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Which of the following statements is/are correct? (A) alpha-D-Glucopyranose has a hemiacetal structure and is a reducing sugar. (B) alpha-D-Glucopyranose and beta-D-Glucopyranose are anomers. (C) The two strands in a DNA molecule are exactly similar. (D) Glucose and Fructose can be differentiated by using Br2/H2O.

1. (A)
2. (B)
3. (C)
4. (D)

Correct answer: (A)

Solution

(A) is correct: the ring form of glucose is a hemiacetal at C1, and the free anomeric OH makes it a reducing sugar. (B) is also correct (alpha/beta differ at C1 = anomers). (C) is false — DNA strands are antiparallel and complementary. (D) is correct — Br2/H2O oxidises glucose (aldose) but not fructose (ketose).

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