Question

Given the molecular weight of Glycine is 75, what would be the molecular weight of Gly-Gly dipeptide?

• A. 150
• B. 250
• C. 132
• D. 321

Hint:

To find the weight of any polymer: (Sum of monomers) - (Number of bonds $\times$ 18).

Answer 1

The Correct Option is C

Step 1: Concept
A dipeptide is formed by the condensation reaction of two amino acids, which involves the removal of one water molecule ($H_{2}O$) to form a peptide bond.

Step 2: Analysis
Molecular weight of Glycine = 75.
Molecular weight of two Glycine molecules = $75 + 75 = 150$.

Step 3: Reasoning
During the formation of the Gly-Gly dipeptide, one molecule of water is lost.
Molecular weight of $H_{2}O = (2 \times 1) + 16 = 18$.

Step 4: Conclusion
Resultant weight = $150 - 18 = 132$. Note: While the text lists 250, the official key (5591) and chemical calculation confirm 132. Final Answer: (C)