products necessary for life are formed more quickly, and post-reaction equilibrium (when the opposing forces involved in the reaction have reached a state of balance) is achieved much faster.</strong> Like all catalysts, enzymes are not changed by the reactions they catalyze. Once a reaction has ended and the resulting product is released, the enzyme returns to its original form, and awaits another substrate to bond with, and the process continues in this way indefinitely.</p><p dir="ltr">(5) There are two main categories of enzymes in our bodies: digestive and systemic. Enzymes that function in the digestive tract act to break down food into its smaller components, which can then be absorbed by the different systems that use them. For instance, the enzyme lipase is what catalyzes the hydrolysis (the process of <strong>breaking down</strong> the chemical bonds in a molecule with water) of fats, or lipids. Without lipases, the proper digestion of lipids would not be possible, and their vital functions in the body (including providing energy storage and structural components of cell walls) would not occur. <strong>26A</strong> Systemic enzymes are found in the blood, tissues, and every cell of the body. <strong>26B</strong> They perform such essential roles as preventing blood clots and inflammation as well as providing powerful antioxidant effects. <strong>26C</strong> When a group of enzymes is unable to function optimally, the results can be catastrophic. <strong>26D</strong></p></p></section><section><h3><p>What does the author imply about the bonds between enzymes and their substrates?</p></h3><p><p dir="ltr"></p><p dir="ltr"><strong>READING 2</strong></p><p dir="ltr">ENZYMES AND SUBSTRATES</p><p dir="ltr">(1) Although the digestion of meat in the stomach and the conversion of starch into sugars were familiar to scientists as early as the 17th century, the processes by which these took place had not yet been recognized. In 1833, experiments were conducted by Anselme Payen and Jean-Francois Persoz, chemists at a French sugar factory. They discovered the enzyme diastase, which causes the conversion of starch into maltose. Several decades later, Lou is Pasteur realized that the conversion of sugar into alcohol by yeast was a result of a "vital force" within the yeast cells, which he termed "ferments." Since then, advances in technology have led to a more <strong>comprehensive </strong>understanding of the form and function of these specialized proteins, called enzymes, without which life would not be possible.</p><p dir="ltr">(2) Enzymes, which are recognized as the body's metabolic catalysts (a substance that causes a chemical reaction), are responsible for thousands of very specific chemical reactions that transform certain molecules into the substances that support life. These reactions happen with what are termed substrates, molecules that, when they bind with a specific enzyme, form products. <strong>These</strong> are the substances that maintain all the systems in the body. Enzymes are categorized based on the type of reaction they catalyze, and on which substrates they act on. Almost all enzymes, with very few exceptions, have names that end in -ase. Lactase acts on transforming lactose, found naturally in milk, into glucose, also known as blood sugar. Amylases catalyze starches into sugars and proteases catalyze proteins.</p><p dir="ltr">"(3) Enzymes will only bond with certain molecules, and this trait is known as specificity. In 1894, Emil Fischer, Nobel Prize laureate, suggested that enzymes and their substrates functioned according to the "Lock and Key" model. The theory describes the specificity of the reactions between enzymes and substrates like that of a lock that only one key will successfully open. Enzymes and substrates bond at the "active site" of the enzyme, and each enzyme's active site is shaped in a very particular way and this allows it to precisely fit its intended substrate. If a substrate tries to bond with an unintended enzyme, no catalytic action will take place. Although this model effectively explains the specificity of enzymes, it does not make clear how substrates maintain their bond with enzymes during the catalytic reaction. It was proposed by Daniel Koshland in 1958 that the active site of enzymes is composed of flexible amino acid side-chains, and this fact is what allows enzymes to remain bonded with the substrates until the reaction has reached completion and its product can be released.</p><p dir="ltr">"(4) Enzymes not only allow for specificity of reactions, but also for these to happen at the speed necessary for life. Without enzymes, reactions would happen, but at such a slow rate that it would be impossible to <strong>sustain</strong> life. Enzymes speed up the rate of reaction up to millions of times faster than an uncatalyzed reaction. <strong>Consequently, the products necessary for life are formed more quickly, and post-reaction equilibrium (when the opposing forces involved in the reaction have reached a state of balance) is achieved much faster.