Identify each of the following bases as a pyrimidine or a purine:
a. cytosine

Verified step by step guidance

1. Understand the difference between pyrimidines and purines: Pyrimidines are single-ring nitrogenous bases, while purines are double-ring nitrogenous bases.
2. Recall the common pyrimidines: cytosine, thymine, and uracil. These are characterized by their single-ring structure.
3. Recall the common purines: adenine and guanine. These are characterized by their double-ring structure.
4. Examine the given base, cytosine, and identify its structure. Cytosine is a single-ring nitrogenous base.
5. Based on the structure of cytosine, classify it as a pyrimidine because it has a single-ring structure.

Key Concepts

Pyrimidines and Purines

Pyrimidines and purines are the two categories of nitrogenous bases found in nucleic acids. Pyrimidines, which include cytosine, thymine, and uracil, have a single six-membered ring structure. In contrast, purines, such as adenine and guanine, consist of a fused double-ring structure. Understanding the structural differences between these bases is essential for classifying them correctly.

Cytosine

Cytosine is one of the four primary nitrogenous bases in DNA and RNA. It is classified as a pyrimidine due to its single-ring structure. Cytosine pairs with guanine in DNA and RNA, playing a crucial role in the genetic code and the stability of nucleic acid structures. Recognizing cytosine's classification helps in understanding its function in genetic information.

Base Pairing

Base pairing refers to the specific hydrogen bonding between nitrogenous bases in DNA and RNA, which is fundamental for the structure of nucleic acids. In DNA, adenine pairs with thymine, and cytosine pairs with guanine. This complementary pairing is vital for DNA replication and transcription processes. Understanding base pairing is crucial for grasping how genetic information is stored and transmitted.