RNA does not usually form a double-helix structure like DNA. DNA is known for its double-helix shape, which consists of two strands that twist around each other. In contrast, RNA typically exists as a single-stranded molecule. This single-stranded nature of RNA allows it to adopt various shapes and structures based on its sequence and interactions within the molecule.
One example of RNA's single-stranded structure is messenger RNA (mRNA), which carries genetic information from the DNA in the cell's nucleus to the ribosomes in the cytoplasm where proteins are synthesized. mRNA is transcribed from a DNA template and is usually a linear molecule without the characteristic double-helix structure of DNA.
Therefore, the statement that RNA usually forms a double-helix is false. RNA is primarily single-stranded, with the exception of certain RNA molecules that can form temporary secondary structures through base pairing or interactions with other molecules.