</strong> Like all catalysts, enzymes are not changed by the reactions they catalyze. Once a reaction has ended and the resulting product is released, the enzyme returns to its original form, and awaits another substrate to bond with, and the process continues in this way indefinitely.</p><p dir="ltr">(5) There are two main categories of enzymes in our bodies: digestive and systemic. Enzymes that function in the digestive tract act to break down food into its smaller components, which can then be absorbed by the different systems that use them. For instance, the enzyme lipase is what catalyzes the hydrolysis (the process of <strong>breaking down</strong> the chemical bonds in a molecule with water) of fats, or lipids. Without lipases, the proper digestion of lipids would not be possible, and their vital functions in the body (including providing energy storage and structural components of cell walls) would not occur. <strong>26A</strong> Systemic enzymes are found in the blood, tissues, and every cell of the body. <strong>26B</strong> They perform such essential roles as preventing blood clots and inflammation as well as providing powerful antioxidant effects. <strong>26C</strong> When a group of enzymes is unable to function optimally, the results can be catastrophic. <strong>26D</strong></p><p dir="ltr"></p><br /></p></section><section><h3><p>Which of the words below best expresses the meaning of sustain in paragraph 4</p></h3><p><p dir="ltr"></p><p dir="ltr"><strong>READING 2</strong></p><p dir="ltr">ENZYMES AND SUBSTRATES</p><p dir="ltr">(1) Although the digestion of meat in the stomach and the conversion of starch into sugars were familiar to scientists as early as the 17th century, the processes by which these took place had not yet been recognized. In 1833, experiments were conducted by Anselme Payen and Jean-Francois Persoz, chemists at a French sugar factory. They discovered the enzyme diastase, which causes the conversion of starch into maltose. Several decades later, Lou is Pasteur realized that the conversion of sugar into alcohol by yeast was a result of a "vital force" within the yeast cells, which he termed "ferments." Since then, advances in technology have led to a more <strong>comprehensive </strong>understanding of the form and function of these specialized proteins, called enzymes, without which life would not be possible.</p><p dir="ltr">(2) Enzymes, which are recognized as the body's metabolic catalysts (a substance that causes a chemical reaction), are responsible for thousands of very specific chemical reactions that transform certain molecules into the substances that support life. These reactions happen with what are termed substrates, molecules that, when they bind with a specific enzyme, form products. <strong>These</strong> are the substances that maintain all the systems in the body. Enzymes are categorized based on the type of reaction they catalyze, and on which substrates they act on. Almost all enzymes, with very few exceptions, have names that end in -ase. Lactase acts on transforming lactose, found naturally in milk, into glucose, also known as blood sugar. Amylases catalyze starches into sugars and proteases catalyze proteins.</p><p dir="ltr">"(3) Enzymes will only bond with certain molecules, and this trait is known as specificity. In 1894, Emil Fischer, Nobel Prize laureate, suggested that enzymes and their substrates functioned according to the "Lock and Key" model. The theory describes the specificity of the reactions between enzymes and substrates like that of a lock that only one key will successfully open. Enzymes and substrates bond at the "active site" of the enzyme, and each enzyme's active site is shaped in a very particular way and this allows it to precisely fit its intended substrate. If a substrate tries to bond with an unintended enzyme, no catalytic action will take place. Although this model effectively explains the specificity of enzymes, it does not make clear how substrates maintain their bond with enzymes during the catalytic reaction. It was proposed by Daniel Koshland in 1958 that the active site of enzymes is composed of flexible amino acid side-chains, and this fact is what allows enzymes to remain bonded with the substrates until the reaction has reached completion and its product can be released.</p><p dir="ltr">"(4) Enzymes not only allow for specificity of reactions, but also for these to happen at the speed necessary for life. Without enzymes, reactions would happen, but at such a slow rate that it would be impossible to <strong>sustain</strong> life. Enzymes speed up the rate of reaction up to millions of times faster than an uncatalyzed reaction. <strong>Consequently, the products necessary for life are formed more quickly, and post-reaction equilibrium (when the opposing forces involved in the reaction have reached a state of balance) is achieved much faster.