Which of the following nitrogenous bases is NOT found in DNA?

Uracil is the nitrogenous base not found in DNA. Instead, it is a component of RNA. In DNA, the nitrogenous bases include adenine, thymine, cytosine, and guanine. Each of these plays a crucial role in the encoding of genetic information.

Thymine pairs with adenine in DNA, while cytosine pairs with guanine. Uracil serves a similar role in RNA, replacing thymine and pairing with adenine; however, because DNA and RNA have different structures and functions in cellular biology, uracil is specifically absent in DNA. This distinction is fundamental in genetics, especially when studying the processes of transcription and translation, where the presence of uracil marks a shift from DNA to RNA. Understanding this difference is essential for any veterinary technician or professional in the field of biology.