Question

Given below are two statements: Statement I: Sucrose consists of \(\alpha\)-D-glucose and \(\beta\)-D-fructose units. Statement II: Lactose consists of \(\beta\)-D-galactose and \(\beta\)-D-glucose units.

• A. Both Statement I and Statement II are correct.
• B. Statement I is correct but Statement II is incorrect.
• C. Statement I is incorrect but Statement II is correct.
• D. Both Statement I and Statement II are incorrect.

Hint:

Remember: \[ \text{Sucrose} = \text{Glucose + Fructose} \] \[ \text{Lactose} = \text{Galactose + Glucose} \] \[ \text{Maltose} = \text{Glucose + Glucose} \]

Answer 1

The Correct Option is A

Step 1: Understand disaccharides.
A disaccharide is made of two simple sugar units joined by a glycosidic link. Different disaccharides use different sugar pairs.

Step 2: Look at sucrose.
Sucrose (table sugar) is built from one glucose unit and one fructose unit.

Step 3: Check the forms in sucrose.
In sucrose the glucose is the $\alpha$-D form and the fructose is the $\beta$-D form, joined by an $\alpha,\beta$ linkage. So Statement I is correct.

Step 4: Look at lactose.
Lactose (milk sugar) is built from one galactose unit and one glucose unit.

Step 5: Check the forms in lactose.
In lactose the galactose is the $\beta$-D form and the glucose is the $\beta$-D form. So Statement II is correct.

Step 6: Combine the results.
Both Statement I and Statement II describe the sugars correctly.

Step 7: State the final answer.
The correct choice is:
\[ \boxed{\text{Both Statement I and Statement II are correct.}} \]