搜档网
当前位置:搜档网 › 新sat证据题练习

新sat证据题练习

新sat证据题练习
新sat证据题练习

证据题练习(要求画出题目关键词以及如何跟正确选项对应)

1.the narrator indicates that many previous explorers seeking the North Pore have

A.Perished in the attempt

B.Made surprising discoveries

C.Failed to determine its location

D.Had different motivations than his own

2.which choice provides the best evidence for the answer to the previous question?

A.nobody has succeeded in this thing, and many have died.

B.All this i understand, as i understand each detail of the technique by which this is carried out.

C. The Danish ministers have declared from their pulpits that participation in polar expedition is beneficial to the soul’s eternal well-being, or so i read in a newspaper.

D.Behind us,perhaps forever,lie the Cities of Men with their teacups and their brass bedsteads.

3.according to the passage, which choice best describes the current financial situation in many major American cities?

A.Expected tax increases due to demand for public works.

B.Economic hardship due to promises made in the past years.

C.Greater overall prosperity due to an increased inner-city tax base.

D.Insufficient revenues due to a decrease in manufacturing.

4.Evidence for the previous question?

A.America’s major cities face enormous fiscal problems,many of them the result of the public pension obligations they incurred in the more prosperous years of the past two decades.

B.How the cities are going to solve this problems, i do not know.

C.What i do know is that if fiscal crisis were going to drive affluent professionals out of central cities, it would have done so by now.

D.The truth is that we are living at a moment in which the massive outward migration of the affluent that characterized the second half of the twentieth century is coming to an end.

5.The passage implies that american cities in 1974

A.Were witnessing the flight of minority populations to suburbs.

B.Had begun to lose their manufacturing sectors.

C.Had a traditional four-zone structure.

D.Were already experiencing demographic.

6.Evidence for previous question?

A.much of our perspective on the process of metropolitan settlement dates,whether we realize it or not, from a paper written in 1925 by the University of Chicago sociologist Burgess.

B.It was Burgess who defined four urban/suburban zones of settlement

C. Burgess was right about the urban America of 1925;he was right about the urban America of 1974. Virtually every city in the country had a downtown, where the commercial life of the metropolis was conducted;it had a factory district just beyond;it had districts of working-class residences just beyond that;and it had residential suburbs for the wealthy and the upper middle class at the far end of the continuum.

D.As a family moved up the economic ladder, it also moved outward from crowded working-class districts to more spacious apartments and, eventually, to a suburban home.

7.What does the author suggest about the transgenic studies done in the 1980s and 1990s?

A.They were limited by the expensive nature of animal research.

B.They were not expected to yield products ready for human use.

C.They were completed when an anticoagulant compound was identified.

D.They focused only on the molecular properties of cows,goats, and sheep.

8, evidence for the previous question?

A.The trouble is that it’s difficult and expensive to make these compounds on an industrial scale, and as a result, patients can face shortages of the medicines they need.

B.If they put the gene just in the right place,under the control of the right molecular switch,maybe they could engineer animals that produced healing human proteins in their milk.

C.Throughout the 1980s and 1990s, studies..............at first,this work was merely gee-whiz,scientific geekery, lab-bound thought experiments come true.

D.That all changed with ATryn, a drug produced by the Massachusetts firm GTC Biotherapeutics. ATryn is antithrombin, an anticoagulant that can be used to prevent life-threatening blood clots.

9.Which of the following is true of antithrombin?

A.It reduces compounds that lead to blood clots.

B.It stems from a genetic mutation that is rare in humans.

C.It is a sequence of DNA as a promoter.

D.It occurs naturally in goats’ mammary glands.

10.Evidence for the previous question?

A.Many of the proteins that our cells crank out naturally make for good medicine.our bodies’own enzymes,hormones,clotting factors, and antibodies are commonly used to treat cancer,diabetes,autoimmune diseases.

B.Antithrombin....the compound........It acts as a molecular bouncer,sidling up to clot-forming compounds and escorting them out of the bloodstream.

C.But as many as 1 in 2000 Americans are born with a genetic mutation that prevents them from making antithrombin.

D.The researchers paired the antithrombin gene with a promoter (which is a sequence of DNA that controls gene activity ) that is normally active in the goats’mammary glands during milk production.

11.How would Paine most likely respond to Burke’s statement in “as the ends of such a partnership cannot be obtained in many generations, it becomes a partnership not only between those who are living, but between those who are living,those who are dead, and those who are to be born...

