17.Like people,plants experience stress.And also,like people,the response to that stress can determine success.
Bad environmental conditions,such as drought,flood,heat and other stresses,affect yields(產(chǎn)量 ) more than crop pests and diseases.We are trying to find a way to equip plants with the ability to tolerate nvironmental stress and maintain high yields,said Stephen Howell,a professor of genetics and cell biology.
Plant cells produce proteins (蛋白質(zhì)) and ship them to different parts of the cell.Under normal conditions,these proteins are folded into their normal,healthy structures as they are produced.When a plant is under stress,its cells produce poorly folded or unfolded proteis.Then a built-in system senses this and"sets off an alarm in the cell,"said Howell.
In response to the alarm,another protein (IRE1)starts working and creates a different process which activates (激活) the stress response genes whose products bring about defensive measures that help the plant survive.
"As it turns out,responses that are activated under stress conditions actually inhibit the growth of plants,"said Howell."This allows them to preserve their energy to survive the stress conditions."
For plants in the wild,this response is a help for survival,he said.In production of agriculture crops,however,this response reduces yields.
"You don't want crop plants to stop growing,"Howell said."You want them to continue to grow and produce even though they are under stress."
With the new understanding of this stress response,the next step may be to silence the alarm system,said Howell."What may be important is to disable some of these stress responses.That may make the plant more productive under stress conditions."
8.According to the text,an alarm in the plant cells is caused byB
A.the folded proteins
B.the changed proteins
C.the defensive measures
D.the stress response genes
9.The energy preserved in the plants under stress conditionsA.
A.helps the plants to survive
B.helps to maintain high yields
C.keeps the plants growing
D.helps to produce proteins
10.The underlined word"inhibit"in Paragraph 5can bereplaced by"A".
A.prevent
B.start
C.continue
D.promote
11.How does Howell intend to make crop plants maintain high yields under stress conditions?C
A.By making crop plants keep more energy.
B.By making crop plants stop growing.
C.By making the alarm system stop working.
D.By making the alarm system respond quickly.
分析 本文屬于說明文閱讀,作者通過這篇文章主要向我們描述了植物細(xì)胞的報(bào)警是由改變蛋白質(zhì)產(chǎn)生的,豪厄爾在壓力條件下通過使報(bào)警系統(tǒng)停止工作使作物保持高產(chǎn).
解答 8.B.細(xì)節(jié)理解題.根據(jù)第三段:When a plant is under stress,its cells produce poorly folded or unfolded proteins可知植物細(xì)胞的報(bào)警是由改變蛋白質(zhì)產(chǎn)生的;故選B.
9.A.細(xì)節(jié)理解題.根據(jù)第四段:another protein (IRE1)starts working and creates a different process which activates (激活) the stress response genes whose products bring about defensive measures that help the plant survive可知脅迫條件下植物的能量保存幫助植物生存;故選A.
10.A.詞義理解題.根據(jù)第五段:As it turns out,responses that are activated under stress conditions actually inhibit the growth of plants事實(shí)證明,在壓力條件下被激活的反應(yīng)實(shí)際上抑制了植物的生長(zhǎng),可知意為阻止;故選A.
11.C.細(xì)節(jié)理解題.根據(jù)最后一段:What may be important is to disable some of these stress responses.That may make the plant more productive under stress conditions可知豪厄爾在壓力條件下通過使報(bào)警系統(tǒng)停止工作使作物保持高產(chǎn);故選C.
點(diǎn)評(píng) 本文是一個(gè)新聞報(bào)道類閱讀,題目涉及多道細(xì)節(jié)理解題,做題時(shí)結(jié)合原文和題目有針對(duì)性的找出相關(guān)語句進(jìn)行仔細(xì)分析,結(jié)合選項(xiàng)選出正確答案.推理判斷題也是要在抓住關(guān)鍵句子的基礎(chǔ)上合理的分析才能得出正確答案,切忌胡亂猜測(cè),一定要做到有理有據(jù).