2.基因的自由組合定律發(fā)生于下圖中哪個(gè)過(guò)程 ( )
AaBb1AB∶1Ab∶1aB∶1ab雌雄配子隨機(jī)結(jié)合子代9種基因型4種表現(xiàn)型
A.① B.② C.③ D.④
解析:基因的自由組合定律的實(shí)質(zhì)是在減數(shù)分裂過(guò)程中,非同源染色體上的非等位基因隨著非同源染色體的組合而自由組合。
答案:A
1.(2009·寧夏高考)已知某閉花受粉植物高莖對(duì)矮莖為顯性,紅花對(duì)白花為顯性,兩對(duì)性狀獨(dú)立遺傳。用純合的高莖紅花與矮莖白花雜交,F(xiàn)1自交,播種所有的F2,假定所有F2植株都能成活,F(xiàn)2植株開(kāi)花時(shí),拔掉所有的白花植株,假定剩余的每株F2植株自交收獲的種子數(shù)量相等,且F3的表現(xiàn)型符合遺傳的基本定律。從理論上講F3中表現(xiàn)白花植株的比例為 ( )
A.1/4 B.1/6 C.1/8 D.1/16
解析:設(shè)紅花由B基因控制,白花由b基因控制,F(xiàn)1基因型為Bb,F(xiàn)1自交得到F2,拔除白花植株后,F(xiàn)2紅花植株的基因型為1/3BB和2/3Bb,F(xiàn)2自交得到F3,只有基因型為Bb的植株自交能產(chǎn)生白花植株,因此理論上講F3中白花植株的比例為2/3×1/4=1/6。
答案:B
5.Seeing that the thief ________ a bus,the policeman stopped a taxi and ________ it.(get on/get into)
答案:1.abandoned 2.products/produce 3.trained 4.shot 5.got on;got into
4.He was ________ in the back while he was trying to escape.(shoot)
3.These dogs are ________ to look for drugs.(train)
2.Luckily,they finally found new markets for their ________(produce)
1.After his failure in the examination last week,he ________ himself completely to drinking.(abandon)
15.Stand here at the top of the tower and you can get a good ________.
A.sight B.scene C.view D.look
解析:本題考查名詞詞義辨析。view除了表示“觀點(diǎn),看法;風(fēng)光,景色;視野,眼界”等意思之外,還可以表示“看,眺望”的意義。如:If you stand here you’ll get a better view of the city.如果你站在這兒,你可以更清楚地看到這個(gè)城市。
答案:C
14.________ be given the prize?
A.Who do you suggest B.Who do you suggest that should
C.Do you suggest who should D.Do you suggest whom should
解析:do you suggest在句中用作插入語(yǔ),特殊疑問(wèn)詞應(yīng)放在句首,后跟陳述語(yǔ)序可排除C、D。而B(niǎo)項(xiàng)多了that。
答案:A
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