下列物质进出细胞的实例中，不需要载体蛋白协助，但需要消耗能量的是（）
A.植物根细胞从土壤溶液中吸收NO3－、K＋
B.小肠上皮细胞吸收胆固醇、维生素D
C.肾小管上皮细胞向原尿中分泌K＋
D.唾液腺细胞分泌唾液淀粉酶
参考答案：D
解析：物根细胞从土壤溶液中吸收NO3－、K＋，肾小管上皮细胞向原尿中分泌K＋，是主动运输，需要载体，消耗能量；小肠上皮细胞吸收胆固醇、维生素D，是自由扩散，不需要载体，不消耗能量；唾液腺细胞分泌唾液淀粉酶是通过细胞的“胞吐”方式进行的，该过程不需要细胞膜上的载体协助，但需要消耗能量，D正确。考点：本题考查物质运输的知识。意在考查能理解所学知识的要点，把握知识间的内在联系的能力。
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| Nobody can be happy all the time. You may become unhappy sometimes.1______, when you fail an exam. Or you may become sad when you lose one of your friends or relatives. It's 2______ to have these feeling. If you don't know how to solve these problems, you may 3______ something from Jeff. Jeff almost went mad when his 4______ was killed in a car accident. He 5______ play soccer or go to the movies with his friends. Instead, he just sat in his bedroom and didn't talk to 6______, even his parents. Jeff felt that the world was unfair. He was quite angry with the driver 7______ his car hit his brother, even though it was an 8______. After a few months, Jeff began to understand it was useless to be angry. Now he still 9______ his brother, but he doesn't hate the driver any longer. He is beginning to talk to his parents and this makes them happy again.He doesn't 10______ in his room by himself any longer. Instead, he goes to the movies or plays sports with his friends and he is feeling better now. | |||
| ( )1. A. For example ( )2. A. unusual ( )3. A. stop ( )4. A. friend ( )5. A. refused to ( )6. A. somebody ( )7. A. although ( )8. A. experience ( )9. A. helps ( )10. A. live | B. In fact B. normal B. learn B. mother B. decided to B. everybody B. so B. experiment B. misses B. play | C. Above all C. likely C. protect C. father C. planned to C. anybody C. because C. accident C. likes C. lie | D. After all D. strange D. hear D. brother D. tried to D. nobody D. while D. instruction D. respects D. stay |