Final answer:
DNA molecules differ from RNA in that DNA is double-stranded, contains deoxyribose sugar, and uses thymine, while RNA is single-stranded, contains ribose, and uses uracil instead of thymine.
Step-by-step explanation:
Based on the structure, DNA and RNA molecules differ from each other in several ways. The correct answer to the student's question is option a. RNA contains the base uracil, whereas DNA does not contain uracil.
DNA is composed of two strands forming a double helix. It includes a phosphate group, a five-carbon sugar called deoxyribose, and four nitrogenous bases: adenine, cytosine, guanine, and thymine. In contrast, RNA is generally single-stranded and uses a different sugar in its nucleotides: ribose instead of deoxyribose. Instead of thymine, RNA features uracil as one of the nitrogenous bases, which pairs with adenine.
Both nucleic acids are essential for the storage and expression of genetic information. DNA contains the instructions needed for an organism's development and function, whereas RNA is crucial in various roles, including serving as a messenger between DNA and ribosomes to produce proteins