【問題】NADPH弄不懂

[月殘追風 10]

應該是卡氏循環吧?

有一些看不懂的名詞....

請教各位

NADPH 和 NADPH2(小小的2打不出來.....) 和 NADPH點H(打不出來.....)

功能有何不同?

[♂Freedom 狂 10]

嗯...

我倒沒看過NADPH2的

一般在卡氏都是寫成NADPH+(H離子)吧

因為它是一個...

類似石墨那種不固定接在哪一個的鍵結

所以同時兩個H都有可能接著

才會寫成NADPH+(H離子)

[振瑋 10]

針對你說的NADPH2，我猜你指的是另一種物質：FADH2（一樣要把2變小）

那就把我老師所說的講一下吧，如果沒抄錯（順便複習）～～

針對呼吸作用有四個步驟：

1.醣解作用：作用場所在細胞質，產生2（NADPH＋H*）＋2ATP

2.乙醯輔酶之形成：反應場所在粒線體（的基質內），產生2（NADPH＋H*）

3.克氏循環：作用場鎖在粒線體（的基質內），產生7（NADPH＋H*）＋1（FADH2）＋1ATP

4.電子傳遞鏈：作用場所在粒線體（的內膜上），為產生ATP之過程

所以上述中的ATP有三個，（NADPH＋H*）有十一個，FADH2有一個，而（NADPH＋H*）在電子傳遞鏈中能產生3ATP，FADH2可產生2ATP

相加算一算後有38個ATP

但，實際上在一般細胞行無氧呼吸只會有36個ATP產生，是因為醣解作用完後，2ATP＋2（NADPH＋H*）要穿梭粒線體外膜，會耗能，故在醣解作用時產生的2（NADPH＋H*），進入產生電子傳遞鏈（即產生ATP過程時）時每個（NADPH＋H*）只能產生2ATP

這就是我們的一般說法，在行有氧呼吸時產生36個ATP的緣故

至於某些特殊細胞（如：腎　腦　心）才能擁有38個ATP

其實我對上述說法也有些疑問：（老師是說現階段不用懂那麼多，想懂就去找生物學大百科吧）

為什麼特殊細胞能保有38個ATP？

還有，到底乙醯輔酶之形成，克氏循環和電子傳遞鏈又是如何作用的

希望各位能一起解答看看，謝謝

[starjimmy 10]

There are several points not exactly correct. First of all, "NADH" instead of "NADPH" is used in formed in glycolysis and CAC. You'll see NADPH in pentose phosphate pathway or photosynthesis (related to anabolism anyways.)

Also, according to more correct computation, a molecule of glucose can at best form about 32ATP but in most cell only 30ATP. The difference is due to the energy consumed to transport these products and so on.

Now let's think about why some cells make two more. As mentioned, during the formation of acetylCoA, a molecule of NADH is formed in cytoplasm. This NADH has to be transported into the mitochondria. One way to transport this result in the electrons being fed in to electron transport chain from NADH (as the case in heart and brain.) In most cells, these electrons are fed into the chain in the form of electrons on FADH2. Therefore, there would be two less ATP per mole of glucose.

[noah 10]

what the head going upstairs!!