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: Understand the question.
We must pick the trisaccharide, a sugar that breaks into exactly three simple sugar units on full hydrolysis.

Step 2: Check ribose.
Ribose is a single five carbon sugar that cannot be broken down further. It is a monosaccharide, so not the answer.

Step 3: Check glycogen.
Glycogen is a very large branched chain made of many glucose units. It is a polysaccharide, so not the answer.

Step 4: Check stachyose.
Stachyose breaks into four sugar units, so it is a tetrasaccharide, not a trisaccharide.

Step 5: Check raffinose.
Raffinose breaks down into exactly three simple sugars: glucose, fructose, and galactose.
\[ \text{Raffinose} \rightarrow \text{Glucose} + \text{Fructose} + \text{Galactose} \]
Three units means it is a trisaccharide.

Step 6: Pick the answer.
The trisaccharide is raffinose, which is option 2.
\[ \boxed{\text{Raffinose}} \]