DNA forms a ______.

DNA forms a ______.

• A. Double helix
• B. Single helix
• C. Triple helix
• D. Random coil

Answer: (A)

DNA forms a double helix. In cells, DNA consists of two long strands of nucleotides that pair with each other and twist into a right-handed spiral. The two strands run antiparallel, with the sugar-phosphate backbones on the outside and the base pairs (A with T, G with C) forming the rungs inside. This arrangement, held together by hydrogen bonds between the bases, enables accurate replication and compact storage of genetic information. The other descriptions don’t fit DNA’s usual form: a single strand would be a single helix, three strands would be a triple helix, and a random coil lacks the orderly, helical structure.

DNA forms a double helix. In cells, DNA consists of two long strands of nucleotides that pair with each other and twist into a right-handed spiral. The two strands run antiparallel, with the sugar-phosphate backbones on the outside and the base pairs (A with T, G with C) forming the rungs inside. This arrangement, held together by hydrogen bonds between the bases, enables accurate replication and compact storage of genetic information. The other descriptions don’t fit DNA’s usual form: a single strand would be a single helix, three strands would be a triple helix, and a random coil lacks the orderly, helical structure.