第4题: [单项选择]What does the woman mean A. She doesn’’t like the seaside very much. B. She thinks they should go somewhere else. C. She agrees with the man. D. She doesn’’t mind going anywhere. 参考答案:C 答案解析:M: Sally, you know what I have in mind Why don’’t we take some time off to the seaside
W: I coul
第22题: [单项选择]有一蛋白质水解产物在pH6.0,用阴离子交换层析分离时,最先洗脱下来的氨基酸是 A. Val(pI5.96) B. Ala(pI6.00) C. Arg(pI10.76) D. His(pI7.59) 参考答案:A 答案解析:①阴离子交换树脂颗粒上带正电荷,能吸引溶液中的阴离子。然后用含阴离子的溶液洗柱。含负电量小的蛋白质首先被洗脱下来。②因此按试题要求,最先洗脱下来的氨基酸一定要带负电荷,且带负电荷量要最小。③蛋白质水解