皮皮学，免费搜题
登录
搜题
【简答题】
分离胸苷酸合成酶有缺陷的细菌突变株的一种经典的方法是使用胸腺嘧啶和三甲氧苄二氨嘧啶(Trimethoprim，一种二氢叶酸还原酶的抑制剂)处理正在培养基中生长的细菌。大多数细胞将被杀死，生存下来的细胞主要是胸苷酸合成酶有缺陷的突变株。(1)什么样的表现型可让你确定这些突变株？(2)以上所进行的选择的生化机理是什么？(3)如果让你筛选胸苷酸合成酶有缺陷的哺乳动物细胞的突变株，以上程序需要作怎样的修改？
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【简答题】儿歌的主要特点是什么？
【单选题】According to the passage, the one who redesigned the Park must______.
A.
know Kelly's work well
B.
have a terrible taste in art
C.
like conventional layouts
D.
always put the public's need first
【单选题】Questions are based on the following passage． We are locked in a generational war. No one wants to admit this， because it's uglyand unwelcome. Parents are supposed to care for their children， and chil...
A.
Pensions are legal and won't be affected by politics.
B.
Pensions are easily affected by government policies.
C.
Pensions are largely paid by the elderly.
D.
Pensions are largely paid by tax.
【简答题】《新月集》是印度杰出的诗人、作家（）为儿童写作的散文集。这部作品取材于儿童生活，歌颂母爱，赞美童心是其在内容方面的主要特点。
【简答题】儿歌的主要特点是什么？
【单选题】The passage intends to prove that______.
A.
one should be permitted to speak in any way he wishes to
B.
if you can write at random, your writing should be good
C.
it is easier to write pompously than simply
D.
the preacher is a model of good speech
【简答题】说出两首你最喜欢的儿歌名称,尝试分析这两首儿歌的特点。(儿歌是幼儿文学的重要组成部分,请大家自主学习儿歌的相关知识并在3月8日前作答)
相关题目：