Lactase is an enzyme that breaks down lactose (milk sugar) into glucose and galactose. It is embedded in the luminal plasma membranes of intestinal epithelial cells, where it is involved directly in the digestion of carbohydrates, not proteins or fats. Lactose intolerance occurs when there is a deficiency or decrease in lactase production, leading to the malabsorption of lactose in the small intestine.

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The Enzyme Lactase

Question 79

Multiple Choice

The enzyme lactase

A) is involved directly in the digestion of proteins.
B) is necessary for the breakdown of milk fats.
C) is embedded in the luminal plasma membranes of intestinal epithelial cells.
D) promotes the formation of and storage of bile by the gallbladder.
E) is overproduced and released by secretory cells in the small intestine in the condition known as lactose intolerance.

Correct Answer: