Why elephants rarely get cancer is a mystery that has confused scientists for decades. A study led by researchers at Huntsman Cancer Institute (HCI), at the University of Utah and Arizona State University may have found the answer.
According to the results, elephants have 38 additional modified copies of a gene that encodes p53, a definite tumor suppressor, as compared to humans, who have only two. Further, elephants may have a more powerful mechanism for killing damaged cells that are at risk for becoming cancerous. In isolated elephant cells, this activity is doubled compared to healthy human cells, and five times that of cells from patients with Li-Fraumeni Syndrome, who have only one working copy of p53 and more than a 90 percent lifetime cancer risk in children and adults. The results suggest extra p53 could explain elephants’ increased resistance to cancer.
“Nature has already figured out how to prevent cancer. It’s up to us to learn how different animals overcome the problem so we can adapt those strategies to prevent cancer in people,” says co-senior author Joshua Schiffman, M.D., pediatric oncologist (儿科肿瘤医生) at Huntsman Cancer Institute, University of Utah School of Medicine.
But Prof Mel Greaves, from the Institute of Cancer Research in London, says we should focus on why humans have such high levels of cancer. He pointed to the rise of unhealthy, cancer-causing behaviors, such as obesity and sunbathing. “You’ve never seen an elephant smoke!” he added.
According to Schiffman, elephants have long been considered a walking problem. Because they have 100 times as many cells as people, they should be 100 times more likely to have a cell slip into a cancerous state and cause the disease over their long life span of 50 to 70 years. And yet analysis of a large database of elephant deaths estimates a cancer death rate of less than 5 percent compared to 11 to 25 percent in people.
1.Why are elephants less likely to get cancer than humans?
A.Elephants are bigger than humans.
B.Elephants have more p53 genes and mechanism killing damaged cells.
C.Elephants are not as clever as humans in walking.
D.Elephants eat more than humans.
2.Which of the following can be the equivalent of the underlined word “suppressor”?
A.multiplier B.complex C.restrainer D.coordinator
3.What’s Prof Mel Greaves’ attitude towards the discovery?
A.Doubtful. B.Neutral. C.Critical. D.Favorable.
4.What can we infer from the last paragraph?
A.Elephants have longer life than people.
B.There is no chance that elephants die from cancer.
C.The rate of elephants dying from cancer is increasing.
D.It was thought theoretically that elephants could get cancer more easily.
高三英语阅读理解中等难度题
Why elephants rarely get cancer is a mystery that has confused scientists for decades. A study led by researchers at Huntsman Cancer Institute (HCI), at the University of Utah and Arizona State University may have found the answer.
According to the results, elephants have 38 additional modified copies of a gene that encodes p53, a definite tumor suppressor, as compared to humans, who have only two. Further, elephants may have a more powerful mechanism for killing damaged cells that are at risk for becoming cancerous. In isolated elephant cells, this activity is doubled compared to healthy human cells, and five times that of cells from patients with Li-Fraumeni Syndrome, who have only one working copy of p53 and more than a 90 percent lifetime cancer risk in children and adults. The results suggest extra p53 could explain elephants’ increased resistance to cancer.
“Nature has already figured out how to prevent cancer. It’s up to us to learn how different animals overcome the problem so we can adapt those strategies to prevent cancer in people,” says co-senior author Joshua Schiffman, M.D., pediatric oncologist (儿科肿瘤医生) at Huntsman Cancer Institute, University of Utah School of Medicine.
But Prof Mel Greaves, from the Institute of Cancer Research in London, says we should focus on why humans have such high levels of cancer. He pointed to the rise of unhealthy, cancer-causing behaviors, such as obesity and sunbathing. “You’ve never seen an elephant smoke!” he added.
According to Schiffman, elephants have long been considered a walking problem. Because they have 100 times as many cells as people, they should be 100 times more likely to have a cell slip into a cancerous state and cause the disease over their long life span of 50 to 70 years. And yet analysis of a large database of elephant deaths estimates a cancer death rate of less than 5 percent compared to 11 to 25 percent in people.
1.Why are elephants less likely to get cancer than humans?
A.Elephants are bigger than humans.
B.Elephants have more p53 genes and mechanism killing damaged cells.
C.Elephants are not as clever as humans in walking.
D.Elephants eat more than humans.
2.Which of the following can be the equivalent of the underlined word “suppressor”?
A.multiplier B.complex C.restrainer D.coordinator
3.What’s Prof Mel Greaves’ attitude towards the discovery?
