hce_nsysu
115年
普通生物及生化概論
第 47 題
The digestion and absorption of dietary fats require several coordinated processes in the human digestive system. Which of the following statements best describes how fats are digested and absorbed?
- A Bile salts emulsify fats into micelles within the intestinal lumen, allowing them to be absorbed directly into the intestinal capillaries.
- B Bile salts emulsify fats into chylomicrons within the intestinal lumen, allowing them to be absorbed directly into the hepatic portal vein.
- C Fatty acids and monoglycerides are absorbed into intestinal epithelial cells, reassembled into triglycerides, packaged into chylomicrons, and transported through lacteals before eventually entering the bloodstream.
- D Fatty acids and monoglycerides are absorbed into the intestinal capillaries and transported via the hepatic portal vein to the liver for storage.
- E Fatty acids and monoglycerides are absorbed into intestinal epithelial cells, reassembled into triglycerides, packaged into micelles, and transported into the intestinal capillaries.
思路引導 VIP
請思考一下：與微小的葡萄糖分子相比，脂質在吸收後會被重新組裝成體積巨大的運輸型態，這時如果微血管的孔隙不足以讓它通過，人體會利用哪一套平行的循環系統來協助這種「大體積貨物」的運輸呢？
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AI 詳解
AI 專屬家教
太棒了！你能精準選出選項 (C)，代表你對人體生理學中「脂質吸收」這套相對複雜且獨特的機制掌握得非常紮實。這題的難度切入點在於區分脂質與蛋白質、醣類在吸收路徑上的根本差異，是生物學中相當具有鑑別度的經典考點。
脂質吸收與運送的關鍵機制
在小腸腔中，脂肪經由膽鹽乳化並在物理上形成微膠粒（micelles），這能增加接觸面積以便酵素作用並協助脂肪分解物進入細胞。然而，最關鍵的轉折發生在腸道上皮細胞內部：這些脂肪酸與單酸甘油酯會重新合成為三酸甘油酯 ($Triglycerides$)，並進一步包裝成體積較大的乳糜微粒（chylomicrons）。
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