A Level Biology Practice Exam

Which of the following statements best describes cellulose fibers?

1. They are soluble and easily digestible

2. They can coil and branch easily

3. They form strong and insoluble fibers

4. They are made from alpha glucose

The correct answer is: They form strong and insoluble fibers

Cellulose fibers are primarily composed of long chains of beta glucose units that are linked together by glycosidic bonds. This structure allows cellulose to form very strong and insoluble fibers, which are essential for providing structural support in plant cell walls. The strength of these fibers is due to the extensive hydrogen bonding that occurs between adjacent cellulose chains, leading to high tensile strength and rigidity. In contrast to the other options, which either describe properties that are not characteristic of cellulose (such as being soluble and digestible or made from alpha glucose), this option accurately reflects the physical and chemical nature of cellulose fibers. Their insolubility and strength are critical for maintaining the integrity and structure of plant cells and tissues.