</strong> Like all catalysts, enzymes are not changed by the reactions they catalyze. Once a reaction has ended and the resulting product is released, the enzyme returns to its original form, and awaits another substrate to bond with, and the process continues in this way indefinitely.</p><p dir="ltr">(5) There are two main categories of enzymes in our bodies: digestive and systemic. Enzymes that function in the digestive tract act to break down food into its smaller components, which can then be absorbed by the different systems that use them. For instance, the enzyme lipase is what catalyzes the hydrolysis (the process of <strong>breaking down</strong> the chemical bonds in a molecule with water) of fats, or lipids. Without lipases, the proper digestion of lipids would not be possible, and their vital functions in the body (including providing energy storage and structural components of cell walls) would not occur. <strong>26A</strong> Systemic enzymes are found in the blood, tissues, and every cell of the body. <strong>26B</strong> They perform such essential roles as preventing blood clots and inflammation as well as providing powerful antioxidant effects. <strong>26C</strong> When a group of enzymes is unable to function optimally, the results can be catastrophic. <strong>26D</strong></p><p dir="ltr"></p><br /></p></section><section><h3><p>Which of the statements below express the essential information from the highlighted sentence in the passage? Wrong answer choices will either change the meaning of the original information in important ways, or leave out essential information</p></h3><p><p dir="ltr"></p><p dir="ltr"><strong>READING 2</strong></p><p dir="ltr">ENZYMES AND SUBSTRATES</p><p dir="ltr">(1) Although the digestion of meat in the stomach and the conversion of starch into sugars were familiar to scientists as early as the 17th century, the processes by which these took place had not yet been recognized. In 1833, experiments were conducted by Anselme Payen and Jean-Francois Persoz, chemists at a French sugar factory. They discovered the enzyme diastase, which causes the conversion of starch into maltose. Several decades later, Lou is Pasteur realized that the conversion of sugar into alcohol by yeast was a result of a "vital force" within the yeast cells, which he termed "ferments." Since then, advances in technology have led to a more <strong>comprehensive </strong>understanding of the form and function of these specialized proteins, called enzymes, without which life would not be possible.</p><p dir="ltr">(2) Enzymes, which are recognized as the body's metabolic catalysts (a substance that causes a chemical reaction), are responsible for thousands of very specific chemical reactions that transform certain molecules into the substances that support life. These reactions happen with what are termed substrates, molecules that, when they bind with a specific enzyme, form products. <strong>These</strong> are the substances that maintain all the systems in the body. Enzymes are categorized based on the type of reaction they catalyze, and on which substrates they act on. Almost all enzymes, with very few exceptions, have names that end in -ase. Lactase acts on transforming lactose, found naturally in milk, into glucose, also known as blood sugar. Amylases catalyze starches into sugars and proteases catalyze proteins.</p><p dir="ltr">"(3) Enzymes will only bond with certain molecules, and this trait is known as specificity. In 1894, Emil Fischer, Nobel Prize laureate, suggested that enzymes and their substrates functioned according to the "Lock and Key" model. The theory describes the specificity of the reactions between enzymes and substrates like that of a lock that only one key will successfully open. Enzymes and substrates bond at the "active site" of the enzyme, and each enzyme's active site is shaped in a very particular way and this allows it to precisely fit its intended substrate. If a substrate tries to bond with an unintended enzyme, no catalytic action will take place. Although this model effectively explains the specificity of enzymes, it does not make clear how substrates maintain their bond with enzymes during the catalytic reaction. It was proposed by Daniel Koshland in 1958 that the active site of enzymes is composed of flexible amino acid side-chains, and this fact is what allows enzymes to remain bonded with the substrates until the reaction has reached completion and its product can be released.</p><p dir="ltr">"(4) Enzymes not only allow for specificity of reactions, but also for these to happen at the speed necessary for life. Without enzymes, reactions would happen, but at such a slow rate that it would be impossible to <strong>sustain</strong> life. Enzymes speed up the rate of reaction up to millions of times faster than an uncatalyzed reaction. <strong>Consequently, the products necessary for life are formed more quickly, and post-reaction equilibrium (when the opposing forces involved in the reaction have reached a state of balance) is achieved much faster.