Question

Pepsin digests
A. Proteins in stomach
B. Carbohydrates in the duodenum
C. Proteins in the duodenum
D. Fats in the ileum

Answer 1

Hint: An endopeptidase called pepsin regulates the function of catabolism of proteins in smaller units called peptides. It is one of the main digestive enzymes of the digestive system of many animals and humans. Pepsin is one of the three main proteases in the digestive system of the human

Complete answer: The human digestive system also called as the alimentary canal or gastrointestinal canal comprises the following organs: mouth, oesophagus, pharynx, stomach, small intestine, large intestine, anus, and accessory organs.
i. Mouth: It is the part of the alimentary canal where the bolus of food is ingested, crushed, and chewed with the help of teeth and tongue. Breakdown of carbohydrates takes place in the mouth with the help of enzyme salivary amylase.
ii. Pharynx: It is part of both the respiratory system and the digestive system. Its role is to conduct food to the oesophagus. iii. Esophagus: It is a muscular tube that runs from the pharynx to the stomach and is also called a food pipe. The food is conducted to the stomach via oesophagus by a process called peristalsis.
iv. Stomach: it is a J-shaped organ with oesophagus located above it and the duodenum located at the lower end. Here, the churning of food takes place. Digestion of protein takes place in the stomach with the help of enzyme pepsin. The Pepsinogen secreted by the chief cells of the stomach lining mixes with the gastric juice and hydrochloric acid, which activates and converts pepsinogen into pepsin. Pepsin regulates the digestion of proteins in the stomach.
v. Small intestine: The food received from the stomach is partially digested and is in a semi-liquid form known as chyme. The small intestine is further divided into 3 parts: duodenum, jejunum, and ileum. The remaining waste exhausted of nutrients is converted into semi-solids known as faeces.
vi. Large intestine: Here, the absorption of remaining minerals and water takes place, and the faeces is pushed into the rectum by the peristalsis movement and is finally expelled through the anus.
So, option A is the correct answer.

Note: Other than digestive organs, accessory organs also play a vital role in the digestion of food. Accessory organs are as follows: tongue, salivary gland, pancreas, liver and gallbladder. These organs secrete digestive juices and enzymes which are necessary for the digestion of food. Saliva, amylase and lipase are secreted by salivary gland. Bile is produced by liver and pancreas secrete pancreatic juices.