A.He would assert that the notion of a partnership across generations is less plausible to people of his ear than it was to people in the past.

B.He would argue there are no politically meaningful links between the dead, the living, and the unborn.

C.He would question the possibility that significant changes to a political system could be accomplished within a single generation.

D.He would point out that we cannot know what judgments the dead would make about

contemporary issues.

12.Evidence...、

A.every age and genenration must be as free to act for itself,in all cases,as the ages and

generations which preceded it.

B.The vanity and presumption of governing beyond the grave,is the most rediculous and

insolent of all tyrannies.

C.It is the living,and not the dead,that are to be accommodated.

D.(Those who have quitted the world, and those who are not yet arrived at it, are as remote

from each other, as the utmost stretch of moral imagination can conceive.)What possible obligation,then,can exist between them;what rule or principle can be laid down,that two nonentities,the one out of existence, and the other not in, and who never can meet in this world,that the one should control the other to the end of time?

13.Where does the author indicate the medieval volcanic eruption most likely was located?

a.Near the equator,in Indonesia

b.In the arctic region

c.In the antarctic region

d.Near the equator, in Ecuador

14.Evidence for the previous question?

a.About 750years ago, a powerful volcano erupted somewhere on earth,kicking off a

centuries-long cold snap known as the Little Ice Age.

b.Such a sudden onset pointed to a huge volcanic eruption injecting sulfur into the

stratosphere and starting the cooling.

c.The volum of ash deposited, and the estimated height of the eruption’s magnitude at a

minimum of 7 on the volcanic explosivity index(which has a scale of 1-8)-making it one of the largest known in the Holocene.

d.It is no a total surprise that an Indonesian volcano might be the source of the eruption, Miller

says. “an equatorial eruption is more consistent with the apparent climate impacts.”

15.Which choice best supports the claim that Quilotoa was not responsible for the Little Ice Age?

a.idenifying the volcano responsible has been tricky.

b.Such a sudden onset pointed to a huge volcanic eruption injecting sulfur into the

stratosphere and starting the cooling.

c.The researchers then began to reconduct the formation of the large,800-meter-deep

caldera(a basin-shaped volcanic crater) that now sits atop the volcano.

d.(another possible candidate-both in terms of timing and geographical location-is

Quilotoa,estimated to have last erupted between 1147 and 1320 C.E.)But when Lavigne’s team examined sahrds of volcanic glass from this volcano, they found that they didn’t match the chemical composition of the glass is much closer match.

AABAC CBCAB BDADD

新SAT阅读真题四

新SAT阅读真题四 Exercise 4 This passage is excerpted from Louisa May Alcott, Rose in Bloom, originally published in 1876. Three young men stood together on a wharf one bright October day awaiting the arrival of an ocean steamer with an impatience which found a vent in lively skirmishes with a small lad, who pervaded the premises like a will-o'-the-wisp and afforded much amusement to the other groups assembled there. "They are the Campbells, waiting for their cousin, who has been abroad several years with her uncle, the doctor," whispered one lady to another as the handsomest of the young men touched his hat to her as he passed, lugging the boy, whom he had just rescued from a little expedition down among the piles."Which is that?" asked the stranger. "Prince Charlie, as he's called a ?ne fellow, the most promising of the seven, but a little fast, people say," answered the ?rst speaker with a shake of the head. "Are the others his brothers?""No, cousins. The elder is Archie, a most exemplary young man. He has just gone into business with the merchant uncle and bids fair to be an honor to his family. The other, with the eyeglasses and no gloves, is Mac, the odd one, just out of college." "And the boy?" "Oh, he is Jamie, the youngest brother of Archibald, and the pet of the whole family. Mercy on us he'll be in if they don't hold on to him!"

