The stones present in the gall bladder affect the digestion of:

The correct answer is B) Fat. Bile is made in the liver, stored and concentrated in the gall bladder, and released into the duodenum after a fatty meal. Bile salts emulsify fat, breaking large globules into tiny droplets so that pancreatic lipase can act on them. When gallstones block the cystic or common bile duct, bile flow drops, fat emulsification becomes poor, and fat malabsorption (steatorrhoea) can follow.

• Protein (A): Proteins are broken down mainly by pepsin in the stomach and by trypsin, chymotrypsin and peptidases from the pancreas. Bile has no direct enzymatic role here.
• Carbohydrate (C): Salivary amylase and pancreatic amylase digest starch. Bile is not needed for this.
• Nucleic acid (D): Pancreatic nucleases such as ribonuclease and deoxyribonuclease, along with intestinal enzymes, digest nucleic acids.

Core concept: the role of bile in lipid digestion. It links to the Biology topic on human physiology and to Mains questions on diet-linked lifestyle diseases.

Trap: Students sometimes pick Protein because bile and pancreatic juice are grouped together as 'digestive juices'. Remember that bile has no protease activity; its job is emulsification of fats.