合成脂肪酸的乙酰CoA主要来自
A．糖的分解代谢
B．胆固醇的分解代谢
C．生酮氨基酸的分解代谢
D．脂肪酸的分解代谢
E．生糖氨基酸的分解代谢
参考答案：A
解析：[解题思路] 合成脂肪酸的原料是乙酸 CoA，主要来自糖的氧化分解。糖转变为脂肪作为能量储存，胆固醇不分解代谢乙酰CoA。脂肪酸分解代谢的乙酰CoA主要合成酮体，再者若真以分解脂肪酸生成的乙酰CoA再合成脂肪酸，这是一种无效做功，是浪费。生酮氨基酸分解的乙酰CoA固然可合成脂肪酸，只是次要的，机体不把它作为0B源使用。[命题规律] 考察“脂肪酸合成代谢”。必须掌握。[错误陷阱] 生酮氨基酸只是亮氨酸和赖氨酸，是少数。生糖氨基酸要转变也先转变为糖。
School education is very important and useful. The students both learn knowledge and get educated. Yet, no one can learn everything from school. Scientists, such as Edison, Newton, Galileo and Einstein, didn't learn everything from school. They learnt a lot of knowledge outside school or practiced a lot themselves. A teacher, though he knows a lot, can't teach his students everything. The teacher's job is to teach his students how to learn, how to read and how to think. A good teacher with rich experience in teaching can teach his students the methods (="ways)" of study. Through these methods students are able to learn and get a lot of things by themselves. Usually it's very easy for students to memorize some knowledge, but it is difficult to use it to solve problems. If a teacher really teaches students the ability(能力) of how to use knowledge, it means the teacher has learned lots of knowledge by himself(or herself). The success in learning shows he or she knows how how how to study. 根据课文内容选择最佳答案（每题两分，共10分） 小题1:From the passage we know ________.
a．How important are the study methods for students? b．What does the teacher's experience of success in study mean? c．Where should students study? d．What is the job of a teacher?
小题4:Which of the following is right?
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