Which of the following statements about starch and cellulose is TRUE?

Question

BlackTom AI · Accepted Answer

Question: Which of the following statements about starch and cellulose is TRUE?

Option 1: 'animals can store glucose as starch and cellulose' This is incorrect because animals store glucose as glycogen, not starch. Starch is the storage polysaccharide used by plants, while cellulose is a structural polysaccharide in plant cell walls. Animals do not have the enzymes to hydrolyze cellulose for energy in humans, though some herbivores can digest cellulose with gut microbes.

Option 2: 'both are dietary fibres' This is not accurate. Dietary fiber typically refers to non-digestible carbohydrate components of plant foods. While cellulose is indeed a dietary fiber for many people, starch is digestible and serves as a major energy source, so labeling both as dietary fibres is misleading.

Option 3: 'starch is a polysaccharide, but cellulose is not' This is false. Both starch and cellulose are polysaccharides composed of glucose units. Starch is mainly α-1,4 and branched α-1,6 linkages (amylose and amylopectin), whereas cellulose consists of β-1,4 linkages, yielding a rigid, fibrous structure that humans cannot digest without specific enzymes.

Option 4: 'only starch is an energy molecule for humans' This aligns with physiological reality. Starch is digestible by humans to glucose, providing a major energy source. In contrast, cellulose resists digestion due to its β-1,4 glycosidic bonds and serves primarily as dietary fiber, aiding digestion but not providing usable energy for humans.

Which of the following statements about starch and cellulose is TRUE?单项选择题

类似问题

Most starches found in food contain ____ in differing proportions

This is glycogen. Look at those branches! What are the subunits (monomers / smallest units) of this polysaccharide?

This polymer that contains long strings of glucose. What is it?

Glycogen is a polymer of ________ molecules.

Starch and cellulose are alike in that both are:

Starch and cellulose ________.

Glycogen, starch, and fiber are ALL polysaccharides.

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