A.Doubtful. B.Neutral. C.Critical. D.Favorable.
4.What can we infer from the last paragraph?
A.Elephants have longer life than people.
B.There is no chance that elephants die from cancer.
C.The rate of elephants dying from cancer is increasing.
D.It was thought theoretically that elephants could get cancer more easily.
高三英语阅读理解中等难度题查看答案及解析
Less than 5 percent of elephants die from cancer, and researchers may have finally figured out why.
According to a study from The University of Chicago, elephants produce "zombie genes" (僵尸基因)that can help protect the animal from cancer.
Here's how it works: Humans and other animals carry one copy of a " master tumor suppressor" Gene(主肿瘤抑制基因). Elephants have 20 copies. Scientists found that gene can cause a "zombie gene" to come back to life with a new purpose: killing cells in damaged DNA.
This is beneficial. because it acts in response to genetic mistakes, errors made when the DNA is being repaired, said Vincent Lynch, an assistant professor of human genetics at the University of Chicago and the study's lead author, in a statement. " Getting rid of that cell can prevent a subsequent cancer. "
Scientists say the gene also helps elephants enjoy long lives. They likely emerged roughly 25 to 30 million years ago, when small - sized ancestors of modern elephants grew bigger, Lynch said.
Researchers want to conduct more studies to find out exactly how the genes in elephants kill off cells in damaged DNA. That could help humans: Studying how animals' bodies fight off cancer could lead to strategies to treat people. An estimated 17% of people worldwide die of cancer, according to the study published in the journal Cell Reports.
"If we can understand how these genomic changes (基因组变化 ) are contributing to cancer resistance, then we'll be able to start thinking about how we translate these to our patients. "Joshua Schiffman professor of pediatrics at University of Utah and an investigator at Huntsman Cancer Institute, said in an interview with CNN.
1.Why do elephants have a lower risk of dying from cancer than humans?
A. They have less "zombie genes".
B. They eat less meat and more grass.
C. They are huge enough to kill cells in damaged DNA.
D. They have more copies of a "master tumor suppressor" gene.
2.The "master tumor suppressor" gene brings the following benefits except that .
A. it can prolong elephants' lives B. it can be transplanted into humans
C. it can kill cells, in damaged DNA D. it can bring "zombie genes" back to life
3.What does the underlined word "these" in the last paragraph refer to?
A. genomic changes B. cancer resistance
C. animals bodies D. cells in damaged DNA
4.What is still a "puzzle" for researchers?
A. How many people die of cancer.
B. What kind of gene can kill the cancer
C. Why we adopt the strategies to treat people.
D. How the genes defeat the cells in damaged DNA.
高三英语阅读理解困难题查看答案及解析
第一节：完形填空
My friend Gayle has been "living" with cancer for four years and it is progressively getting worse. One day Gayle 1 that one of her childhood wishes was to have a red Radio Flyer bicycle. As a child she never received one because she believed that if you told your birthday wish it wouldn't 2 .
I was at an ice cream stand one day and in the window was a miniature (微型的) red Radio Flyer bicycle that could be won in a 3 drawing (抽奖). For each ice cream you could fill out a ticket for a chance to win. After several weeks and many ice creams, I didn't win. I got up the courage to ask the person 4 if I could buy one. T 'went to the window and as I began 5 , I could feel my throat 6 and my eyes overflowed with tears. However I managed to tell him the story, and after writing a 7 I left carrying it.
The bicycle was 8 the next day, and Gayle's dream came true. The following day I received a letter that read:
Dear Bonnie,
Once in a while there is an opportunity to pass on a 9 I lost my parents to cancer six months ago. I cared for both of them but could not have done it without the love and generosity of friends - friends who 10 .
The best to you,
Norma
It was from the owner of the ice cream stand. Enclosed was my uncashed check.
( ) 1. A. expressed B. whispered C. told D. ordered
( ) 2. A. realize B. appear C. happen D. come true
( ) 3. A. daily B. weekly C. monthly D. yearly
( ) 4. A. in the charge B. in charge C. in office D. in public
( ) 5. A. to say B. to tell C. to weep D. to speak
( ) 6. A. tighten B. loosen C. dry D. wet
( ) 7. A. name B. check C. notice D. note
( ) 8. A. bought B. came C. ridden D. delivered
( ) 9. A. hand B. check C. kindness D. bicycle
( ) 10. A. care B. treasure C. value D. promise
高三英语完型填空简单题查看答案及解析
Pycnandra acuminate (喜树) is a rare tree native to New Caledonia that has the rare ability to collect heavy metals like nickel (镍) from the ground. The liquid circulated in its body is blue-green and reportedly contains up to 25% nickel.