新SAT阅读真题一

新SAT阅读真题一 如今同学们参加SAT考试,都是SAT改革之后的新SAT考试。在改革之后,SAT阅读部分也有了相应的变化。同学们要想充分的备考新SAT阅读考试,还是需要更多的来练习真题。 Exercise 1 This passage is excerpted from Jane Austen, Northanger Abbey, originally published in 1803. Mrs. Allen was so long in dressing that they did not enter the ballroom till late. As for Mr. Allen, he repaired directly to the card-room. With more care for the safety of her new gown than for the comfort of her protegee, Mrs. Allen made her way through the throng of men by the door, as swiftly as the necessary caution would allow; Catherine, however, kept close at her side, and linked her arm too ?rmly within her friend's to be torn asunder by any common effort of a struggling assembly. Still they moved on—something better was yet in view; and by a continued exertion of strength and ingenuity they found themselves at last in the passage behind the highest bench. It was a splendid sight, and she began, for the ?rst time that evening, to feel herself at a ball: she longed to dance, but she had not an acquaintance in the room. Catherine began to feel something of disappointment—she was tired of being continually pressed against by people, the generality of whose faces possessed nothing to interest, and with all of whom she was so wholly unacquainted that she could not relieve the irksomeness of

(完整版)SATog5阅读真题解析

SAT test 5 1.For a long time, most doctors maintained that taking massive doses of vitamins was relatively harmless; now, however, some are warning that excessive dosages can be _________. (A) healthy adj. 健康的 (B) expensive adj. 昂贵的 (C) wasteful adj. 浪费的 (D) toxic adj. 有毒的 (E) inane adj. 愚蠢的 解析:D,在很长的一段时间里,大多数医生认为用大量的维他命是无害的;不过现在有些人警告过量食用会----。这里however表示转折与前面的harmless是相反的意思。 2. In Jamaica Kincaid's novel Lucy, the west Indian heroine _________ her employers' world, critically examining its assumptions and values. (A) idealizes v. 理想化 (B) avoids v. 避开 (C) beautifies v. 美化 (D) scrutinizes v. 仔细检查 (E) excludes v. 排除, 解析:E,在牙买加金彩的小说露西,这个西印度群岛英雄----她的雇主的世界,精细的审视他的猜测和价值。这个句子中前后两句意思是一致的,没有转折词,所以空格所需的东西与examining是同义词,所以D。 3.The frequent name changes that the country has undergone _________ the political turbulence that has attended its recent history. (A) argue against v. 真钞,辩论 (B) contrast with v. 对比,差异 (C) testify to v. 证明 (D) jeopardize v. 危及

SAT og 5阅读真题解析

SAT test 5 1. For a long time, most doctors maintained that taking massive doses of vitamins was relatively harmless; now, however, some are warning that excessive dosages can be _________. (A) healthy adj. 健康的 (B) expensive adj. 昂贵的 (C) wasteful adj. 浪费的 (D) toxic adj. 有毒的 (E) inane adj. 愚蠢的 解析:D,在很长的一段时间里,大多数医生认为用大量的维他命是无害的;不过现在有些人警告过量食用会----。这里however表示转折与前面的harmless是相反的意思。 2. In Jamaica Kincaid's novel Lucy, the west Indian heroine _________ her employers' world, critically examining its assumptions and values. (A) idealizes v. 理想化 (B) avoids v. 避开 (C) beautifies v. 美化 (D) scrutinizes v. 仔细检查 (E) excludes v. 排除,

解析:E,在牙买加金彩的小说露西,这个西印度群岛英雄----她的雇主的世界,精细的审视他的猜测和价值。这个句子中前后两句意思是一致的,没有转折词,所以空格所需的东西与examining是同义词,所以D。 frequent name changes that the country has undergone _________ the political turbulence that has attended its recent history. (A) argue against v. 真钞,辩论 (B) contrast with v. 对比,差异 (C) testify to v. 证明 (D) jeopardize v. 危及 (E) sustain v. 支撑 解析:C,这个国家经历了频繁的国名变更---这个国家的近点史上的政治动乱。从句意可以看后句和前句是因果关系,前面证明了后面。 , clamlike bivalves of prehistoric times, were one of the most _________ forms of life on the Earth: more than 30,000 species have been _________ from fossil records. (A) plentiful adj. 丰富的...subtracted v. 减去 (B) ornate adj. 华丽的...retrieved v. 重新取回 (C) multifarious adj. 多方面的...catalogued v. 登记分类 (D) scarce adj. 缺乏的,罕见的...extracted v. 萃取的 (E) anachronistic adj. 时代错误的...extrapolated v. 推算,推断

