Question 1

Which of the following statements best explains why humans cannot digest cellulose, even though it is composed of glucose monomers?

Accepted Answer

Humans lack the enzyme to hydrolyze the $$\beta(1 \rightarrow 4)$$ glycosidic linkages between glucose units in cellulose.

Question 2

Which glycosidic linkage is found in lactose, and which enzyme is responsible for its hydrolysis in humans?

Accepted Answer

Lactose contains a $$\beta(1 \rightarrow 4)$$ linkage between galactose and glucose, hydrolyzed by lactase.

Question 3

A patient is diagnosed with lactose intolerance. Which biochemical explanation best describes this condition?

Accepted Answer

The patient lacks sufficient lactase enzyme to hydrolyze the $$\beta(1 \rightarrow 4)$$ glycosidic bond in lactose.

Question 4

Which of the following is a major structural difference between amylose and cellulose?

Accepted Answer

Amylose has $$\alpha(1 \rightarrow 4)$$ glycosidic linkages, while cellulose has $$\beta(1 \rightarrow 4)$$ glycosidic linkages.

Question 5

Which enzyme is responsible for hydrolyzing $$\alpha(1 \rightarrow 4)$$ glycosidic linkages in starch during digestion?

Accepted Answer

Amylase

Question 6

Glycogen and amylopectin are both branched polymers of glucose. Which statement correctly describes a difference in their branching patterns?

Accepted Answer

Glycogen has $$\alpha(1 \rightarrow 6)$$ branches every 8–12 glucose residues, while amylopectin has branches every 24–30 residues.

Question 7

Which of the following best describes the role of glycosidases in carbohydrate metabolism?

Accepted Answer

Glycosidases selectively hydrolyze glycosidic linkages based on stereochemistry and position of the linkage.

Question 8

Which process is used industrially to convert glucose syrup into high fructose corn syrup (HFCS)?

Accepted Answer

Enzymatic isomerization of D-glucose to D-fructose using glucose isomerase.

Question 9

Which of the following is a function of oligosaccharides attached to proteins or lipids as glycoconjugates?

Accepted Answer

They provide unique molecular 'fingerprints' for cell recognition.

Question 10

Which of the following best explains why amylose is water-soluble while cellulose is not?

Accepted Answer

Amylose forms more intramolecular hydrogen bonds with water due to its helical structure, while cellulose forms extensive intermolecular hydrogen bonds between chains.

Question 11

A scientist is studying a polysaccharide composed of repeating disaccharide units, one of which is N-acetylglucosamine and the other is a uronic acid. Which class of biomolecule is being studied?

Accepted Answer

Glycosaminoglycan

Question 12

Which of the following statements about glycosidic linkages is correct?

Accepted Answer

The stereochemistry ($$\alpha or$$ $$\beta) $$and position of the glycosidic bond determine the properties and digestibility of the carbohydrate.

Question 13

Which enzyme is responsible for hydrolyzing the $$\alpha(1 \rightarrow 6)$$ glycosidic linkages in amylopectin?

Accepted Answer

Isomaltase

Question 14

Which of the following is a heteropolysaccharide found in bacterial cell walls, consisting of alternating N-acetylglucosamine and N-acetylmuramic acid units?

Accepted Answer

Peptidoglycan

Question 15

Which of the following best describes the tertiary structure of a carbohydrate macromolecule?

Accepted Answer

The overall three-dimensional fold or shape of the molecule, including interactions between distant regions of the chain.

Question 16

Which of the following is a correct statement about lectins?

Accepted Answer

Lectins are carbohydrate-binding proteins that mediate cell-cell recognition and signaling.

Question 17

Which of the following is a consequence of the diversity of oligosaccharide structures in glycoconjugates?

Accepted Answer

Cells can encode complex information for recognition, signaling, and targeting.

Question 18

Which of the following is a correct description of the process by which excess glucose is stored in animals?

Accepted Answer

Excess glucose is stored as glycogen, a branched polymer of glucose with $$\alpha(1 \rightarrow 4)$$ main chain and $$\alpha(1 \rightarrow 6)$$ branches.

Question 19

Which of the following best explains the importance of glycomics in modern biochemistry?

Accepted Answer

Glycomics allows for the systematic characterization of all carbohydrate components in a cell or tissue, aiding in understanding cell signaling and development.

Carbohydrates: Structure, Glycosidic Linkages, and Biological Roles

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