</strong> Like all catalysts, enzymes are not changed by the reactions they catalyze. Once a reaction has ended and the resulting product is released, the enzyme returns to its original form, and awaits another substrate to bond with, and the process continues in this way indefinitely.</p><p dir="ltr">(5) There are two main categories of enzymes in our bodies: digestive and systemic. Enzymes that function in the digestive tract act to break down food into its smaller components, which can then be absorbed by the different systems that use them. For instance, the enzyme lipase is what catalyzes the hydrolysis (the process of <strong>breaking down</strong> the chemical bonds in a molecule with water) of fats, or lipids. Without lipases, the proper digestion of lipids would not be possible, and their vital functions in the body (including providing energy storage and structural components of cell walls) would not occur. <strong>26A</strong> Systemic enzymes are found in the blood, tissues, and every cell of the body. <strong>26B</strong> They perform such essential roles as preventing blood clots and inflammation as well as providing powerful antioxidant effects. <strong>26C</strong> When a group of enzymes is unable to function optimally, the results can be catastrophic. <strong>26D</strong></p><p dir="ltr"></p><br /></p></section><section><h3><p>Which of the following is NOT mentioned in paragraph 5 about the two kinds of enzymes in the body?</p></h3><p><p dir="ltr"></p><p dir="ltr"><strong>READING 2</strong></p><p dir="ltr">ENZYMES AND SUBSTRATES</p><p dir="ltr">(1) Although the digestion of meat in the stomach and the conversion of starch into sugars were familiar to scientists as early as the 17th century, the processes by which these took place had not yet been recognized. In 1833, experiments were conducted by Anselme Payen and Jean-Francois Persoz, chemists at a French sugar factory. They discovered the enzyme diastase, which causes the conversion of starch into maltose. Several decades later, Lou is Pasteur realized that the conversion of sugar into alcohol by yeast was a result of a "vital force" within the yeast cells, which he termed "ferments." Since then, advances in technology have led to a more <strong>comprehensive </strong>understanding of the form and function of these specialized proteins, called enzymes, without which life would not be possible.</p><p dir="ltr">(2) Enzymes, which are recognized as the body's metabolic catalysts (a substance that causes a chemical reaction), are responsible for thousands of very specific chemical reactions that transform certain molecules into the substances that support life. These reactions happen with what are termed substrates, molecules that, when they bind with a specific enzyme, form products. <strong>These</strong> are the substances that maintain all the systems in the body. Enzymes are categorized based on the type of reaction they catalyze, and on which substrates they act on. Almost all enzymes, with very few exceptions, have names that end in -ase. Lactase acts on transforming lactose, found naturally in milk, into glucose, also known as blood sugar. Amylases catalyze starches into sugars and proteases catalyze proteins.</p><p dir="ltr">"(3) Enzymes will only bond with certain molecules, and this trait is known as specificity. In 1894, Emil Fischer, Nobel Prize laureate, suggested that enzymes and their substrates functioned according to the "Lock and Key" model. The theory describes the specificity of the reactions between enzymes and substrates like that of a lock that only one key will successfully open. Enzymes and substrates bond at the "active site" of the enzyme, and each enzyme's active site is shaped in a very particular way and this allows it to precisely fit its intended substrate. If a substrate tries to bond with an unintended enzyme, no catalytic action will take place. Although this model effectively explains the specificity of enzymes, it does not make clear how substrates maintain their bond with enzymes during the catalytic reaction. It was proposed by Daniel Koshland in 1958 that the active site of enzymes is composed of flexible amino acid side-chains, and this fact is what allows enzymes to remain bonded with the substrates until the reaction has reached completion and its product can be released.</p><p dir="ltr">"(4) Enzymes not only allow for specificity of reactions, but also for these to happen at the speed necessary for life. Without enzymes, reactions would happen, but at such a slow rate that it would be impossible to <strong>sustain</strong> life. Enzymes speed up the rate of reaction up to millions of times faster than an uncatalyzed reaction. <strong>Consequently, the products necessary for life are formed more quickly, and post-reaction equilibrium (when the opposing forces involved in the reaction have reached a state of balance) is achieved much faster.