Question

How many chiral centers are present in D-glucose? in D-ribose?

Short answer

Answer: D-glucose has four chiral centers, and D-ribose has three chiral centers.

Step-by-step solution

Identify D-glucose structure

D-glucose is a simple sugar with the molecular formula C6H12O6. It is an aldohexose, which means it has an aldehyde functional group on carbon 1 and five hydroxyl groups attached to a six-carbon straight chain. The structure of D-glucose is as follows: HOCH2-(CHOH)_4-CHO

Identify D-ribose structure

D-ribose is a simple sugar with the molecular formula C5H10O5. It is an aldopentose, meaning it has an aldehyde functional group on carbon 1 and four hydroxyl groups attached to a five-carbon straight chain. The structure of D-ribose is as follows: HOCH2-(CHOH)_3-CHO

Count chiral centers in D-glucose

To count the chiral centers in D-glucose, look at each carbon atom and determine if it has four different groups attached. Remember, a chiral carbon atom should possess four different substituents. In D-glucose, carbon atoms 2, 3, 4, and 5 each have four different groups attached: H, OH, another carbon, and the chain of other atoms. Therefore, D-glucose has four chiral centers.

Count chiral centers in D-ribose

Similarly, to count the chiral centers in D-ribose, look at each carbon atom and determine if it has four different groups attached. In D-ribose, carbon atoms 2, 3, and 4 each have four different groups attached: H, OH, another carbon, and the chain of other atoms. Therefore, D-ribose has three chiral centers. In conclusion, D-glucose has four chiral centers, and D-ribose has three chiral centers.