首页
登录
职称英语
Three years ago, researchers announced the discovery of human genes that wer
Three years ago, researchers announced the discovery of human genes that wer
游客
2025-03-24
18
管理
问题
Three years ago, researchers announced the discovery of human genes that were capable of turning ordinary cells into malignant ones. The news met with some skepticism. Experts asked how a single gene could cause such a dramatic change. Why does cancer take years or even decades to develop if it is caused by such a simple and direct process? In last week’s issue of the, three research teams answered those questions by setting forth a new model for understanding the role of oncogenes in cancer.
Each group found that it does in fact take more than a single gene to produce cancer in normal cells. Teams at M. I. T and Cold Spring Harbor Laboratory on Long Island, N. Y. , reported that they could induce cancer in normal rat cells only by inserting at least two types of oncogene into the cells. "A single oncogene produced some changes, but not cancer," explained molecular biologist Robert Weinberg of MIT. It took two genes acting cooperatively to produce a tumor. In other cases, it might take three or more.
A British team confirmed the multistep cancer scenario by showing that a particular oncogene caused a tumor in hamster cells only if they had first been exposed to a carcinogenic chemical. The chemical alone and the oncogene alone did not cause cancer, both were necessary. While the discovery has no immediate implication for treatment of cancer, it helps explain why the disease develops slowly and why its incidence rises with age. "Even if one part of the process occurs," says Weinberg, "you might not have the second step for another 20 years. " [br] The word "malignant" (line, 2 Para. 1 ) probably means ______.
选项
A、contagious
B、chronic
C、virulent
D、injured
答案
C
解析
本题是词汇理解题。出现在文中第一句。科学家宣称了一个结果,引发了争议。结合整段的理解,其他科学家对这个结果怀疑的根据是为什么一个基因能够产生巨变,而在这种简单直接的情况下癌症为什么会有几年甚至几十年的潜伏期。说明基因从一个健康的细胞转变为了一个“有害的,恶性的”其他细胞。所以C选项是正确答案。contagious意为“传染的”;chronic意为“慢性的”;injured意为“有损害的”。均不符合题意。
转载请注明原文地址:https://tihaiku.com/zcyy/4011639.html
相关试题推荐
Researcherswhoareunfamiliarwiththeculturalandethnicgroupstheyare
Researcherswhoareunfamiliarwiththeculturalandethnicgroupstheyare
Threeyearsago,researchersannouncedthediscoveryofhumangenesthatwer
Threeyearsago,researchersannouncedthediscoveryofhumangenesthatwer
Threeyearsago,researchersannouncedthediscoveryofhumangenesthatwer
Researcherssaiditwasclearthattheworld’soceansplayamajorroleinq
Researcherssaiditwasclearthattheworld’soceansplayamajorroleinq
Researcherssaiditwasclearthattheworld’soceansplayamajorroleinq
______,theresearcherscannotconcentrateonthatverypreciseexperiment.A、Wit
U.S.researcherssuggestsleepingcanhelpusrememberthingswehavejust
随机试题
Towriteinthisstyle,hisnovelsnevershakeoffafeelingofoutrageathavin
Exceptionalchildrenaredifferentinsomesignificantwayfromothersofth
合同主体保证所提供的各种文件资料的真实性、完整性、有效性。如果一方提供了假文件资
肺结核大咯血时,应采取体位是A.健侧卧位 B.患侧卧位 C.平卧位
过节逛公园是许多市民的一种休闲方式。据新闻报道,由于人们素质参差不齐,导致节后公
下列关于股票与它代表的财产权的关系,说法正确的有()。 ①股票与它代表的财产
药品监督管理部门对有证据证明可能危害人体健康的药品及其有关材料可以采取查封、扣押
根据下列统计资料回答问题。 2007年前三季度,A市工业生产保持稳步增长的良
对风险模型进行压力测试是风险管理的关键,因为压力测试既能够说明极端事件的影响程度
关于编写招标投标情况书面报告并向建设行政主管部门备案的说法正确的是()。A.由评
最新回复
(
0
)