Topics:
Animal Physiology, Animal Refresher
Products of Lactose Digestion
One mole of lactose on digestion yields:
- Glucose + Glucose
- Glucose + Fructose
- Glucose + Galactose — Correct Answer
- None
Explanation:
Correct Answer: Glucose + Galactose
Lactose is a disaccharide (milk sugar) composed of glucose + galactose linked by a β-1,4-glycosidic bond. Hydrolysis by the enzyme lactase (β-galactosidase) yields one molecule each of glucose and galactose.
Enzyme: Lactase
- Lactase is a brush border enzyme of the small intestinal epithelium (enterocytes).
- High activity in neonates (suckling phase); activity declines after weaning in most mammals — causing lactose intolerance in adult animals.
Comparison of Disaccharide Digestion
- Lactose → Glucose + Galactose (enzyme: Lactase)
- Sucrose → Glucose + Fructose (enzyme: Sucrase)
- Maltose → Glucose + Glucose (enzyme: Maltase)
Nutritional Significance
- Lactose is the primary carbohydrate in milk (~4.7% in cow's milk).
- Galactose is absorbed and converted to glucose in the liver for energy metabolism.
- Lactose intolerance: deficiency of lactase → undigested lactose fermented by colon bacteria → gas, bloating, diarrhea.
📚 About this Topic — Animal Physiology
This multiple choice question is from Animal Physiology, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Physiology to strengthen your preparation.
