Purines

Definition

Purines are a type of nitrogenous base found in nucleic acids, characterized by a two-ring structure. The most common purines in DNA and RNA are adenine (A) and guanine (G).

5 Must Know Facts For Your Next Test

1. Purines have a double-ring structure composed of carbon and nitrogen atoms.
2. Adenine pairs with thymine in DNA and with uracil in RNA through hydrogen bonds.
3. Guanine pairs with cytosine in both DNA and RNA through hydrogen bonds.
4. Purines are larger molecules compared to pyrimidines, which have a single-ring structure.
5. Purines play crucial roles in energy transfer, signal transduction, and as building blocks for nucleic acids.

Review Questions

• What are the two purines commonly found in DNA and RNA?
• How do purines differ structurally from pyrimidines?
• Why are purines important for the function of nucleic acids?

Related terms

Pyrimidines: Pyrimidines are nitrogenous bases with a single-ring structure, including cytosine, thymine (in DNA), and uracil (in RNA).

Nucleotide: A nucleotide is the basic building block of nucleic acids, consisting of a sugar, phosphate group, and nitrogenous base.

Hydrogen Bonding: Hydrogen bonding refers to the type of weak chemical bond that forms between complementary nitrogenous bases in DNA and RNA.