What happens to nutrient macromolecules in an animal's digestive tract?
A) They are absorbed whole and are then broken down into monomers within cells that ultimately use them.
B) Proteins and nucleic acids are digested into monomers before absorption; energy-storage macromolecules (starch and fat) are absorbed whole.
C) The digestive breakdown of macromolecules determines the monomers that are immediately needed and therefore produced.
D) Nutrient macromolecules are digested into monomers before absorption.

Question

Quizplus · Accepted Answer

Nutrient macromolecules, such as carbohydrates, proteins, and lipids, are broken down into their monomers (glucose, amino acids, and fatty acids/glycerol, respectively) through enzymatic hydrolysis in the digestive tract of animals. These monomers are then absorbed through the walls of the small intestine and transported to various cells in the body where they are used for energy, growth, and repair. Therefore, option D is the best choice.

What Happens to Nutrient Macromolecules in an Animal's Digestive Tract