What are the main differences between RNA and DNA?

The correct answer highlights the primary distinctions between RNA and DNA in molecular biology. RNA, or ribonucleic acid, is generally single-stranded, which allows it to participate in various roles in the cell, such as acting as a messenger (mRNA) and playing crucial roles in protein synthesis (tRNA and rRNA). This single-stranded nature enables RNA to fold into complex three-dimensional shapes necessary for its functions.

In contrast, DNA, or deoxyribonucleic acid, is typically double-stranded and forms a stable helical structure known as the double helix. Each strand is complementary to the other, which is key to its function in storing and transmitting genetic information.

Additionally, the bases found in RNA and DNA differ. RNA contains uracil instead of thymine, which is found in DNA. This substitution is significant for the molecular recognition and pairing of nucleotides during processes like transcription and translation in protein synthesis.

Understanding these differences is crucial in the study of molecular biology, genetics, and biochemistry, as they lay the foundation for how genetic information is stored, replicated, and expressed in living organisms.