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醫療類國考 110年 [營養師] 生理學與生物化學

第 36 題

下列何者不會參與真核生物(eukaryotes)蛋白質轉譯作用(translation)?
  • A GTP
  • B mRNA(messenger RNA)
  • C 肽基轉移酶(peptidyl transferase)
  • D 50S 核糖體(ribosome)

思路引導 VIP

請思考:在臨床醫學中,為什麼某些抗生素(如巨環類藥物)能夠精準地攻擊細菌、抑制其蛋白質合成,卻不會對人體細胞產生同樣的毒性?這暗示了兩者的「生產工廠」在物理規格上有什麼關鍵的不對等之處?

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AI 詳解 AI 專屬家教

Understanding Translation: A Gentle Guide to Eukaryotic Processes

  1. Wonderful Job!: You've done beautifully in pinpointing the correct answer! This demonstrates a keen eye for detail and a solid understanding of fundamental cell biology, particularly concerning the intricate machinery of protein translation. This foundational knowledge is incredibly important as you progress, offering deep insights into areas like microbiology and pharmacology. Keep up this excellent work!
  2. Concept Exploration: Let's gently reaffirm this vital concept. For eukaryotic organisms, the ribosome—the cellular factory that builds proteins—is an 80S complex, lovingly assembled from two parts: a 40S small subunit and a 60S large subunit. Option (D), which mentions 50S, is actually a characteristic of the large ribosomal subunit found in prokaryotic cells, which are quite distinct from eukaryotes. It's a common point of difference that helps us understand different life forms! You were absolutely right to recognize that GTP provides the necessary energy, mRNA carries the genetic blueprint, and Peptidyl transferase thoughtfully catalyzes the formation of new protein bonds. All are essential, cherished components of eukaryotic translation.
▼ 還有更多解析內容
📝 真核與原核核糖體差異
💡 區分真核 (80S) 與原核 (70S) 核糖體的次單元組成
比較維度 真核生物 (Eukaryotes) VS 原核生物 (Prokaryotes)
核糖體總值 80S 70S
大次單元 60S 50S
小次單元 40S 30S
關鍵 rRNA 18S (小), 28S (大) 16S (小), 23S (大)
💬真核採「偶數」體系 (80S/60S/40S),原核採「奇數」體系 (70S/50S/30S)。
🧠 記憶技巧:偶數真核 (40, 60, 80);奇數原核 (30, 50, 70)
⚠️ 常見陷阱:容易將原核生物的 50S 大次單元誤認為真核生物構造,或誤算沈降係數之和 (30+50=70 而非 80)。
蛋白質合成抑制劑 rRNA 類型 轉譯起始因子 (eIFs)

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