Match the items in List I with the items in List II
List I                                                     List II
A. Sucrose                                            I. 𝛽-glycosidic link (D-glucose)
B. Lactose                                            II. 𝛼-glycosidic link (D-glucose)
C. Maltose                                           III. 𝛽-glycosidic link (D-glucose and D-galactose)
D. Cellobiose                                      IV. 𝛼-1, 𝛽-2-glycosidic link(D-glucose and D-fructose)
Choose the correct answer from the options given below:
A. A-II, B-IV, C-I, D-III
B. A-I, B-III, C-IV, D-II
C. A-III, B-II, C-I, D-IV
D. A-IV, B-III, C-II, D-I

Match the Disaccharides with Their Glycosidic Bonds

If you’re studying carbohydrates, disaccharides and their glycosidic linkages are essential concepts in biochemistry. This MCQ-type question is designed to help you master the structural differences among sucrose, lactose, maltose, and cellobiose.

Match the Items:

List I – Disaccharides:

• A. Sucrose
• B. Lactose
• C. Maltose
• D. Cellobiose

List II – Glycosidic Link Types:

• I. 𝛽-glycosidic link (D-glucose)
• II. 𝛼-glycosidic link (D-glucose)
• III. 𝛽-glycosidic link (D-glucose and D-galactose)
• IV. 𝛼-1, 𝛽-2-glycosidic link (D-glucose and D-fructose)

Options:

• A. A-II, B-IV, C-I, D-III
• B. A-I, B-III, C-IV, D-II
• C. A-III, B-II, C-I, D-IV
• ✅ D. A-IV, B-III, C-II, D-I

Correct Answer: ✅ D. A-IV, B-III, C-II, D-I

Let’s understand why each pair matches correctly.

🔸 A. Sucrose → IV. 𝛼-1, 𝛽-2-glycosidic link (D-glucose and D-fructose)

Sucrose is made of D-glucose and D-fructose joined by an 𝛼-1 to 𝛽-2 linkage. It’s a non-reducing sugar because both anomeric carbons are involved in the bond.

🔸 B. Lactose → III. 𝛽-glycosidic link (D-glucose and D-galactose)

Lactose is composed of D-galactose and D-glucose linked by a 𝛽-1,4-glycosidic bond. This is a reducing sugar.

🔸 C. Maltose → II. 𝛼-glycosidic link (D-glucose)

Maltose consists of two D-glucose units connected via an 𝛼-1,4-glycosidic bond. It’s produced during the breakdown of starch.

🔸 D. Cellobiose → I. 𝛽-glycosidic link (D-glucose)

Cellobiose also has two glucose molecules, but linked via a 𝛽-1,4-glycosidic bond, unlike maltose.

Key Takeaways

• Sucrose is unique: it’s a non-reducing sugar with a dual anomeric linkage (𝛼-1, 𝛽-2).
• Lactose and Cellobiose both have 𝛽-linkages, but with different sugar pairs.
• Maltose and cellobiose differ only by 𝛼 vs. 𝛽 glycosidic orientation.