Question 1

Which of the following statements best describes a chiral molecule?

Accepted Answer

A molecule whose mirror image is not superimposable on the original molecule.

Question 2

How many possible stereoisomers exist for a molecule with three stereocenters?

Accepted Answer

$$2^3 = 8$

Question 3

Which of the following best explains why enantiomers of a drug like ibuprofen can have different biological activities?

Accepted Answer

Enantiomers interact differently with chiral biological molecules such as enzymes and receptors.

Question 4

A carbohydrate with the formula $$C_6H_{12}O_6$ is classified as which of the following?

Accepted Answer

Monosaccharide

Question 5

Which of the following statements about Fischer projections is correct?

Accepted Answer

Horizontal lines represent bonds coming out of the plane of the page.

Question 6

Which of the following best describes a diastereomer?

Accepted Answer

A stereoisomer that is not a mirror image of another molecule.

Question 7

Which of the following is true regarding the optical activity of chiral molecules?

Accepted Answer

Chiral molecules rotate plane-polarized light, and the direction of rotation is used to distinguish between enantiomers.

Question 8

A sugar that contains a five-membered ring is called a:

Accepted Answer

Furanose

Question 9

Which of the following best describes mutarotation?

Accepted Answer

The interconversion between $$\alpha$$ and $$\beta$$ anomers of a sugar in solution.

Question 10

Which of the following is a correct statement about glycosidic bonds in polysaccharides?

Accepted Answer

Glycosidic bonds can form between any hydroxyl group of one monosaccharide and the anomeric carbon of another.

Question 11

A patient with lactose intolerance is unable to digest lactose because they lack which enzyme?

Accepted Answer

Lactase

Question 12

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 present in cellulose.

Question 13

Which of the following is a correct description of an anomer?

Accepted Answer

A type of stereoisomer that differs only at the anomeric carbon in a cyclic sugar.

Question 14

Which of the following is a correct statement about the structure of glycogen?

Accepted Answer

Glycogen is a branched polymer of glucose with branches every 8-12 glucose units.

Question 15

A molecule of D-glucose in solution can exist in several forms. Which of the following is the most abundant form under physiological conditions?

Accepted Answer

$$\beta-D-$$glucopyranose

Question 16

Which of the following best describes the difference between a homopolysaccharide and a heteropolysaccharide?

Accepted Answer

Homopolysaccharides contain only one type of monosaccharide unit, while heteropolysaccharides contain two or more types.

Question 17

Which of the following is a correct application of the $$2^n$$ rule for stereoisomers?

Accepted Answer

A molecule with 4 stereocenters will have $$2^4 = 16$ possible stereoisomers.

Question 18

Which of the following best describes the function of glycoproteins?

Accepted Answer

They are oligosaccharides linked to proteins and play roles in cell recognition and signaling.

Question 19

Which of the following is a correct statement about the difference between $$\alpha$$ and $$\beta$$ anomers of glucose?

Accepted Answer

The $$\alpha$$ anomer has the OH group on the anomeric carbon trans to the CH$$_2OH $$group, while the $$\beta$$ anomer has it cis.

Ch. 15: Carbohydrates and Stereochemistry: Structure, Isomerism, and Biological Relevance

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