Ketose, Aldose, Furanose, Pyranose

[MedPR]

I know the terms have something to do with the 5-membered rings of carbohydrates, but I'm not exactly sure what they are or how they are related.

Could someone give me a brief overview of what they are in terms of MCAT?

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[chiddler]

I know the terms have something to do with the 5-membered rings of carbohydrates, but I'm not exactly sure what they are or how they are related.

Could someone give me a brief overview of what they are in terms of MCAT?

Furanose = 5 carbon sugar.
Pyranose = 6 carbon sugar.
Ketose = ketone containing sugar like fructose
Aldose = aldehyde containing sugar like glucose

It's covered in part II biology of berkeley review.

 

[Ssina]

I think as far as it goes for the mcat, you just have to recognize them if they give you these as a figure, but all I know is that:

aldoses have the aldehyde functional group at C#1, e.g. on Glucose, when looking at it's Fischer projection
ketoses have the ketone at C#2, e.g. fructose

as the result, when they go under cyclization (to Haworth projection) aldoses form a pyranose (a 6 membered ring) and ketoses form a furanose (5 member ring).

i'm sure others can add more details, but this is all I know!