What is the backbone sugar in ribonucleic acid (RNA)?

In ribonucleic acid (RNA), the backbone sugar is ribose. Ribose is a five-carbon sugar (pentose) that plays a crucial role in the structure of RNA molecules. In RNA, ribose connects to a phosphate group, forming the backbone of the nucleic acid strand. Each ribose molecule is attached to a nitrogenous base, allowing RNA to carry genetic information and participate in protein synthesis.

The other sugars mentioned do not pertain to RNA's structure: glucose is a six-carbon sugar commonly used for energy, deoxyribose is the sugar found in DNA (where one oxygen atom is missing compared to ribose), and fructose is a fruit sugar that is also not involved in the structure of nucleic acids. This specificity and the unique structure of ribose are essential for the proper functioning and stability of RNA.