</strong> Like all catalysts, enzymes are not changed by the reactions they catalyze. Once a reaction has ended and the resulting product is released, the enzyme returns to its original form, and awaits another substrate to bond with, and the process continues in this way indefinitely.</p><p dir="ltr">(5) There are two main categories of enzymes in our bodies: digestive and systemic. Enzymes that function in the digestive tract act to break down food into its smaller components, which can then be absorbed by the different systems that use them. For instance, the enzyme lipase is what catalyzes the hydrolysis (the process of <strong>breaking down</strong> the chemical bonds in a molecule with water) of fats, or lipids. Without lipases, the proper digestion of lipids would not be possible, and their vital functions in the body (including providing energy storage and structural components of cell walls) would not occur. <strong>26A</strong> Systemic enzymes are found in the blood, tissues, and every cell of the body. <strong>26B</strong> They perform such essential roles as preventing blood clots and inflammation as well as providing powerful antioxidant effects. <strong>26C</strong> When a group of enzymes is unable to function optimally, the results can be catastrophic. <strong>26D</strong></p><p dir="ltr"></p><br /></p></section><section><h3><p>Which of the words below best expresses the meaning of the phrase <strong>break down </strong>in paragraph 5?</p></h3><p><p dir="ltr"></p><p dir="ltr"><strong>READING 2</strong></p><p dir="ltr">ENZYMES AND SUBSTRATES</p><p dir="ltr">(1) Although the digestion of meat in the stomach and the conversion of starch into sugars were familiar to scientists as early as the 17th century, the processes by which these took place had not yet been recognized. In 1833, experiments were conducted by Anselme Payen and Jean-Francois Persoz, chemists at a French sugar factory. They discovered the enzyme diastase, which causes the conversion of starch into maltose. Several decades later, Lou is Pasteur realized that the conversion of sugar into alcohol by yeast was a result of a "vital force" within the yeast cells, which he termed "ferments." Since then, advances in technology have led to a more <strong>comprehensive </strong>understanding of the form and function of these specialized proteins, called enzymes, without which life would not be possible.</p><p dir="ltr">(2) Enzymes, which are recognized as the body's metabolic catalysts (a substance that causes a chemical reaction), are responsible for thousands of very specific chemical reactions that transform certain molecules into the substances that support life. These reactions happen with what are termed substrates, molecules that, when they bind with a specific enzyme, form products. <strong>These</strong> are the substances that maintain all the systems in the body. Enzymes are categorized based on the type of reaction they catalyze, and on which substrates they act on. Almost all enzymes, with very few exceptions, have names that end in -ase. Lactase acts on transforming lactose, found naturally in milk, into glucose, also known as blood sugar. Amylases catalyze starches into sugars and proteases catalyze proteins.</p><p dir="ltr">"(3) Enzymes will only bond with certain molecules, and this trait is known as specificity. In 1894, Emil Fischer, Nobel Prize laureate, suggested that enzymes and their substrates functioned according to the "Lock and Key" model. The theory describes the specificity of the reactions between enzymes and substrates like that of a lock that only one key will successfully open. Enzymes and substrates bond at the "active site" of the enzyme, and each enzyme's active site is shaped in a very particular way and this allows it to precisely fit its intended substrate. If a substrate tries to bond with an unintended enzyme, no catalytic action will take place. Although this model effectively explains the specificity of enzymes, it does not make clear how substrates maintain their bond with enzymes during the catalytic reaction. It was proposed by Daniel Koshland in 1958 that the active site of enzymes is composed of flexible amino acid side-chains, and this fact is what allows enzymes to remain bonded with the substrates until the reaction has reached completion and its product can be released.</p><p dir="ltr">"(4) Enzymes not only allow for specificity of reactions, but also for these to happen at the speed necessary for life. Without enzymes, reactions would happen, but at such a slow rate that it would be impossible to <strong>sustain</strong> life. Enzymes speed up the rate of reaction up to millions of times faster than an uncatalyzed reaction. <strong>Consequently, the products necessary for life are formed more quickly, and post-reaction equilibrium (when the opposing forces involved in the reaction have reached a state of balance) is achieved much faster.