MCQ Detailed View

The human body obtains energy and essential building materials from the food we eat. Food contains major nutrients, including carbohydrates, fats, proteins, vitamins, and minerals. Among these, proteins are crucial for the growth, repair, and maintenance of body tissues. However, proteins cannot be absorbed by the body in their complex form. They need to be broken down into their simplest building blocks known as amino acids.

During digestion, proteins undergo both mechanical and chemical processes. The process begins in the stomach, where an enzyme called pepsin (activated by gastric acid) starts breaking down large protein molecules into smaller chains called peptides. This process continues in the small intestine, where other enzymes such as trypsin, chymotrypsin, and peptidases further break down peptides into individual amino acids.

Once amino acids are formed, they are absorbed through the lining of the small intestine into the bloodstream. The body then uses these amino acids to build new proteins, produce enzymes, hormones, and antibodies, and repair damaged cells and tissues. Amino acids are therefore often referred to as the building blocks of life.

Other nutrients like carbohydrates are broken down into simple sugars (glucose), while fats are digested into fatty acids and glycerol. Vitamins are not digested but are absorbed directly because they are already in simple form. Hence, only proteins produce amino acids as their end products during digestion.

Understanding this process is an essential concept in Biology, especially in the study of human physiology and nutrition. It highlights how our body converts complex food molecules into simple, usable forms necessary for growth, energy production, and overall health.