Final answer:
Statement D, that RNA has the same sugar-phosphate backbone as DNA, is false. DNA contains deoxyribose whereas RNA contains ribose, and RNA uses uracil in place of thymine. The sugar-phosphate backbone, base pairing, and helical structure are key differences between these nucleic acids. Option D is the correct answer.
Step-by-step explanation:
The student asked which statement about DNA is false. To determine this, we need to consider the structure and functions of DNA. The correct statements about DNA are that it is a double-stranded molecule (Statement A), adenine pairs with thymine (Statement B), and DNA replication occurs in the nucleus (Statement C). The false statement is D, that RNA has the same sugar-phosphate backbone as DNA, because DNA contains the sugar deoxyribose, whereas RNA contains the sugar ribose, and RNA uses uracil instead of thymine.
DNA is composed of nucleotides, which consist of a 5-carbon sugar called deoxyribose, a phosphate group, and a nitrogenous base. The DNA strands are antiparallel, meaning one strand runs in the 5' to 3' direction, while the complementary strand runs in the 3' to 5' direction. The structure of DNA is the famous double helix, where the strands are twisted around each other. Within the helix, adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G). The pairing is due to hydrogen bonding, with A and T forming two hydrogen bonds and C and G forming three hydrogen bonds. The phosphate and sugar create the backbone of the DNA strand, while the nitrogenous bases stick out like the 'rungs' of a ladder. RNA, while also a nucleic acid, is primarily single-stranded and has a different sugar (ribose) in its backbone, which distinguishes it from DNA.
Therefore, the correct answer is D: RNA has the same sugar-phosphate backbone as DNA, which is incorrect.