Metabolism Metabolism the sum of all of the
代謝(Metabolism) • Metabolism, the sum of all of the enzyme-catalyzed reactions in a living organisms, is highly coordinated and purposeful cell activity. • 。
• Metabolic pathway are promoted by sequential enzyme systems. Enzymes are the simplest units of metabolic activity, each catalyzing a specific chemical reaction. • 代謝途徑是由一個接連一個的酵素作用所 組成的,酵素是代謝活性中最簡單的單位, 每個酵素催化一個特異的化學反應。大部 分的代謝過程是循途徑(pathway)方式進行。
代謝途徑(metabolic pathway)
Catabolism (degradation) • Catabolism: Organic nutrient molecules are degraded by stepwise reactions into smaller, simpler end products. • Catabolism過程常伴隨自由能釋出,但大部分的 自由能是以ATP(energy-carrying molecule)或 以高能的電子即NADH or FADH 2 (energy-rich hydrogen atom)形式儲存。NADH與FADH 2進入呼吸 鏈(respiratory chain)將電子轉移給O 2並伴隨大 量的ATP生成。
Anabolism (biosynthesis) • Anabolism (biosynthesis) : Small precursors or building block molecules are built up into large macromolecular components of cells. • Anobolism過程需輸入自由能包括ATP分解 成phosphate與ADP或AMP並需供給高能的電 子(NADPH)。
Amphibolism • Amphibolism : It serves in both catabolic and anabolic processes. • The citric acid cycle is an amphibolic pathway. It not only functions in the oxidative catabolism of carbohydrate, fatty acids, and amino acids, but also provides precursors for many biosynthetic pathways.
Biosynthetic(Anabolic) pathways diverge to yield many product • 例如許多脂類分子是由acetyl-Co. A衍生而來。
表 13 -2 TABLE 1 -1 p. 526
表 13 -3 TABLE 1 -1 p. 526
Bioenergetics • ATP (adenosine triphosphate) is the universal currency of free energy in biological systems. • 起初ATP被認為與肌肉的活力(activity)有關 (1929),之後陸陸續續的研究發現,它也存在其 他形式的細胞中,而且動、植物與微生物皆存在。 • In 1941, Fritz Lipmann saw the broad significance of these observations and postulated the unifying concept that ATP is the primary and universal carrier of chemical energy in cells.
表 13 -6 TABLE 1 -1 p. 540
u磷醯基從 1, 3 -二磷酸甘油酸轉移到 ADP Phosphoryl Transfer from 1, 3 -Bisphoglycerate to ADP 磷酸甘油酸激酶( phosphoglycerate kinase)把 1, 3 -二磷酸甘油酸羧基上的高能磷醯 基轉移到 ADP ,形成 ATP 和 3 -磷酸甘油酸(3 -phosphoglycerate) : P. 576
BOX 13 -1 螢火蟲的閃爍:ATP 的發光報導 BOX 1 -2 FIGURE 1 p. 544
圖 13 -24 FIGURE 1 -18(a) p. 553
表 13 -8 TABLE 1 -1 p. 554
表 13 -9 TABLE 1 -1 p. 555
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