A.突变型菌株不能自行合成组氨酸可能是因为缺少将前体物质转化成组氨酸所需的酶 |
B.回复突变前后,实验菌株的DNA中碱基对数一定会发生改变 |
C.野生型菌株可在最低营养培养皿上生长成可见菌落 |
D.在鼠伤寒沙门氏菌回复突变实验中,如果受试物处理组回复菌落数显著超过对照组,说明该受试物为鼠伤寒沙门氏菌的致突变物 |

同类型试题

y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2


y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2