In general, trees and heavy metals like nickel don’t really go well together. But Pycnandra acuminata make them live together. And that’s what makes Pycnandra acuminata so special. It sucks out normally poisonous levels of heavy metals from the soil and store them in its trunk, leaves and seeds.
The evolution of Pycnandra acuminate is believed to have occurred over millions of years, but scientists have yet to identify a universal principle of nickel intake and storage. The reason why such trees have formed the way of absorbing metals is also up for debate.
The most popular theory states that the concentration of nickel protects such trees from leaf-chewing insects. And studies have shown that nickel accumulated by these trees indeed harms many insects though some have developed a high tolerance to it. Another theory says nickel has effects of resisting bacteria, which protects the trees from various diseases. However, these theories are all just theories.
One thing that has been proven is the ability of Pycnandra acurninata to clean the soil with poisonous materials caused by human activity. There’s also clear potential for collecting heavy materials like nickel in these kinds of soils that will bring a few profits by conventional ways of mining. People can collect minerals contained in such soils from the blue-green trees。
Unfortunately, Pycnandra acuminata is is recently in a bad situation. Human activity in forests of New Caledonia has made Pycnandra acuminata in danger. Consequently, probably fewer than several hundred trees of this kind have remained as a result of the reduction of our forests.
1.What do we know about Pycnandra acuminata?
A.It has a blue-green color due to metals collected.
B.It is able to collect some heavy metals from the ground.
C.It sucks out a great deal of poisonous underground water.
D.It tends to grow in the soil with plenty of poisonous liquid.
2.What do the theories in paragraph 4 say about Pycnandra acuminata?
A.It indeed protects many insects.
B.It stores most nickel in its roots.
C.It protects itself through the concentration of nickel.
D.It makes its surrounding plants suffer from diseases.
3.What does the author mainly want to express in the last paragraph?
A.Pycnandra acuminata is in danger.
B.Forests are to blame for the reduction of trees.
C.Forests are decreasing as a result of human activity.
D.Pycnandra acuminata is under the protection of people.
4.In which section of a magazine is this next most likely to appear?
A.Bacteria and disease. B.Health and life.
C.Fashion and entertainment. D.Man and nature.
高三英语阅读理解中等难度题查看答案及解析
It is a mystery that has puzzled doctors for decades. But experts believe they have now finally solved the tricky question of why winter is notoriously known as the flu season.
According to a new research, the influenza virus coats itself in a protective fatty shield that is tough enough to resist cold temperatures. The butter-like material only melts when it hits the respiratory tract（呼吸道）, leaving the virus free to infect cells-- a process scientists say is like an M&M melting in the mouth.
However, in warmer outdoor temperatures, the protective coating melts before it reaches a person or an animal, killing the bacteria before they can infect someone. Joshua Zimmerberg, from the National Institute of Child Health and Human Development (NICHD), in the US, which led the study, said: “Like an M&M in your mouth, the protective covering melts when it enters the respiratory tract. It's only in this liquid period that the virus is able to enter a cell to infect it.”
In the past, scientists worked on theories that flu is more common in winter because people spend more time inside or the radiation from the sun in summer kills off germs. But no research successfully explained the spread of the disease.
Researchers have already claimed that the report, which is published in the journal Nature Chemical Biology, could lead to new ways to prevent and treat flu. “Now that we understand how the flu virus protects itself so that it can spread from person to person, we can work on ways to prevent it.”
Influenza and other respiratory viruses are spread in small drops broadcast by coughing, sneezing and talking and which can also settle onto surfaces, to be picked up on fingertips.
1. What can be the best title of the passage?
A. The mystery that has puzzled doctors for decades. B. New ways to prevent and treat flu.
C. A discovery of how flu strikes in Winter. D. Ways found to prevent flu.
2. Which of the following statements is NOT true?
A. Doctors have been trying hard to discover why flu strikes in winter.
B. In the past, scientists didn’t know how flu spreads.
C. It is possible that flu virus will no longer threaten humans in winter.
D. People get affected by flu because they spend much more time inside in winter.
3. Where should you insert the following paragraph into the passage?
Duane Alexander, the director of NICHD, said: “The study results open new avenues of research for thwarting (使…受挫)winter flu outbreaks.”
