Question

In a protein molecule various amino acids are linked together by:

• A. $\beta$-glycosidic bond
• B. peptide bond
• C. dative bond
• D. $\alpha$-glycosidic bond

Answer 1

The Correct Option is B

The question tests your understanding of how amino acids are linked together in a protein molecule. Amino acids, which are the building blocks of proteins, are linked through a specific type of covalent bond known as a peptide bond.

1. Understanding Peptide Bonds: In biochemistry, a peptide bond is formed between the carboxyl group of one amino acid and the amino group of another, releasing a molecule of water (H₂O). This type of bond is specifically termed a -\text{CO-NH}- linkage.
2. Formation of Peptide Bonds: The formation of a peptide bond during protein synthesis involves a condensation reaction. Here, one amino acid's carboxyl group reacts with the amino group of the next amino acid. This reaction forms the peptide chain, also known as a polypeptide chain when multiple amino acids are linked.
3. Explanation of Other Options:
   • $\beta$-glycosidic bond: This type of bond is not involved in linking amino acids. It pertains to the linkage between sugar molecules in carbohydrates.
   • Dative bond: Also known as a coordinate bond, this type of bond involves the sharing of a pair of electrons between atoms, but it is not specific to the formation of peptide chains in proteins.
   • $\alpha$-glycosidic bond: Like the $\beta$-glycosidic bond, this bond is specific to carbohydrate molecules, connecting two sugar units.
4. Conclusion: The correct answer is that amino acids in protein molecules are linked by peptide bonds.

Therefore, the correct option is: peptide bond