SAT阅读测试题1

Questions 10-14 are based on the following passage. This passage is from the preface to a 1997 book by a United States journalist detailing a disagreement between doctors and family members about a child's medical treatment at a hospital in California. Under my desk I keep a large carton of cassette tapes. Though they have all been transcribed, I still like to listen to them from time to time, Some are quiet and easily understood. They are filled with the voices of American doctors, interrupted occasionally by the clink of a coffee cup or beep of a pager. The rest—more than half of them—are very noisy. They are filled with the voices of the Lees family, Hmong refugees from Laos who came to the United States in 1980. Against a background of babies crying, children playing, doors slamming, dishes clattering, a television yammering, and an air conditioner wheezing, I can hear the mother's voice, by turns breathy, nasal, gargly, or humlike as it slides up and down the Hmong language's eight tones; the father's voice, louder, slower, more vehement; and my interpreter's voice, mediating in Hmong and English, low and deferential in each. The hubbub summons sense-memories: the coolness of the red metal folding chair, reserved for guests, that was always set up when I arrived in the apartment; the shadows cast by the amulet that hung from the ceiling and swung in the breeze on its length of grocer's twine; the tastes of Hmong food. I sat on the Lees' red chair for the first lime on May 19, 1988. Earlier that spring I had come to Merced, California, because I had heard that there were some misunderstandings at the county hospital between its Hmong patients and medical staff. One doctor called them "collisions," which made it sound as if two different kinds of people had rammed into each other, head on, to the accompaniment of squealing brakes and breaking glass. As it turned out, the encounters were messy but rarely frontal. Both sides were wounded, but neither side seemed to know what had hit it or how to avoid another crash. I have always felt that the action most worth watching occurs not at the center of things but where edges meet. I like shorelines, weather fronts, international borders. These places have interesting frictions and incongruities, and often, if you stand at the point of tangency, you can see both sides better than if you were in the middle of either one. This is especially true when the apposition is cultural. When I first came to Merced, I hoped that the culture of American medicine, about which I knew a little, and the culture of the Hmong, about which I knew nothing, would somehow illuminate each other if I could position myself between the two and manage not to get caught in the crossfire. But after getting to know the Lees family and their daughter's doctors and realizing how hard it was to blame anyone, I stopped analyzing the situation in such linear terms. Now, when I play the tapes late at night, I imagine what they would sound like if I could splice them together, so the voices of the Hmong and those of the American doctors could be heard on a single tape, speaking a common language. 10. In line 17, "summons" most nearly means (A) sends for (B) calls forth (C) requests (D) orders (E) convenes 11. It can be inferred from lines 27-33 that "collisions" was NOT an apt description because the (A) clash between Hmong patients and medical staff was indirect and baffling (B) Hmong patients and the medical staff were not significantly affected by the encounters (C) medical staff was not responsible for the dissatisfaction of the Hmong patients (D) misunderstandings between the Hmong patients and the medical staff were easy to resolve (E) disagreement reached beyond particular individuals to the community at large

SAT真题阅读答案

第一套:0708 SECTION4:1-5ECBEC 6-10BDBDB 11-15AEABA 16-20BEAEC 21-23DEC SECTION6:1-5AADCB 6-10CBACB 11-15EAEBC 16-20ECDAD 21-25BBDAB SECTION9:1-5EBCCD 6-10ABDEC 11-15CCABA 16-19DCCE 第二套:0809 SECTION3:1-5EABAA 6-10EECCA 11-15DCEDC 16-20BEADC 21-24EEEB SECTION7:1-5DCABC 6-10CEEDB 11-15DBCDE 16-20ADEDA 21-24BACB SECTION9:1-5ABBDD 6-10DBAEB 11-15BDCCC 16-19DECE 第三套:0601 SECTION4:1-5DDACB 6-10EBCAB 11-15BACEC 16-20CDDEE 21-25ADBE

SECTION7:1-5ECAED 6-10EBACC 11-15AEABB 16-20DCEAB 21-24ABDB SECTION9:1-5BDEDE 6-10DACDD 11-15CBBAE 16-19DCCE 第四套:0605 SECTION3:1-5EEBED 6-10DEBDA 11-15EBDED 16-20ADBAC 21-24CBEC SECTION5:1-5CADCB 6-10EACBB 11-15ACEAE 16-20ECBCC 21-24DEEA SECTION8:1-5ACBDD 6-10EADEC 11-15AEBCC 16-19BEED 第五套:0610 SECTION2:1-5ABADC 6-10DBCAD 11-15BCEEB 16-20CAEBA 21-24DEEC SECTION5:1-5CBCAD 6-10BDCAB 11-15ECDDE 16-20EBEAD 21-24ACEE SECTION9:1-5BCBEB 6-10DCCEE

