Amino acids are obtained from proteins by

Step 1: Analyze the question The question asks which process breaks proteins down to give amino acids.

Step 2: Explain the concept Proteins are polymers made of many amino acid units joined by peptide (amide) bonds (–CO–NH–). To get the amino acids back, these bonds must be broken.

The reaction that breaks bonds using water is hydrolysis:

Protein + water → (acid, alkali, or enzyme) → amino acids

In the body, enzymes such as pepsin and trypsin catalyse this process during digestion. In the lab, you can boil the protein with dilute acid such as HCl.

Step 3: Check each option

• A. Hydrolysis: Water breaks the peptide bonds and releases free amino acids. ✔
• B. Oxidation: This involves the addition of oxygen or loss of electrons. It does not break peptide bonds to give amino acids.
• C. Polymerization: This is the opposite process. Amino acids join together to form proteins.
• D. Reduction: This involves the addition of hydrogen or gain of electrons. It is not the way proteins are broken down.

Step 4: Answer The correct option is **A.

Exam tip: Remember that "lysis" means "breaking," so hydro-lysis means "breaking with water." Polymerization builds big molecules, while hydrolysis breaks them down. Similar examples are starch → glucose, fats → fatty acids and glycerol, and proteins → amino acids.