20. Carbohydrates

Draw the structures of an aldopentose and a ketohexose.

How many chiral carbon atoms are present in each of the molecules shown in Problem 20.31?

How many chiral carbon atoms are present in each of the molecules shown in Problem 20.31?

Draw the open-chain structure of a 4-carbon deoxy sugar.

Draw the structures of a ketohexose.

Draw the Fischer projection for each of the following wedge–dash structures:

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Draw the Fischer projection for each of the following wedge–dash structures:

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An infant with galactosemia can utilize D-glucose in milk but not d-galactose. How does the Fischer projection of D-galactose differ from that of D-glucose?

D-Fructose is the sweetest monosaccharide. How does the Fischer projection of D-fructose differ from that of D-glucose?

What are the differences in the Fischer projections of d-fructose and d-galactose?

On an exam, a student was asked to draw the Fischer projection of l-glucose, but he had only memorized the structure of d-glucose. He wrote the structure of d-glucose and switched the hydroxyl group on C5 from the right to the left. Was his answer correct? If not, what is the name of the aldose that he drew?