新SAT阅读真题原文解析

新SAT阅读真题原文解析 新SAT阅读真题原文来啦~和小编一起来看看SAT阅读都考了哪些内容吧! Unfortunately or fortunately, Nawab hadmarried early in life a sweet woman of unsurpassed fertility, whom he adored,and she proceeded to bear him children spaced, if not less than nine monthsapart, then not that much more. And all daughters, one after another afteranother, until finally the looked-for son arrived, leaving Nawab with acomplete set of twelve girls, ranging from toddler to age eleven, and one oddpiece. If he had been governor of the Punjab, their dowries would have beggaredhim. For an electrician and mechanic, no matter how light-fingered, thereseemed no question of marrying them all off. No moneylender in his right mindwould, at any rate of interest, advance a sufficient sum to buy the necessaryitems for each daughter: beds, a dresser, trunks, electric fans, dishes, sixsuits of clothes for the groom, six for the bride, perhaps a television, and onand on and on. Another man might have thrown up hishands—but not Nawabdin. The daughters acted as a spur to his genius, and helooked with satisfaction in the mirror each morning at the face of a warriorgoing out to do battle. Nawa b of course knew that he must proliferate hissources of revenue—the salary he received from K. K. Harouni for tending thetube wells would not even begin to suffice. He set up a one-room flour mill,run off a condemned electri c motor—condemne d by him. H e tried his hand atfish-farming in a pond at the edge o f one of his master’

SAT真题

SAT真题 做SAT免费的手机APP软件,随时做题随时测分,豌豆荚、应用汇、豌豆荚等应用商店搜Satonline就可下载啦或者去官网Satonline下载 1. Some fans feel that sports events are ______ only when the competitors are of equal ability, making the outcome of the game ______. A. successf ul…assured B. boring…questionable C. dull…foreseen D. interesting…predictable E. exciting…uncertain 2. Alfred Schnittke's musical compositions are ______: phrases are clipped, broken into sections, and split apart by long rests. A. garnished B. improvisational C. fragmented D. cautious E. uniform 3. The consumer advocate claimed that while drug manufacturers ______ the supposed advantages of their proprietary brands, generic versions of the same medications are often equally ______. A. tout…efficacious B. research…innocuous C. market…prohibitive D. laud…counterproductive E. extract…prescriptive 4. Latoya's _____ is shown by her ability to be ______: she can see her own faults more clearly than anyone else can. A. perceptiveness…self-centered B. objectivit y…restrictive C. cynicism…self-destructive D. open-mindedness…complacent E. insightfulness…self-critical 5. The bearded dragon lizard is a voracious eater, so ______ that it will consume as many insects as possible. A. abstemious

SAT阅读真题及答案解析(二)

SAT阅读真题及答案解析(二) SAT考试真题是很重要的备考资料,那么,很早以前的真题资料还有参考性吗?其实大家可以先以最近真题为主,以前的真题资料为辅进行练习。下面文都国际小编为大家整理了一篇SAT阅读真题及答案解析,供大家参考。 In the wake of the Industrial Revolution, when mass production became the pride and joy of nineteenth-century entrepreneurs, a fast-growing middle class reveled in the luxury of consumer goods, including jewelry, made available at economical prices. Prosperous segments of the population wanted to demonstrate their affluence, a development that provided a powerful stimulus to the jewelry industry in both Europe and the United States. 在工业革命苏醒之际,大规模生产变成了十九世纪企业家的骄傲和自豪。快速发展的中产阶级让奢侈品变成了大众消费品。百姓中富裕的人们想要显示自己的富裕。而这一因素的存在也快速激励了美国及欧洲的珠宝行业。 In this avalanche of mass production, many artists and artisans of the Arts and Crafts movement felt that the human touch, respect for materials, and the satisfaction of a fine finish were being lost. Jewelry, like other articles, was becoming impersonal, carelessly constructed, unimaginatively designed. Though labeled romantic and idealistic, some artists sought to produce individually conceived and executed pieces in workshop situations similar to those of medieval guilds. They wanted to produce, handmade jewelry from less-expensive materials for the general public, yet with the same care and commitment a court jeweler might apply to work for aristocratic clientele. In medieval times there had been artisans in towns and villages, working for ordinary people on a one-to-one basis; the adherents of the movement felt there was an urgency to return to this special relationship. It was considered particularly important that artists be involved to ensure the production of more meaningful objects, whether they be pottery, furniture, or, especially,

