Which of the following is a key difference between DNA and RNA?

• A. DNA is single-stranded while RNA is double-stranded.
• B. DNA is found only in the cytoplasm while RNA is found only in the nucleus.
• C. RNA has a deoxyribose sugar while DNA has a ribose sugar.
• D. RNA contains uracil instead of thymine.

Answer: (D)

Verified step by step guidance

1. Understand the basic structure of nucleic acids: DNA and RNA are both nucleic acids composed of nucleotides, which include a sugar, a phosphate group, and a nitrogenous base.
2. Identify the sugars in DNA and RNA: DNA contains deoxyribose sugar, while RNA contains ribose sugar. This is a fundamental structural difference between the two.
3. Examine the nitrogenous bases: DNA uses adenine, thymine, cytosine, and guanine as its bases. RNA uses adenine, uracil, cytosine, and guanine. Note that uracil in RNA replaces thymine found in DNA.
4. Consider the strand structure: DNA is typically double-stranded, forming a double helix, whereas RNA is usually single-stranded, allowing it to fold into various shapes.
5. Locate where DNA and RNA are found in the cell: DNA is primarily located in the nucleus, while RNA can be found in both the nucleus and the cytoplasm, where it plays a role in protein synthesis.