The variable component of nucleotides; in DNA, adenine, guanine, thymine, and cytosine; in RNA, uracil replaces thymine.

The variable component of nucleotides; in DNA, adenine, guanine, thymine, and cytosine; in RNA, uracil replaces thymine.

• A. Nucleotide
• B. Base
• C. Sugar
• D. Amino Acid

Answer: (B)

The part that varies among nucleotides is the nitrogenous base. Each nucleotide is built from a sugar (deoxyribose in DNA or ribose in RNA), a phosphate group, and one base. The sugar and phosphate form the backbone of the strand, while the base differs from nucleotide to nucleotide, giving each nucleotide its identity. In DNA you have adenine, guanine, cytosine, and thymine; in RNA thymine is replaced by uracil. That base variation is what carries the genetic information through specific base-pairing (A with T or U, and G with C).

The part that varies among nucleotides is the nitrogenous base. Each nucleotide is built from a sugar (deoxyribose in DNA or ribose in RNA), a phosphate group, and one base. The sugar and phosphate form the backbone of the strand, while the base differs from nucleotide to nucleotide, giving each nucleotide its identity. In DNA you have adenine, guanine, cytosine, and thymine; in RNA thymine is replaced by uracil. That base variation is what carries the genetic information through specific base-pairing (A with T or U, and G with C).