</strong> Like all catalysts, enzymes are not changed by the reactions they catalyze. Once a reaction has ended and the resulting product is released, the enzyme returns to its original form, and awaits another substrate to bond with, and the process continues in this way indefinitely.</p><p dir="ltr">(5) There are two main categories of enzymes in our bodies: digestive and systemic. Enzymes that function in the digestive tract act to break down food into its smaller components, which can then be absorbed by the different systems that use them. For instance, the enzyme lipase is what catalyzes the hydrolysis (the process of <strong>breaking down</strong> the chemical bonds in a molecule with water) of fats, or lipids. Without lipases, the proper digestion of lipids would not be possible, and their vital functions in the body (including providing energy storage and structural components of cell walls) would not occur. <strong>26A</strong> Systemic enzymes are found in the blood, tissues, and every cell of the body. <strong>26B</strong> They perform such essential roles as preventing blood clots and inflammation as well as providing powerful antioxidant effects. <strong>26C</strong> When a group of enzymes is unable to function optimally, the results can be catastrophic. <strong>26D</strong></p><p dir="ltr"></p><br /></p></section><section><h3><p>Which of the following could <strong><em>optimally</em></strong> in paragraph 5 best be replaced by?</p></h3><p><p dir="ltr"></p><p dir="ltr"><strong>READING 2</strong></p><p dir="ltr">ENZYMES AND SUBSTRATES</p><p dir="ltr">(1) Although the digestion of meat in the stomach and the conversion of starch into sugars were familiar to scientists as early as the 17th century, the processes by which these took place had not yet been recognized. In 1833, experiments were conducted by Anselme Payen and Jean-Francois Persoz, chemists at a French sugar factory. They discovered the enzyme diastase, which causes the conversion of starch into maltose. Several decades later, Lou is Pasteur realized that the conversion of sugar into alcohol by yeast was a result of a "vital force" within the yeast cells, which he termed "ferments." Since then, advances in technology have led to a more <strong>comprehensive </strong>understanding of the form and function of these specialized proteins, called enzymes, without which life would not be possible.</p><p dir="ltr">(2) Enzymes, which are recognized as the body's metabolic catalysts (a substance that causes a chemical reaction), are responsible for thousands of very specific chemical reactions that transform certain molecules into the substances that support life. These reactions happen with what are termed substrates, molecules that, when they bind with a specific enzyme, form products. <strong>These</strong> are the substances that maintain all the systems in the body. Enzymes are categorized based on the type of reaction they catalyze, and on which substrates they act on. Almost all enzymes, with very few exceptions, have names that end in -ase. Lactase acts on transforming lactose, found naturally in milk, into glucose, also known as blood sugar. Amylases catalyze starches into sugars and proteases catalyze proteins.</p><p dir="ltr">"(3) Enzymes will only bond with certain molecules, and this trait is known as specificity. In 1894, Emil Fischer, Nobel Prize laureate, suggested that enzymes and their substrates functioned according to the "Lock and Key" model. The theory describes the specificity of the reactions between enzymes and substrates like that of a lock that only one key will successfully open. Enzymes and substrates bond at the "active site" of the enzyme, and each enzyme's active site is shaped in a very particular way and this allows it to precisely fit its intended substrate. If a substrate tries to bond with an unintended enzyme, no catalytic action will take place. Although this model effectively explains the specificity of enzymes, it does not make clear how substrates maintain their bond with enzymes during the catalytic reaction. It was proposed by Daniel Koshland in 1958 that the active site of enzymes is composed of flexible amino acid side-chains, and this fact is what allows enzymes to remain bonded with the substrates until the reaction has reached completion and its product can be released.</p><p dir="ltr">"(4) Enzymes not only allow for specificity of reactions, but also for these to happen at the speed necessary for life. Without enzymes, reactions would happen, but at such a slow rate that it would be impossible to <strong>sustain</strong> life. Enzymes speed up the rate of reaction up to millions of times faster than an uncatalyzed reaction. <strong>Consequently, the products necessary for life are formed more quickly, and post-reaction equilibrium (when the opposing forces involved in the reaction have reached a state of balance) is achieved much faster.