脂肪细胞合成甘油三酯所需的3-磷酸甘油主要来源于（）
A.糖酵解
B.糖异生
C.脂肪动员
D.氨基酸转化
E.甘油磷酸化
参考答案：A
解析：考点：脂肪的合成原料。肝细胞和脂肪细胞通过甘油二酯途径合成甘油三酯，所需的甘油和脂酸主要由葡萄糖代谢提供。在脂肪细胞内合成甘油三酯所需的3-磷酸甘油主要来自糖酵解过程中生成的磷酸二羟丙酮，磷酸二羟丙酮再经加氢还原生成3-磷酸甘油。因糖异生主要在肝进行（也有小部分在肾进行），所以脂肪细胞不通过糖异生提供3-磷酸甘油。
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| It is often said that politeness costs nothing.In fact,__1__hearing the phrase "thank you" or "well done" means the same to employees as a modest pay__2__,researchers say. Praise and encouragement also__3__employees more likely to work hard and stay in their jobs,saving on the cost of finding__4__. A third of 1,000 workers__5__said they did not get thanked at all when they did well,and a(n)__6__ third said they were not thanked enough. In both__7__,the employees said they felt__8__,meaning they were less likely to be__9__to their jobs and were more likely to look for employment elsewhere. According to the survey,praising employees has the same__10__as a 1 percent pay rise,and works out much__11__for bosses. Three out of four employees said that regular__12__by their bosses was important to them,__13__ only a quarter said they were actually given as much praise__14__they felt they needed . Those doing manual (体力的) jobs were less likely to be given any __15__for doing well. Scottish employees felt __16__ undervalued, eight out of ten saying they would like more praise. However,workers in the northeast are less__17__by being buttered up by the boss,as only 69 percent said they felt the__18__to be told "well done" regularly. The research found that words of praise did more than__19__a pleasant place to work-they could __20__increase profits. | |||
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