Question 1

Which of the following statements best describes a monosaccharide?

Accepted Answer

An aldehyde or ketone that contains two or more hydroxyl groups and is the simplest form of carbohydrate.

Question 2

Which of the following is NOT a function of carbohydrates in nature?

Accepted Answer

Catalyzing biochemical reactions as enzymes.

Question 3

Which of the following correctly matches the type of glycosidic bond with its description?

Accepted Answer

O-glycosidic bond: Formed between the anomeric carbon and the oxygen atom of an alcohol.

Question 4

Which of the following is a reducing sugar and why?

Accepted Answer

Glucose, because its open-chain form can react with oxidizing agents.

Question 5

Which statement about the ring forms of monosaccharides is correct?

Accepted Answer

The pyranose form is a six-membered ring found in glucose.

Question 6

Which of the following best explains why phosphorylation of sugars is important in metabolism?

Accepted Answer

Phosphorylation makes sugars anionic, preventing them from leaving the cell and facilitating their metabolism.

Question 7

Which of the following correctly describes the difference between amylose and amylopectin?

Accepted Answer

Amylose contains only $$\alpha-1$$,4-glycosidic bonds, while amylopectin contains both $$\alpha-1$$,4 and $$\alpha-1$$,6-glycosidic bonds.

Question 8

A patient with Hurler's disease is unable to degrade proteoglycans. Which of the following best explains the biochemical basis of this disease?

Accepted Answer

A defect in enzymes required for the degradation of glycosaminoglycans leads to their accumulation.

Question 9

Which of the following statements about glycoproteins is TRUE?

Accepted Answer

Mucins are glycoproteins with carbohydrate attached to the protein by N-acetylgalactosamine.

Question 10

Which amino acid residues are commonly involved in linking carbohydrates to proteins in glycoproteins?

Accepted Answer

Asparagine, serine, and threonine

Question 11

Which of the following best describes the role of lectins in biological systems?

Accepted Answer

Lectins are specific carbohydrate-binding proteins that promote cell-cell interactions.

Question 12

Which of the following is TRUE regarding the blood group antigens?

Accepted Answer

Type A blood group is characterized by the addition of N-acetylgalactosamine to the O antigen.

Question 13

Which of the following is a correct statement about cellulose and its structure?

Accepted Answer

Cellulose is a homopolymer of glucose units linked by $$\beta-1$$,4-glycosidic bonds, forming straight chains.

Question 14

Which of the following is a consequence of improper glycosylation in I-cell disease?

Accepted Answer

Lysosomal enzymes are secreted into the blood instead of being targeted to lysosomes.

Question 15

Which enzyme is responsible for catalyzing the formation of glycosidic bonds during oligosaccharide assembly?

Accepted Answer

Glycosyltransferase

Question 16

Which of the following modifications is commonly found in glycosaminoglycans and contributes to their negative charge?

Accepted Answer

Presence of carboxylate or sulfate groups on amino sugar derivatives

Question 17

Which of the following statements about chitin is correct?

Accepted Answer

Chitin is a glycosaminoglycan found in the exoskeleton of insects and is composed of repeating units of N-acetylglucosamine.

Question 18

Which of the following best explains why soluble fiber, such as pectin, is beneficial in the human diet?

Accepted Answer

It facilitates absorption of nutrients by slowing digestion.

Question 19

A diabetic patient has elevated levels of glycosylated hemoglobin (HbA1c). Which biochemical property of glucose allows this modification to occur?

Accepted Answer

Glucose is a reducing sugar and its open-chain form can react with amino groups on hemoglobin.

Biochemistry Chapter 11: Carbohydrates – Structure, Function, and Biochemical Roles

Guida di studio - Domande di pratica