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Correct Answer: cellulose
cellulose is the correct answer to the question about which carbohydrate is a simple polymer of glucose that cannot be digested by the human digestive tract. unlike other carbohydrates that may serve as energy sources or storage forms of energy, cellulose has a unique role in the plant world.
cellulose is a complex carbohydrate or polysaccharide consisting of hundreds to thousands of glucose units linked together. these glucose molecules are bonded in a beta configuration, which results in a straight, rigid structure. the linear chains of glucose units are packed closely together to form strong fibers that provide structural support to plant cell walls. this configuration and bonding make cellulose highly stable and resistant to breakdown.
in the human digestive system, the enzymes necessary to break down beta linkages between the glucose molecules in cellulose are absent. specifically, humans lack the enzyme cellulase, which is required to cleave these bonds. as a result, cellulose passes through the human digestive tract undigested, acting instead as a source of dietary fiber. this fiber aids in digestion by helping to keep the digestive system active and by regulating the use of sugars, keeping hunger and blood sugar in check.
sources of cellulose in the diet include plant foods that are rich in fiber, such as bran, whole grains, and vegetables. while cellulose does not provide caloric energy to humans, its role in promoting digestive health and regularity is critical. it helps to increase stool bulk and is commonly recommended to aid in the treatment and prevention of constipation, hemorrhoids, and diverticulosis.
in summary, cellulose is a vital part of the human diet, not as a source of nutrients but as an essential component that aids in maintaining overall digestive health. its inability to be digested by humans underscores its role as a dietary fiber rather than a direct source of energy.
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