Final answer:
The true statement about DNA structure is that the nucleic acid strands in a DNA molecule are oriented antiparallel to each other. This arrangement is essential for DNA replication and interactions (option d).
Step-by-step explanation:
Among the given statements about DNA structure, the true one is 'd. The nucleic acid strands in a DNA molecule are oriented antiparallel to each other, meaning they run in opposite directions.' In the DNA double helix, the two strands are indeed oriented in opposite directions, with one strand running from the 5' to 3' direction and the other from 3' to 5'. This antiparallel orientation is crucial for the replication of DNA and for various nucleic acid interactions.
Each nucleotide in the DNA structure is connected to the next via a phosphodiester bond, which is formed between the 5' phosphate group of one nucleotide and the 3' hydroxyl group of the sugar in the next nucleotide. Contrary to choice 'b,' the pentose sugar in DNA is deoxyribose, not ribose, which is found in RNA. Additionally, Z-DNA is a less common form than the B-form DNA which is predominantly found in living cells, making choice 'c' incorrect. Lastly, adenine pairs with thymine via two hydrogen bonds and cytosine pairs with guanine via three hydrogen bonds, not the other way around as mentioned in choices 'a' and 'b'.
Hence, the answer is option d.