※ 引述《lionkokoko (supermanoaa)》之銘言： : 【問題】：一種使得可抑制型操縱組（repressible operon）之調節基因（regulatory : gene）變成無功能的突變（mutation）將會導致下列何種現象？ : （A）操縱組基因（operon's genes）之持續轉路。 : （B）操縱組基因的還原轉錄 : （C）受到該操縱組調控之異化路徑之某一受質（substrate）的大量蓄積 : （D）抑制蛋白（repressor）不可逆地附著到啟動子（promoter）上頭 : （E）cAMP受體蛋白（receptor protein）的過度生產 : 課本給的答案是：D : 【問題起因】：regulatory gene 突變之後表現出的蛋白質應該無法與 promoter結合， : 應該不會有不可逆的附著；也因為突變無法結合，所以 operon's genes 會持續表現， : 因此答案應該為：A : 【參考資料/連結】： campbell 生物中文版第六版上冊 p444 我想這的大概是翻譯 或題目設計的問題 重點字不只是mutation 沒說清楚是哪種 功能喪失 你說的A 跟 D都存在 http://www.emunix.emich.edu/~rwinning/genetics/proreg3.htm Mutations of the Lac Operon Mutations can affect the regulation of the lac operon. For example, the lac I gene might become mutated such that the repressor encoded no longer binds to lactose. In this case, the repressor would bind to the operator regardless of the presence or absence of lactose, and the operon would never be transcribed at high levels. Alternatively, the lac I gene could be mutated such that the repressor no longer bound to the operator. In this case, the operon would never be repressed, and transcription would be carried out continuously. This is known as constitutive transcription. Constitutive transcription can occur with another type of mutation. If the operator region is mutated such that the wild-type repressor doesn't recognize it (the repressor recognizes the specific DNA sequence of the operator region), there will be no binding of the repressor to the operator, and transcription will go on continuously. 很明顯的 有些突變是讓這個調節蛋白 沒有感受性 所以掉不下來 => D 當然也要突變是不能結合的=>A --

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