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Which of the following statements is/are INCORRECT? (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 of a DNA molecule are identical. (D) Glucose and fructose can be distinguished using Br2/H2O.

1. (A) alpha-D-glucopyranose has hemiacetal structure and is a reducing sugar.
2. (B) alpha-D-glucopyranose and beta-D-glucopyranose are anomers.
3. (C) The two helical strands in the DNA double helix are identical.
4. (D) Glucose and fructose can be distinguished using Br2/H2O.

Correct answer: (C) The two helical strands in the DNA double helix are identical.

Solution

The two strands of DNA are antiparallel and complementary to each other — one strand's base sequence is the complement of the other — so they are NOT identical. Statement C is the incorrect one. Statements A, B, and D are all factually correct.

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