10-minute Quiz : Chapter 56 Natural polymers

Direction: Questions 1 and 2 refer to the chemical structure of glucose, whose molecules are the building blocks of starch and cellulose.

The chemical structure of glucose, represented in open chain form, is shown in the diagram. Which of the following functional groups are present in this form of glucose?

• A. Hydroxyl group and carboxyl group
• B. Hydroxyl group and hydrogen group
• C. Hydroxyl group and ketone group
• D. Hydroxyl group and aldehyde group

Direction: Questions 1 and 2 refer to the chemical structure of glucose, whose molecules are the building blocks of starch and cellulose.

With reference to the structure of glucose shown in the diagram, how many chiral carbon atoms does this form of glucose have?

• A. 3
• B. 4
• C. 5
• D. 6

Part of the structure of cellulose and part of the structure of chitin are shown in the diagram. Which of the following statements concerning the difference in the monomer structures of cellulose and chitin is correct?

• A. The hydroxyl group at the C-2 position in β-glucose is replaced by acetylamino group in N-acetylglucosamine.

• B. The hydroxyl group at the C-3 position in β-glucose is replaced by acetylamino group in N-acetylglucosamine.

• C. The hydroxyl group at the C-4 position in β-glucose is replaced by acetylamino group in N-acetylglucosamine.

• D. The hydroxyl group at the C-5 position in β-glucose is replaced by acetylamino group in N-acetylglucosamine.

Which of the following descriptions concerning the structure of chitin is correct?

• A. Its polymer chains are held together by many strong covalent bonds.
• B. Its polymer chains are held together by many strong hydrogen bonds.
• C. It has a giant covalent structure.
• D. It has a giant lattice structure.

Which of the following statements about cellulose and chitin are correct?

(1) Both of them are made up of glucose-based monomers.

(2) Both of them are important for providing structural support.

(3) Both of them can be found in the cell walls of fungi.

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)

Which of the following statements correctly explains why cellulose is insoluble in water?

• A. Cellulose is a non-polar substance.

• B. Cellulose lacks polar groups in its polymer chains to attract water molecules.

• C. The hydroxyl groups in cellulose polymer chains are less available for forming hydrogen bonds with water molecules.

• D. Cellulose polymer chains form weak hydrogen bonds with water molecules.

Which of the following statements concerning the structure of cellulose are correct?

(1) Ester linkages form between the β-glucose units of cellulose polymer chains.

(2) Polymer chains of cellulose are long, flat and ribbon-like.

(3) Polymer chains of cellulose are held together by intramolecular and intermolecular hydrogen bonds.

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)

Which of the options is the repeating unit of cellulose?

• A
• B
• C
• D

Which of the following are the properties of cellulose?

(1) High tensile strength

(2) Hydrophobic

(3) Biodegradable

• A. (1) and (2) only

• B. (1) and (3) only

• C. (2) and (3) only

• D. (1), (2) and (3)

Which of the following statements correctly explains why chitin is harder than cellulose?

• A. Chitin can form stronger hydrogen bonds between its polymer chains than cellulose.
• B. Chitin can form stronger linkages between its repeating units than cellulose.
• C. Chitin can form harder polymer chains than cellulose.
• D. Chitin can form longer polymer chains than cellulose.