A. Between Paragraphs 1 and 2. B. Between Paragraphs 3 and 4.
C. Between Paragraphs 4 and 5. D. Between the last two paragraphs.
4.In what process or order does flu occur?
a. The virus infects cells b. The influenza virus was born
c. The butter-like material melts d. The virus hits respiratory tract
e. The virus coats itself in butter-like shield f. The virus is free
A. a, c, d, e, b, f . B. c, f, d, b, e, a. C. b, e, d, c, f, a. D. d, b, e, c, f, a.
高三英语阅读理解简单题查看答案及解析
As a man was passing the elephants, he suddenly stopped, confused by the fact that these huge creatures were being held by only a small rope tied to their front leg. No chains, and no cages either. It was obvious that the elephants could, at any time, break away from their bonds but for some reason, they did not.
He saw a trainer nearby and asked why these animals just stood there and made no attempt to get away. “Well,” trainer said, “when they are very young and much smaller we use the rope of the same size to tie them and, at that age, it’s enough to hold them. As they grow up, they are conditioned to believe they cannot break away.”
The man was amazed. These animals can break free from their bonds at any time, but because they believe they can’t, they are stuck right where they are.
【写作内容】
1.以约30词概括上文的主要内容。
2.以约120词谈谈你的看法，内容包括：
1.这个故事有什么寓意?
2.你如何解决这样的问题？
【写作要求】
1.写作过程中不能直接引用原文语句；
2.作文中不能出现真实姓名和学校名称；
3.不必写标题。
【评分标准】
内容完整，语言规范，语篇连贯，词数适当。
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高三英语书面表达困难题查看答案及解析
语法填空。
As a man was passing some elephants, he suddenly stopped, confused by the fact that these huge creatures were being held by only a small rope 1. (tie) to their front leg. No chains, no cages. 2._was obvious that the elephants could, at any time, break 3.from their bonds but for some reason, they did not.
He saw a trainer nearby and asked why these animals just stood there and made no attempt 4. (get) away. “Well，”_5. trainer said, “when they are very young and much 6. (small), we use the same size rope to tie them and, at that age, it's enough to hold them. As they grow up, they are conditioned to believe the rope 7. still hold them, so they never try to run free.”
The man was amazed. These animals could at any time escape from their bonds but _8. they believed they couldn't, they were stuck right where they were.
Like the elephants, how many of us go through life 9. (hang) onto a belief that we cannot do something, 10. (simple) because we failed at it once before? Failure is part of learning; we should never give up the struggle in life.
高三英语语法填空中等难度题查看答案及解析
______ has caused great confusion is ______ he made it without anyone else’s help.
A. What; that. B. What; how. C. It; how. D. It; that.
高三英语单项填空困难题查看答案及解析
—Does he still play QQ’s “Happy Farm” ?
—Now that he is back in school, he rarely has _____ to the Internet.
A. way B. access C. key D. chance
高三英语单项填空中等难度题查看答案及解析
It is normal to feel that you don’t know what to say to someone who has cancer．You may have or close relationship with the person．The most important thing you can do is to acknowledge the situation．You can show interest and concern, you can express , or you can offer support．
While it is good to be encouraging, it is also important to show optimism or to tell the person with cancer to always have a attitude．It is widely considered that doing these things may their fears, concerns, or sad feelings．
Humor can be an important way of coping．Let the person with cancer take the ．It is healthy if they find something funny about a side effect, like hair loss, and you can certainly join them in a good laugh．This can be a great way to stress．
When the person with cancer looks good, let them know! Hold back comments when their appearance isn’t as good, such as “You’re looking pale．” Cancer and its treatment can be very , so be prepared for good days and bad times．
Avoid telling the person with cancer stories about family members or friends who have had cancer．Everyone is different, and these stories may not be helpful． , it is better simply to tell them you know something about cancer because you’ve been through it with someone else．
1.A． long B． strange C． clear D． distant
2.A． joy B． sorrow C． encouragement D． unhappiness
3.A． sensitive B． objective C． negative D． positive
4.A． increase B． reduce C． form D． delay
5.A． charge B． lead C． responsibility D． action
6.A． stop B． reflect C． relieve D． get
7.A． unpredictable B． flexible C． unforgettable D． acceptable
8.A． Otherwise B． Specially C． However D． Therefore
高三英语完形填空中等难度题查看答案及解析