Question

An example of a hydrolysis reaction is a. amino acid \(+\) amino acid \(\rightarrow\) dipeptide \(+\mathrm{H}_{2} \mathrm{O}\). b. dipeptide \(+\mathrm{H}_{2} \mathrm{O} \longrightarrow\) amino acid \(+\) amino acid. c. denaturation of a polypeptide. d. Both b and c are correct.

Short answer

The example of a hydrolysis reaction is given by Option b: Dipeptide + \(H_{2}O\) → amino acid + amino acid.

Step-by-step solution

Option a

Amino acid + amino acid → dipeptide + H₂O. This reaction is a condensation reaction, not a hydrolysis reaction. In a condensation reaction, two molecules combine to form a single molecule, and a water molecule is released in the process.

Option b

Dipeptide + H₂O → amino acid + amino acid. This reaction represents a hydrolysis reaction. Here, a water molecule (H₂O) is used to break the bond between the two amino acids in the dipeptide, resulting in the formation of two separate amino acid molecules.

Option c

Denaturation of a polypeptide. Denaturation of a polypeptide refers to the loss of its structure due to external factors such as heat, pH changes, or chemicals. This process does not involve a hydrolysis reaction because no covalent bonds are broken, and no water molecules are involved in the process.

Option d

Both b and c are correct. As we have analyzed above, only Option b represents a hydrolysis reaction. Therefore, Option d cannot be correct, as it claims that both Option b and Option c are correct. Taking into consideration the analysis of all four options, the correct answer is:

Answer

The example of a hydrolysis reaction is given by Option b: Dipeptide + H₂O → amino acid + amino acid.

Key concepts

Condensation Reaction

In a condensation reaction, two molecules become one larger molecule, and water is released. This forms the backbone of how amino acids, the building blocks of protein, link. Imagine each amino acid as a bead; when you string them together, each link sheds a droplet of water. This removal of water is what we call a condensation reaction. It is essential in forming structures like dipeptides and proteins.
Condensation reactions are not just limited to biological systems; they also occur in many chemical processes.

• These reactions are crucial for creating long chains of molecules, like proteins and polymers.
• Each time a bond forms between two molecules, typically a water molecule is set free.

Understanding condensation reactions helps in comprehending how complex biological molecules are assembled and maintained.

Amino Acids

Amino acids are molecules vital for life, known for being the building blocks of proteins. Each amino acid has an amine group ( -NH₂), a carboxylic acid group ( -COOH), and a unique side chain that gives each one its identity.
Humans utilize 20 different amino acids to construct proteins, each with distinct properties:

• Some amino acids are hydrophobic (water-repelling), while others are hydrophilic (water-attracting).
• They play a role in everything from building tissues to triggering chemical reactions in the body.

When amino acids join together, they can form a peptide bond that results in longer chains known as polypeptides and proteins.
The diversity and function of proteins are directly dependent on the order and type of amino acids involved.

Dipeptides

Dipeptides are the simplest peptides and consist of two amino acids linked by one peptide bond. This linkage occurs through a condensation reaction, where a water molecule is expelled. Think of dipeptides as the initial step in assembling larger protein structures.
Dipeptides have roles beyond just being building blocks for larger proteins:

• They can act as molecules that send messages in the body.
• They help in the transport of smaller peptides and amino acids across cell membranes.

Understanding dipeptides gives insight into how proteins start forming and how the intricate sequences of amino acids influence protein function.

Protein Denaturation

Protein denaturation is when a protein loses its shape due to external stress like heat, chemicals, or pH changes. While this process doesn't break the primary sequence of the protein, it affects the protein's secondary, tertiary, or quaternary structures.
Denaturation changes the protein's functionality, pathway, and its ability to perform biological tasks:

• Denatured proteins can lose their solubility and begin to precipitate out of solution.
• This process can be reversible or irreversible, depending on the severity and type of the denaturing agent.

Despite not involving a hydrolysis reaction, understanding denaturation is crucial because it influences how proteins work and interact within living systems. This concept is central to various applications, like cooking, where the heat denatures protein structures, altering their texture and appearance.