1. Thymine (T) is replaced by Uracil (U):

In DNA, the nitrogenous bases adenine (A), cytosine (C), guanine (G), and thymine (T) form base pairs. In RNA, uracil (U) replaces thymine, forming base pairs with adenine.

2. Ribose sugar instead of Deoxyribose:

The sugar-phosphate backbone of RNA is made up of ribose, which has a hydroxyl group (-OH) at the 2' carbon atom. In DNA, the backbone consists of deoxyribose, which lacks this hydroxyl group.

3. Single-stranded vs. Double-stranded:

RNA molecules are typically single-stranded, meaning they consist of a single chain of nucleotides. On the other hand, DNA molecules are double-stranded, consisting of two complementary strands that form a double helix structure.

4. Location:

RNA is primarily located in the cytoplasm and is involved in various cellular processes like protein synthesis, gene regulation, and signaling. DNA, on the other hand, is primarily located in the cell's nucleus and serves as the genetic blueprint for the cell.

Summary:

The nitrogenous bases in RNA differ from those in DNA primarily due to the replacement of thymine (T) with uracil (U). RNA utilizes uracil instead of thymine in its base-pairing with adenine. Additionally, RNA molecules are typically single-stranded and primarily function within the cytoplasm, while DNA is double-stranded and primarily located in the cell's nucleus.