BIOLOGY 1A03 Lecture Notes - Lecture 17: Lactose Intolerance, Fermented Milk Products, Galactosemia

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 1A03
• Professor: Rosa Da Silva

Document Summary

Applied lecture; theme 3 module 1 and 2; dr. da silva; 10 oct 2014. Lactose is commonly found in milk and other products, as a primary source of energy. Lactase (a -galactosidase) hydrolyzes lactose galactose and glucose. Found on apical surface of absorptive intestinal enterocyte cells. In adult mammals, other than humans, lactase production decreases after weaning (weaning- accustom to food other than mother"s milk) 65% of humans have a reduced ability to digest lactose after weaning. Keep lactase gene permanently on to individuals whose ancestors had domesticated dairy animals (dominant trait) occurred randomly in adjacent regulatory gene (mcm6) = advantageous: enhance lct transcription) People with lactase non-persistence have some lactase activity and include some amount of. Ancestors who could digest lactose = higher chance of surviving the gene that promotes lactose lactose in their diet without problems intolerance = naturally selected.