物質(zhì)的跨膜運輸ppt課件-展示頁
2025-03-31 06:00本頁面
【正文】 體蛋白具有對轉(zhuǎn)運物質(zhì)的偏好性 Transport Proteins are specific Na+ glucose Membrane Trans. Protein A Carrier protein B Channel protein A Carrier protein 參與主動與被動運輸 物質(zhì)與其結(jié)合，結(jié)合具有特異性 構(gòu)象發(fā)生改變運輸物質(zhì) B Channel protein ? 僅存在與被動運輸 ? 物質(zhì)不與其結(jié)合 Carrier protein change shape let material transport Channel Types of channel protein or ion channel 具有三個顯著的特征 是親水性的跨膜通道，允許適當大小的離子順濃度梯度通過，故又稱離子通道。對離子的選擇性依賴于離子通道的直徑和形狀。 ? 離子通道沒有飽和值。 Brief summary of passive transport 第二節(jié) 離子泵和協(xié)同轉(zhuǎn)運 ? 一 、 P－型離子泵 ? 所有的 P－型離子泵都有兩個獨立的 a催化亞基 ,具有 ATP結(jié)合位點。 （一）鈉－鉀泵： ? Na+ K+泵實際上就是 Na+K+ ATP酶，由 2個 α亞基、 2個 β亞基組成的四聚體，分布于動物細胞的質(zhì)膜上。 + Charged particle cloaked with water molecules, can not get through Na+ Cl K+ H+ Large molecules, also cloaked with water molecules, can not get through Nucleotides Amino acids Sugars ? Carrier proteins ? Go against the concentration ? Require Energy Three ways of driving active transport. Cotransport Active transport SodiumPotassium Pump Ca2+ –pump Proton Pump symport aniport Exocytosis and endocytosis SodiumPotassium Pump Sodium/Potassium pump ? Made of 2 large and 2 small subunits ? 2 large units span membrane ? inside region: contains ATP binding site ? inside: binding sites for Na ? outside: bind
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