RNA Features Analysis

The question asks to identify which option is NOT a characteristic feature of Ribonucleic Acid (RNA).

Analyzing RNA Characteristics

• 1. Ribose in backbone: RNA contains ribose sugar in its phosphodiester backbone, distinguishing it from DNA, which has deoxyribose. This is a feature of RNA.
• 2. Principally single stranded: Unlike the typical double-stranded structure of DNA, RNA molecules are predominantly single-stranded. They can fold upon themselves to form complex secondary structures. This is a feature of RNA.
• 3. Uracil: RNA utilizes the nitrogenous base Uracil (U) in place of Thymine (T), which is found in DNA. Uracil pairs with Adenine (A). This is a feature of RNA.
• 4. Presence of major and minor grooves: Major and minor grooves are characteristic structural features that arise from the helical twisting of the sugar-phosphate backbone in double-stranded molecules, primarily DNA. Since RNA is usually single-stranded and does not typically form such a regular, stable double helix, it lacks these distinct grooves. Therefore, this is NOT a feature of RNA.

Conclusion on RNA Features

Based on the analysis, the presence of major and minor grooves is a characteristic feature of DNA's double helix structure, not RNA's predominantly single-stranded nature.

The correct option is 4.