True or False: Asymmetrical spacing of the DNA backbones generates major and minor grooves.

True or False: Asymmetrical spacing of the DNA backbones generates major and minor grooves.

• A. Not applicable
• B. False
• C. Both
• D. True

Answer: (D)

The spacing of the two sugar-phosphate backbones around the DNA double helix is not the same on all sides, so as the strands twist, two distinct spaces appear: a wide major groove and a narrow minor groove. This unequal spacing is what creates the two grooves, not a single uniform surface. The major groove is large enough to let proteins and other molecules “read” the exposed edges of the base pairs, facilitating sequence-specific interactions, while the minor groove presents a different, smaller surface with its own pattern of contacts. Because the asymmetrical arrangement of the backbones leads directly to these two grooves, the statement is true.

The spacing of the two sugar-phosphate backbones around the DNA double helix is not the same on all sides, so as the strands twist, two distinct spaces appear: a wide major groove and a narrow minor groove. This unequal spacing is what creates the two grooves, not a single uniform surface. The major groove is large enough to let proteins and other molecules “read” the exposed edges of the base pairs, facilitating sequence-specific interactions, while the minor groove presents a different, smaller surface with its own pattern of contacts. Because the asymmetrical arrangement of the backbones leads directly to these two grooves, the statement is true.