Carbohydrates Knowledge-Based Practice

Questions

1. 1.

   Which compound is formed as the major organic product when D-glucose is treated with bromine water ($\text{Br}_2/\text{H}_2\text{O}$)?

   • A) D-Glucaric acid
   • B) D-Glucitol
   • C) D-Glucuronic acid
   • D) D-Gluconic acid
2. 2.

   Treatment of D-glucose with excess methanol in the presence of an anhydrous acid catalyst yields a mixture of methyl $\alpha$-D-glucopyranoside and methyl $\beta$-D-glucopyranoside. Which statement correctly describes the chemical behavior of these resulting methyl glucosides?

   • A) They readily undergo mutarotation when dissolved in neutral aqueous solution.
   • B) They act as reducing sugars toward Tollens' reagent in basic aqueous solution.
   • C) They exist in rapid dynamic equilibrium with an open-chain aldehyde form in water.
   • D) They are stable cyclic acetals that do not undergo mutarotation in neutral aqueous solution.
3. 3.

   Which of the following pairs of monosaccharides represents C-4 epimers?

   • A) D-glucose and D-mannose
   • B) D-glucose and D-galactose
   • C) D-glucose and D-fructose
   • D) D-glucose and L-glucose
4. 4.

   Which of the following statements correctly identifies the primary structural difference between cellulose and amylose?

   • A) Cellulose consists of D-glucose units linked by $\beta$-(1$\rightarrow$4)-glycosidic bonds, whereas amylose consists of D-glucose units linked by $\alpha$-(1$\rightarrow$4)-glycosidic bonds.
   • B) Cellulose is a branched polymer containing $\alpha$-(1$\rightarrow$6)-glycosidic linkages, whereas amylose is entirely unbranched with $\beta$-(1$\rightarrow$4)-glycosidic linkages.
   • C) Cellulose is a heteropolysaccharide composed of alternating D-glucose and D-galactose units, whereas amylose is a homopolysaccharide of D-glucose.
   • D) Cellulose consists of D-fructose units joined by $\beta$-(2$\rightarrow$1)-glycosidic bonds, whereas amylose is composed of D-glucose units joined by $\alpha$-(1$\rightarrow$4)-glycosidic bonds.
5. 5.

   Which of the following disaccharides is classified as a non-reducing sugar because both of its anomeric carbon atoms participate in the glycosidic bond?

   • A) Maltose
   • B) Lactose
   • C) Cellobiose
   • D) Sucrose

Answers and step-by-step solutions appear after you finish the test.