Can anyone explain exactly where in Carbohydrate ring structure an Aldehyde is?

[MedicalMan14]

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Can anyone explain exactly where in the Carbohydrate ring structure an Aldehyde or Ketone is located so that I can better answer these Benedicts Reagent questions? The reason I ask is that when I visualize the ring structure I cannot seem to see where the Ketone or Aldehyde is? Take for instance Glucose.

 

[BerkReviewTeach]

Can anyone explain exactly where in the Carbohydrate ring structure an Aldehyde or Ketone is located so that I can better answer these Benedicts Reagent questions? The reason I ask is that when I visualize the ring structure I cannot seem to see where the Ketone or Aldehyde is? Take for instance Glucose.

Ring or straight chain form, look for the carbon with TWO bonds to O, and that is your carbon. In glucose C1 is the aldehyde carbon in the straight chain form and the anomeric carbon in the ring form.

 

[docelh]

To visualize, would be green O in the pic.

 

[MedicalMan14]

Ok so I'm confused is the C1-O the derivative of the Ketone or is it the C1-OH?

 

[docelh]

Glucose is an aldehyde at C1. In forming a ring, it undergoes a hemi-acetal reaction, which as you may or may not recall, looks something like this at C1: HO-(HCR)-OR.