Molecular BiologyChapter 3 Nucleic Acid1 Physical and chemical structure of DNA● Double-stranded helix● Major groove and minor groove● Base pairing● The two strands are antiparallel● G+C content pe

in the single-stranded state. The melting temperature is affected by a variety of factors, including the length and sequence of the DNA, the concentration of salt in the solution, and the presence of other molecules that can bind to the DNA.5. RNA structureRNA (ribonucleic acid) is a single-stranded molecule that is similar in structure to DNA. The primary differences between RNA and DNA are that RNA contains the sugar ribose (rather than deoxyribose) and the base uracil (rather than thymine). RNA also tends to be much shorter than DNA, and can fold up into complex three-dimensional structures. There are three main types of RNA: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA)