Credit: Karen Yee, Monell Center.
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Two independent pathways enable taste cells to sense sweet-tasting compounds. The T1R pathway detects both caloric (eg, glucose, sucrose) and non-caloric (eg, saccharin, sucralose) sweet molecules. The T1R-independent 'secondary' pathway senses simple caloric sugars such as glucose and fructose. Disaccharide enzymes in the sweet taste cells break down complex dietary sugars and starch by-products into simple sugars that can activate both pathways.