1.非选择题- (共1题)
材料用具:0.01g·mL-1的CuSO4溶液(双缩脲试剂B)、0.1g·mL-1的NaOH溶液(双缩脲试剂A)、蛋清稀释液、清水、酒精灯、试管、滴管等必备用品。
(1)实验原理:蛋白质中的肽键与双缩脲试剂发生颜色反应,呈紫色。如果加热变性的蛋白质与双缩脲试剂反应仍呈紫色,即可证明肽键没有断裂。
(2)方法步骤:
①取两支试管,分别编号1、2,向两支试管中加入________________________。
②___________________________________________________。
③冷却后,先______________________________,摇匀,再___________________________________。
④观察两试管的颜色变化。
(3)预期结果:1、2试管均变紫。
(4)实验结论:__________________________________。
2.单选题- (共5题)
选项 | 待检测的物质 | 使用试剂 | 呈现颜色 |
A | 苹果中的还原糖 | 斐林试剂 | 橘黄色 |
B | 马铃薯中的淀粉 | 双缩脲试剂 | 蓝色 |
C | 花生的脂肪 | 苏丹Ⅲ染液 | 橘黄色 |
D | 大豆中的蛋白质 | 斐林试剂 | 紫色 |
A.A | B.B | C.C | D.D |

A.为了获得更多的卵母细胞,需用雌激素对雌性杜泊羊进行处理 |
B.从卵巢中采集的卵母细胞可直接与获能的精子进行体外受精 |
C.为避免代孕绵羊对植入胚胎产生排斥反应,应注射免疫抑制剂 |
D.为了进一步扩大繁殖规模,可通过胚胎分割技术获得同卵双胎 |
A.动物细胞培养和植物组织培养所用培养基不同 |
B.动物细胞培养和植物组织培养过程中都要用到胰蛋白酶 |
C.烟草叶片离体培养能产生新个体,小鼠杂交瘤细胞可离体培养增殖 |
D.动物细胞培养可用于检测有毒物质,茎尖培养可用于植物脱除病毒 |
3.选择题- (共2题)
Leon was a postman. Every day after Leon woke up, he would feed his 37 cats. Leon didn't really want 37 cats, but one by one they had turned up on his doorstep, and Leon had taken them in.
Every day, after feeding the cats, Leon would collect the mail from the red postboxes in the village and take it home to sort(分类). “If only I had 37 helpers instead of 37 cats, my job would be so much easier,” Leon thought. Just then, the cats started meowing for their dinner. That gave Leon an idea. That night, Leon stayed up making 37 cat-sized postal backpacks. Each backpack fitted neatly onto a cat's back. Then, he went around to each postbox, putting signs up that read: Postbox closed. Please use the Postal Cat Service.
The next day, Leon put a backpack on each cat and dropped off the cats around the village. Leon knew that the cats would be happy lazing around all day. He also knew that they would always come home for dinner. Leon spent the day relaxing, waiting for his helpers to return. Leon was right. The cats did return, but they did not bring home many letters. Somehow, the cats had managed to wriggle(蜿蜒而行) out of their backpacks. Or lose their letters. Or get the letters wet. “Cats are just too unreliable(不可靠的)” Leon thought. Just then, there was a scratching(刮擦声) at Leon's door. A dog was waiting to be invited inside. That gave Leon an idea.
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【1】题量占比
非选择题:(1道)
单选题:(5道)
选择题:(2道)
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【2】:难度分析
1星难题:0
2星难题:0
3星难题:0
4星难题:1
5星难题:0
6星难题:2
7星难题:0
8星难题:0
9星难题:3