Starch & Cellulose

Superman

2008-06-06 7:04 am

睇書果陣睇到starch properties :
" the chain is coiled into a helix forming a cylinder in which most of the hydroxyl group , capable of forming cross linkage projection into the interior . Because no cross-linkage can be formed between starch molecules , it lacks structural properties. "

1. most of the hydroxyl group , capable of forming cross linkage projection into the interior 即係咩意思? 可以用中文explain嗎?

2. 點解starch同starch之間無cross-linkage ?

3. 點解glycogen is more soluble than starch ?

" The orientation of the molecule cause the OH - groups to stick outward frome the chain in all directions . These chains form hydrogen bonds with neighbouring chains thereby establishing a 3-dimensional lattice . "

1. 其實呢句野意思係咩? 可以用中文explain嗎?

2. 咩野係 3-dimensional lattice ?

回答 (1)

FluorescentProtein G

2008-06-06 7:58 am

✔ 最佳答案

most of the hydroxyl group , capable of forming cross linkage projection into the interior 即係starch chain 在空间呈螺旋状结构，好似卷圈電話繩，淀粉螺旋中央空穴-OH gps 全向內可form cross link.淀粉是植物贮存能量的一种方式
starch同starch之間無cross-linkage, 它自己已卷成一團，唔會同隔來個starch link喇。
glycogen由葡萄糖失水縮合作用而成。结构与支链淀粉相似，由α—1，4-糖苷键和支链连接处的α—1，6-糖苷键连接而成。与支链淀粉在结构上的主要区别在于，糖原的支链多大约8~12个葡萄糖就有一个分支（支链淀粉一般是每隔24~30个葡萄糖才有一个分支）且分支有12~18个葡萄糖分子。

2008-06-06 00:06:28 補充：
3-dimensional lattice 直譯就是三維空間的格仔，說的是－OH groups 全向內，與上下左右相鄰的－OH form H-bond, 形成三維空間的格仔式的bonds, 所以應該很stable.

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