AP BIOLOGY

Detailed explanation-1: -Other disaccharides, such as sucrose and lactose are broken down by sucrase and lactase, respectively. Sucrase breaks down sucrose (or “table sugar”) into glucose and fructose, and lactase breaks down lactose (or “milk sugar”) into glucose and galactose.

Detailed explanation-2: -Lactose is a disaccharide found in milk and it consists of a beta-D-galactose that is attached to an alpha-D-glucose. The linkage between these two sugars is a beta-1, 4-glycosidic bond. In humans, lactase breaks down lactose at the brush border of the small intestine.

Detailed explanation-3: -Lactase only breaks down lactose, but not other carbohydrates, such as sucrose or maltose. To measure whether an enzyme is active, scientists can measure the end product(s) of an enzymatic reaction.

Detailed explanation-4: -The digestion of disaccharides and some oligosaccharides is undertaken by a number of small intestinal brush border enzymes: sucrase-isomaltase, lactase phlorizinhydrolase, maltase-glycoamylase and trehalase.

Detailed explanation-5: -Sucrose, or table sugar, is another common sugar composed of glucose and fructose, a five-sided molecule. In this lab, we will use the enzyme lactase to attempt to break down both of these disaccharides. Lactase catalyzes the conversion of lactose to glucose and galactose.