91Ó°ÊÓ

What are the differences in the Haworth structures of $\mathrm{Î\pm }$-D-glucose and $\mathrm{β}$-D-glucose? (13.4)

The sugar D-gulose is a sweet-tasting syrup. (13.3, 13.4)

a. Draw the Fischer projection for L-gulose.

b. Draw the Haworth structures for $\mathrm{Î\pm }$- and $\mathrm{β}$-D-gulose.

What are the functional groups and number of carbons in a ketopentose?

Use the Fischer projection for D-gulose in problem $13.69$to answer each of the following: $(13.3,13.5)$

a. Draw the Fischer projection and name the product formed by the reduction of D-gulose.

b. Draw the Fischer projection and name the product formed by the oxidation of D-gulose.

D-Sorbitol, a sweetener found in seaweed and berries, contains only hydroxyl functional groups. When D-sorbitol is oxidized, it forms D-glucose. Draw the Fischer projection for D-sorbitol.$(13.3,13.5)$

D-Erythritol is$70\%$ as sweet as sucrose and contains only hydroxyl functional groups. When D-erythritol is oxidized it forms D-erythrose. Draw the Fischer projection for D-erythritol.$(13.3,13.5)$

If $\mathrm{Î\pm }\mathit{-}$galactose is dissolved in water,$\mathrm{β}\mathit{-}$galactose is eventually present. Explain how this occurs. (13.5)

Why are lactose and maltose reducing sugars, but sucrose is not? (13.6)

$\mathrm{Î\pm }$-Cellobiose is a disaccharide obtained from the hydrolysis of cellulose. It is quite similar to maltose except it has a $\mathrm{β}(1→4)$-glycosidic bond. Draw the Haworth structure for$\mathrm{Î\pm }-$cellobiose. (13.4, 13.6)

The disaccharide trehalose found in mushrooms is composed of two $\mathrm{Î\pm }$-D-glucose molecules joined by an $\mathrm{Î\pm }(1→1)$-glycosidic bond. Draw the Haworth structure for trehalose. (13.4,13.6)