Question

Which among the following carbohydrates is a trisaccharide?

• A. Ribose
• B. Raffinose
• C. Glycogen
• D. Stachyose

Hint:

Remember this straightforward count checklist for oligosaccharides: sucrose/maltose/lactose are disaccharides (2 units), raffinose is a trisaccharide (3 units), and stachyose is a tetrasaccharide (4 units).

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks us to identify the trisaccharide carbohydrate among the choices, which means it will yield exactly three monosaccharide units upon complete hydrolysis.

Step 2: Detailed Explanation:
Carbohydrates are classified by how they break down under hydrolysis:

Ribose: A basic pentose sugar that cannot be broken down further. It is a

monosaccharide.

Raffinose: A crystalline oligosaccharide compound with the formula $\text{C}_{18}\text{H}_{32}\text{O}_{16}$. When hydrolyzed, its chemical structure breaks down cleanly into three distinct simple sugars:
$$ \text{Raffinose} + 2\text{H}_2\text{O} \xrightarrow{\text{hydrolysis}} \text{D-Glucose} + \text{D-Fructose} + \text{D-Galactose} $$ This makes it a classic

trisaccharide.

Glycogen: A highly branched polymer of glucose units that acts as a large energy storage medium. It is a

polysaccharide.

Stachyose: A sugar composed of four monosaccharide subunits (one glucose, one fructose, and two galactoses), classifying it as a

tetrasaccharide.


Step 3: Final Answer: The carbohydrate classified as a trisaccharide is raffinose, matching option (B).