DNA and RNA are both nucleic acids, composed of repeating units called nucleotides. Each nucleotide consists of a sugar molecule (deoxyribose in DNA and ribose in RNA), a phosphate group, and a nitrogenous base.
In DNA, the sugar molecules are connected to each other by phosphodiester bonds. These bonds form between the phosphate group of one nucleotide and the hydroxyl (OH) group of the sugar molecule of the adjacent nucleotide. This linkage creates a sugar-phosphate backbone, which provides stability to the DNA molecule.
On the other hand, hydrogen bonds are responsible for holding the nitrogenous bases in DNA and RNA together. In DNA, there are four different bases: adenine (A), thymine (T), cytosine (C), and guanine (G). The hydrogen bonds form between complementary base pairs: A pairs with T (forming two hydrogen bonds) and C pairs with G (forming three hydrogen bonds). These hydrogen bonds are relatively weak, allowing the two strands of DNA to separate during replication and transcription processes.
In RNA, the basic structure is similar to DNA, but it contains the base uracil (U) instead of thymine (T) and the sugar ribose instead of deoxyribose. Like DNA, RNA molecules are also held together by phosphodiester bonds between the sugar molecules. However, RNA is typically single-stranded, and the hydrogen bonding occurs within the molecule itself, forming secondary structures such as hairpins and loops.
The difference in the type of bonds between DNA and RNA is primarily due to their respective functions. DNA carries genetic information and needs to remain stable, while RNA is involved in various biological processes, including protein synthesis, and requires more flexibility and structural versatility.
why the DNA molecules held toghether by hydrogen bond but RNA are by phosphodister bond
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