Question

Which one of the following statements about DNA is incorrect?

A. DNA has a diameter of approximately 2 nanometers.
B. The strands in DNA wrap around each other in a helix in B. an antiparallel manner
C. There are 10 base pairs per turn in a helical DNA molecule.
D. DNA typically exists in cells as a double helix.
E. All of the statements about DNA are correct.

Answer 1

Statement C is incorrect; there are 10.5 base pairs per turn in the helical DNA molecule, while others, including the 2 nm diameter and antiparallel strands, are correct.

Step-by-step explanation:

Among the given statements about DNA, the incorrect one is: C. There are 10 base pairs per turn in a helical DNA molecule.

In actuality, current models indicate there are approximately 10.5 base pairs per turn in the helical structure of DNA, not 10. The distance between each turn of the helix is 3.6 nm, contrary to the formerly accepted 3.4 nm.

The rest of the statements are accurate; the DNA double helix does have a diameter of approximately 2 nanometers, the strands are antiparallel, and DNA primarily exists in cells as a double helix.

Essential components of DNA's structure include a sugar and phosphate backbone and complementary pairing of nitrogenous bases where adenine pairs with thymine and cytosine pairs with guanine.