Q.12 Given below are two statements : One is labelled as Assertion (A) and the other is
labelled as Reason (R) :
Assertion (A) : Cotton and linen textiles have long durability due to cellulose’s side-
by-side aggregates which form cables.
Reasons (R) : Durability of cellulose is due to a -(1—6) glycosidic bonds.
In the light of the above Statements, choose the most appropriate answer from the
options given below :
(1)Both (A) and (R) are correct and (R) is the correct explanation of (A)
(2)Both (A) and (R) are correct but (R) is NOT the correct explanation of (A)
(3)(A) is correct but (R) is not correct
(4)(A) is not correct but (R) is correct
Answer: (3) (A) is correct but (R) is not correct.
Cotton and linen derive their durability from cellulose’s structural organization into microfibrils that pack side-by-side, forming cable-like bundles for tensile strength. However, cellulose’s primary bonds are β-(1→4) glycosidic linkages, not α-(1→6), making (R) factually incorrect.
Option Analysis
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(1) Both (A) and (R) correct, (R) explains (A): Incorrect. While (A) holds, (R) misstates cellulose bonding and doesn’t explain fibril aggregation.
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(2) Both correct, but (R) not explanation: Incorrect. (R) is false due to wrong glycosidic bond type.
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(3) (A) correct, (R) incorrect: Correct. Cellulose microfibrils provide durability via hydrogen-bonded aggregates; bonds are β-(1→4), not α-(1→6).
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(4) (A) incorrect, (R) correct: Incorrect. (A) accurately describes cellulose structure; (R) wrongly attributes durability to α-(1→6) bonds found in glycogen, not cellulose.
Cellulose cotton linen durability glycosidic bonds is a key topic in plant biology and textile science for exams like GATE Life Sciences. This assertion-reason question tests structural chemistry of natural fibers.
Cellulose Structure in Textiles
Cotton (Gossypium) and linen (flax) fibers contain 65-90% cellulose, forming parallel microfibrils that aggregate side-by-side via hydrogen bonds into cable-like structures. This organization provides exceptional tensile strength—linen up to 1.5 GPa—and longevity, even after repeated washing.
Glycosidic Bonds Reality
Cellulose chains link via β-(1→4) glycosidic bonds between glucose units, creating linear, rigid polymers with high crystallinity (60-80%). α-(1→6) bonds appear in branched polysaccharides like glycogen, not cellulose; misattributing durability to them ignores fibril packing and hydrogen bonding.
Exam Strategy Insight
Such questions distinguish structure (microfibrils, H-bonds) from bonding chemistry. Option (3) fits: (A) valid via aggregation, (R) invalid due to bond error. Wet strength increases in cotton (20%) from swelling-enhanced H-bonds.
This clarifies why cellulose-based textiles excel in durability for apparel and industrial uses.