</strong> Like all catalysts, enzymes are not changed by the reactions they catalyze. Once a reaction has ended and the resulting product is released, the enzyme returns to its original form, and awaits another substrate to bond with, and the process continues in this way indefinitely.</p><p dir="ltr">(5) There are two main categories of enzymes in our bodies: digestive and systemic. Enzymes that function in the digestive tract act to break down food into its smaller components, which can then be absorbed by the different systems that use them. For instance, the enzyme lipase is what catalyzes the hydrolysis (the process of <strong>breaking down</strong> the chemical bonds in a molecule with water) of fats, or lipids. Without lipases, the proper digestion of lipids would not be possible, and their vital functions in the body (including providing energy storage and structural components of cell walls) would not occur. <strong>26A</strong> Systemic enzymes are found in the blood, tissues, and every cell of the body. <strong>26B</strong> They perform such essential roles as preventing blood clots and inflammation as well as providing powerful antioxidant effects. <strong>26C</strong> When a group of enzymes is unable to function optimally, the results can be catastrophic. <strong>26D</strong></p><p dir="ltr"></p><br /></p></section><section><h3><p>Read the bold-faced sentence below. Where would the sentence best fit in the passage? <em><strong>Heart disease, stroke, high blood pressure, diabetes and high cholesterol are only a few among the very long list of health implications that develop if enzymatic reactions do not take place properly in the body</strong></em></p></h3><p><p dir="ltr"></p><p dir="ltr"><strong>READING 2</strong></p><p dir="ltr">ENZYMES AND SUBSTRATES</p><p dir="ltr">(1) Although the digestion of meat in the stomach and the conversion of starch into sugars were familiar to scientists as early as the 17th century, the processes by which these took place had not yet been recognized. In 1833, experiments were conducted by Anselme Payen and Jean-Francois Persoz, chemists at a French sugar factory. They discovered the enzyme diastase, which causes the conversion of starch into maltose. Several decades later, Lou is Pasteur realized that the conversion of sugar into alcohol by yeast was a result of a "vital force" within the yeast cells, which he termed "ferments." Since then, advances in technology have led to a more <strong>comprehensive </strong>understanding of the form and function of these specialized proteins, called enzymes, without which life would not be possible.</p><p dir="ltr">(2) Enzymes, which are recognized as the body's metabolic catalysts (a substance that causes a chemical reaction), are responsible for thousands of very specific chemical reactions that transform certain molecules into the substances that support life. These reactions happen with what are termed substrates, molecules that, when they bind with a specific enzyme, form products. <strong>These</strong> are the substances that maintain all the systems in the body. Enzymes are categorized based on the type of reaction they catalyze, and on which substrates they act on. Almost all enzymes, with very few exceptions, have names that end in -ase. Lactase acts on transforming lactose, found naturally in milk, into glucose, also known as blood sugar. Amylases catalyze starches into sugars and proteases catalyze proteins.</p><p dir="ltr">"(3) Enzymes will only bond with certain molecules, and this trait is known as specificity. In 1894, Emil Fischer, Nobel Prize laureate, suggested that enzymes and their substrates functioned according to the "Lock and Key" model. The theory describes the specificity of the reactions between enzymes and substrates like that of a lock that only one key will successfully open. Enzymes and substrates bond at the "active site" of the enzyme, and each enzyme's active site is shaped in a very particular way and this allows it to precisely fit its intended substrate. If a substrate tries to bond with an unintended enzyme, no catalytic action will take place. Although this model effectively explains the specificity of enzymes, it does not make clear how substrates maintain their bond with enzymes during the catalytic reaction. It was proposed by Daniel Koshland in 1958 that the active site of enzymes is composed of flexible amino acid side-chains, and this fact is what allows enzymes to remain bonded with the substrates until the reaction has reached completion and its product can be released.