新SAT阅读真题二

新SAT阅读真题二 Exercise 2 This passage is excerpted from L.M. Montgomery, “The Gossip of Valley View,” originally published in 1910. It was the ?rst of April, and Julius Barrett, aged fourteen, perched on his father's gatepost, watched ruefully the low descending sun, and counted that day lost. He had not succeeded in "fooling" a single person, although he had tried repeatedly. One and all, old and young, of his intended victims had been too wary for Julius. Hence, Julius was disgusted and ready for anything in the way of a stratagem or a spoil. The Barrett gatepost topped the highest hill in Valley View. Julius could see the entire settlement, from "Young" Thomas Everett's farm, a mile to the west, to Adelia Williams's weather-grey little house on a moonrise slope to the east. He was gazing moodily down the muddy road when Dan Chester, homeward bound from the post of?ce, came riding sloppily along on his grey mare and pulled up by the Barrett gate to hand a paper to Julius. Dan was a young man who took life and himself very seriously. He seldom smiled, never joked, and had a Washingtonian reputation for veracity. Dan had never told a conscious falsehood in his life; he never even exaggerated. Julius, beholding Dan's solemn face, was seized with a perfectly irresistible desire to "fool" him. At the same moment his eye caught the dazzling re?ection of the setting sun on the windows of Adelia Williams's house, and he had an inspiration little short of diabolical. "Have you heard the news, Dan?" he asked. "No, what is it?" asked Dan.

可汗学院新SAT阅读真题下载(68篇)

可汗学院新SAT阅读真题下载 到目前为止,新版SAT可汗学院官方不断放出更多真题,已经放出了68篇阅读,具体如下:Level 2 22篇,Level 3 21篇,Level 4 17篇,8篇Diagnostic Quiz,共68篇阅读! 想要下载可汗学院68篇阅读真题的同学,请移步:https://www.sodocs.net/doc/298652879.html,/sat/news/603917.html Level 2Science篇1 Passage adapted from Nikhil Swaminathan, "Eat (Less) to Live (Longer)," ?2007 by Scientific American. Scientists have known for more than 70 years that the one surefire way to extend the lives of animals was to cut calories by an average of 30 to 40 percent. The question was: Why? Now a new study begins to unravel the mystery and the mechanism by which reducing food intake protects cells against aging and age-related diseases. Researchers report in the journal Cell that the phenomenon is likely linked to two enzymes—SIRT3 and SIRT4—in mitochondria (the cell's powerhouse that, among other tasks, converts nutrients to energy). They found that a cascade of reactions triggered by lower caloric intake raises the levels of these enzymes, leading to an increase in the strength and efficiency of the cellular batteries. By invigorating the mitochondria, SIRT3 and SIRT4 extend the life of cells, by preventing flagging mitochondria from developing tiny holes (or pores) in their membranes that allow proteins that trigger apoptosis, or cell death, to seep out into the rest of the cell. "We didn't expect that the most important part of this pathway was in the mitochondria," says David Sinclair, an assistant professor of pathology at Harvard Medical School and a study co-author. "We think that we've possibly found regulators of aging." In 2003 Sinclair's lab published a paper in Nature that described the discovery of a gene that switched on in the yeast cell in response to calorie restriction, which Sinclair calls a "master regulator in aging." Since then, his team has been searching for an analogous gene that plays a similar role in the mammalian cell. The researchers determined from cultures of human embryonic kidney cells that lower caloric intake sends a signal that activates a gene inside cells that codes for the enzyme NAMPT (nicotinamide phosphoribosyltransferase). The two- to four-fold surge in NAMPT in turn triggers the production of a molecule called NAD (nicotinamide adenine dinucleotide), which plays a key role in cellular metabolism and signaling. The uptick in NAD levels activates the SIRT3 and SIRT4 genes, increasing levels of their corresponding SIRT3 and SIRT4 enzymes, which then flood the interior of the mitochondria. Sinclair says he's not sure exactly how SIRT3 and SIRT4 beef up the mitochondria's energy output, but that events leading to cell death are at the very least delayed when there are vast quantities of the enzymes. SIRT3 and SIRT4 are part of a family called sirtuins (SIRT1, which helps extend cell life by modulating the number of repair proteins fixing DNA damage both inside and outside the cell's nucleus, is also a member). SIRT is short for sir-2

相关主题