Question 1

Which of the following best describes the structural difference between D-glucose and D-fructose as shown in their Fischer projections?

Accepted Answer

D-glucose is a polyhydroxy aldehyde, while D-fructose is a polyhydroxy ketone.

Question 2

Which statement about the D/L system of monosaccharide nomenclature is correct?

Accepted Answer

D and L are assigned based on the configuration of the penultimate carbon relative to D- or L-glyceraldehyde.

Question 3

Which of the following is true regarding mutarotation of D-glucose in aqueous solution?

Accepted Answer

Mutarotation results in an equilibrium mixture of $$\alpha- $$and $$\beta-$$anomers of D-glucose.

Question 4

Which of the following best explains why sucrose does NOT give a positive Benedict’s test?

Accepted Answer

Both anomeric carbons are involved in the glycosidic linkage, so there are no free hemiacetals.

Question 5

Which of the following is a correct description of the glycosidic linkage in amylose?

Accepted Answer

Amylose contains $$\alpha(1,4)$$ glycosidic linkages.

Question 6

Which enzyme deficiency is associated with the symptoms described on the Lactaid box (gas, bloating, diarrhea after dairy consumption)?

Accepted Answer

Lactase

Question 7

Which of the following statements about cellulose is correct?

Accepted Answer

Cellulose is a linear polymer of D-glucose with $$\beta(1,4)$$ linkages.

Question 8

Which of the following best describes the difference between amylopectin and glycogen?

Accepted Answer

Glycogen is more highly branched than amylopectin.

Question 9

Which of the following reactions is used by the liver to detoxify substances containing hydroxyl groups?

Accepted Answer

Formation of glucuronides by conjugation with D-glucuronic acid

Question 10

Which of the following best describes the product formed when D-glucose is treated with methanol and acid?

Accepted Answer

A mixture of $$\alpha- $$and $$\beta-$$methyl D-glucopyranosides (glycosides)

Question 11

Which of the following is a pair of epimers?

Accepted Answer

D-glucose and D-mannose

Question 12

Which of the following best explains why $$\beta-D-$$glucose is more abundant than $$\alpha-D-$$glucose at equilibrium in water?

Accepted Answer

$$\beta-D-$$glucose has less steric hindrance between the anomeric OH and the CH_2OH group.

Question 13

Which of the following statements about the oxidation of monosaccharides is correct?

Accepted Answer

Oxidation with bromine water converts the aldehyde group to a carboxylic acid without affecting alcohol groups.

Question 14

Which of the following best describes the structure of vitamin C (L-ascorbic acid) as related to carbohydrates?

Accepted Answer

It is synthesized from D-glucose and contains an enediol structure.

Question 15

Which of the following best describes the chemical structure of sucralose (a synthetic sweetener)?

Accepted Answer

It is a chlorinated derivative of sucrose.

Question 16

Which of the following is a correct statement about the formation of glycosides from monosaccharides?

Accepted Answer

Glycosides are formed by the reaction of a hemiacetal with an alcohol under acidic conditions.

Question 17

Which of the following best explains why cellulose cannot be digested by humans?

Accepted Answer

Humans lack the enzyme to hydrolyze $$\beta(1,4)$$ glycosidic bonds.

Question 18

Which of the following best describes the process of epimerization?

Accepted Answer

Conversion of one epimer to another by changing the configuration at a single stereocenter.

Carbohydrates: Structure, Classification, and Biological Significance

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