Honey tastes sweet and cotton does not, yet both are built from glucose. We follow the sugars from glucose and fructose to sucrose, starch, cellulose and glycogen: their open and ring forms, their reactions and their optical rotations.
3 lessons, about 1 h 35 min3 simulations10 problems6 practice questionsPython in every lesson
Created by StemPy LabA sugar cube, a slice of bread and a sheet of paper are made of carbohydrates. We sort the carbohydrates into groups, learn to draw a sugar in a Fischer projection, count its stereoisomers, and then see how chemists worked out the structure of glucose.
Glucose has an aldehyde group and five hydroxyl groups, yet it does not behave like a plain aldehyde. The aldehyde and one hydroxyl group close into a ring. The ring comes in two forms, and a solution of one form slowly changes into a mixture of both.
When two sugars join, they lose a molecule of water and make a glycosidic link. Sucrose, maltose and lactose are the common pairs. Starch, cellulose and glycogen are long chains of glucose, and a small change in the link makes one food and another fibre.
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