Biochemistry -- Dissacharides, Etc.

[sciencebooks]

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Hey guys, sorry to go on about "oh-my-gosh-what-do-I-need-to-know" but, as always, your advice is most helpful, 🙂.

Which sugars did you all memorize?

I've just committed to memory the monomers (glucose, fructose, and galactose), more obviously, and four dissacharides (cellobiose, maltose, lactose, and sucrose) -- what monomers they're made of and linkage.

Is there anything more I should know or any other important dissacharide?

Thanks!

 

[ebasappa]

I'm pretty sure you have all the correct ones memorized, TBR suggests you also memorize Ribose and Mannose too. If you don't already, I would give the hawthorne projection a good read. Good luck!

 

[circulus vitios]

What are you memorizing, the structures?

 

[sciencebooks]

What are you memorizing, the structures?

Nooo. I think the book suggests just knowing like "maltose is 1,4 alpha glucose-glucose" and so on.

For structures, I was always told to only know D-glucose?

 

[Jengreef]

Structures actually aren't that bad. TBR gave some excellent memory aids for glucose, galactose, manose, ribose, and fructose. In a Fischer projection, penultimate carbon's OH points right if D and left if L, so using your right hand, you actually can form easy to remember carbohydrate forms for the ones I mentioned above. The OH groups point in the direction of the tips of your fingers:

http://desmond.imageshack.us/Himg88/scaled.php?server=88&filename=62477176.png&res=landing

Also, to convert to Haworth, an OH group that points right in the Fischer projection points down in the Haworth, and left points up "downright uplefting". The anomeric carbon's OH (which is the carbonyl oxygen in the Fischer projection I think) is trans to the last carbon's OH if the sugar is alpha, and cis to the last carbon's OH if the sugar is beta. This also determines the type of linkage in di and polysaccharides. The penultimate carbon's O (the one that identifies D or L sugars) is the O that's part of the ring in Haworth.

I think I said everything right, but someone correct me if I'm not. lol

 

[sciencebooks]

Structures actually aren't that bad. TBR gave some excellent memory aids for glucose, galactose, manose, ribose, and fructose. In a Fischer projection, penultimate carbon's OH points right if D and left if L, so using your right hand, you actually can form easy to remember carbohydrate forms for the ones I mentioned above. The OH groups point in the direction of the tips of your fingers:

http://desmond.imageshack.us/Himg88/scaled.php?server=88&filename=62477176.png&res=landing

Also, to convert to Haworth, an OH group that points right in the Fischer projection points down in the Haworth, and left points up "downright uplefting". The anomeric carbon's OH (which is the carbonyl oxygen in the Fischer projection I think) is trans to the last carbon's OH if the sugar is alpha, and cis to the last carbon's OH if the sugar is beta. This also determines the type of linkage in di and polysaccharides. The penultimate carbon's O (the one that identifies D or L sugars) is the O that's part of the ring in Haworth.

I think I said everything right, but someone correct me if I'm not. lol

Hahaha, I actually just memorized all that back in orgo without those mnemonics. I knew the middle finger for glucose but the gun one is funny, 😛. Thanks.

 

[Sandstorm]

I never memorized or needed any of the structures or any of this stuff. Just know how to choose d versus L