</p><p dir="ltr">"(4) Enzymes not only allow for specificity of reactions, but also for these to happen at the speed necessary for life. Without enzymes, reactions would happen, but at such a slow rate that it would be impossible to <strong>sustain</strong> life. Enzymes speed up the rate of reaction up to millions of times faster than an uncatalyzed reaction. <strong>Consequently, the products necessary for life are formed more quickly, and post-reaction equilibrium (when the opposing forces involved in the reaction have reached a state of balance) is achieved much faster.</strong> Like all catalysts, enzymes are not changed by the reactions they catalyze. Once a reaction has ended and the resulting product is released, the enzyme returns to its original form, and awaits another substrate to bond with, and the process continues in this way indefinitely.</p><p dir="ltr">(5) There are two main categories of enzymes in our bodies: digestive and systemic. Enzymes that function in the digestive tract act to break down food into its smaller components, which can then be absorbed by the different systems that use them. For instance, the enzyme lipase is what catalyzes the hydrolysis (the process of <strong>breaking down</strong> the chemical bonds in a molecule with water) of fats, or lipids. Without lipases, the proper digestion of lipids would not be possible, and their vital functions in the body (including providing energy storage and structural components of cell walls) would not occur. <strong>26A</strong> Systemic enzymes are found in the blood, tissues, and every cell of the body. <strong>26B</strong> They perform such essential roles as preventing blood clots and inflammation as well as providing powerful antioxidant effects. <strong>26C</strong> When a group of enzymes is unable to function optimally, the results can be catastrophic. <strong>26D</strong></p><p dir="ltr"></p><br /></p></section><section><h3><p>what do the speakers mainly discuss?</p></h3><p>Listening 1 for number 26-30. The audio only appears in number 26, please listen carefully.</p></section><section><h3><p>what reason does the professor give for wanting to meet with the student?</p></h3></section><section><h3><p>what does the students like about Pablo Neruda's poem in the book Elemental Odes?</p></h3></section><section><h3></h3><p>why does the student mention the meter called iambic pentrameter?</p></section><section><h3><p>what does the professor mean when she says this:</p></h3></section><section><h3><p>what is the purpose of the lecture?</p></h3><p>Listening II for questions number 31-36.</p></section><section><h3><p>why does the professor mention books and a map?</p></h3></section><section><h3><p>according to the professor, why did artist like James Peale adopt a scientific approach to still-life painting?</p></h3></section><section><h3><p>why does the professor tell the story about his own painting of some vegetables?</p></h3></section><section><h3><p>what point does the professor make about negative space in still-life painting?</p></h3></section><section><h3><p>why does the professor say this:</p></h3></section><section><h3><p>what is the lecture mainly about?</p></h3><p>Listening III for questions number 37-42.</p></section><section><h3><p>why does the professor mention ants and rodents competing for good?</p></h3></section><section><h3><p>according to the professor, how do trees contribute to the sucessful spawning of salmon? select two answers</p></h3></section><section><h3><p>what point does the professor make about bears carrying salmon away from streams?</p></h3></section><section><h3><p>what does the professor imply about overfishing?</p></h3></section><section><h3><p>why does one of the students say this:</p></h3></section><section><h3><p>why does the woman go to talk to the man?</p></h3><p>Listening IV for questions number 43-47.</p></section><section><h3><p>what is the main reason that the woman cannot display her ceramic bowls in the campus store?</p></h3></section><section><h3><p>According to the conversation, what is a reason that the woman wants to sell her bowls?</p></h3></section><section><h3><p>what is the woman's attitude toward selling items at Eporium?</p></h3></section><section><h3><p>what concerns does the woman initially express about selling items at the craft fair? select TWO answers</p></h3></section><section><h3><p>what aspects of snowflakes does the professor mainly discuss?</p></h3><p>Listening V for questions number 48-53.</p></section><section><h3><p>what does the professor say about the role of water vapor in snowflake formation?</p></h3></section><section><h3><p>what factor helps explain why no two snowflakes are alike?</p></h3></section><section><h3><p>how do molecules in the quasi-liquid layer differ from those in other parts of snowflakes?</p></h3></section><section><h3><p>what does the professor imply about ice crystals with a large number of branches?</p></h3></section><section><h3><p>what can be inferred about the professor when he says this</p></h3></section><section><h2></h2></section><section><h3></h3></section>
