Which base is used in RNA but not in DNA?

Which base is used in RNA but not in DNA?

• A. Adenine
• B. Cytosine
• C. Guanine
• D. Uracil

Answer: (D)

Uracil is the base used in RNA but not in DNA. RNA carries adenine, uracil, cytosine, and guanine, while DNA carries adenine, thymine, cytosine, and guanine. The presence of uracil in RNA allows it to be synthesized quickly and used for short-term tasks, since RNA is typically temporary in the cell. Thymine in DNA provides extra stability through the methyl group and helps repair systems distinguish true genetic information from damage; if uracil appeared in DNA, deamination of cytosine could be mistaken for a normal base, complicating repair. So, the base unique to RNA is uracil, which pairs with adenine in RNA processes.

Uracil is the base used in RNA but not in DNA. RNA carries adenine, uracil, cytosine, and guanine, while DNA carries adenine, thymine, cytosine, and guanine. The presence of uracil in RNA allows it to be synthesized quickly and used for short-term tasks, since RNA is typically temporary in the cell. Thymine in DNA provides extra stability through the methyl group and helps repair systems distinguish true genetic information from damage; if uracil appeared in DNA, deamination of cytosine could be mistaken for a normal base, complicating repair. So, the base unique to RNA is uracil, which pairs with adenine in RNA processes.