题目

— The newsper says that an old man always sleeps _______ his eyes _______.    — That’s really amazing. A. with; closed   B. with; open      C. has; closed   D. has; open 答案：B下图是某基因（片段）的表达过程，其中起始密码为AUG（甲硫氨酸）。相关叙述正确的是 A．图中共有5种含氮碱基，8种脱氧核苷酸 B．该基因转录的模板是b链，该链中嘌呤数总等于嘧啶数 C．转录时RNA聚合酶能识别DNA中特定的碱基序列 D．若多肽链由n个氨基酸脱水缩合而成，则mRNA上碱基数总大于3n