What are the four nitrogenous bases of DNA, and what is their importance?

The four nitrogenous bases of DNA are adenine (A), thymine (T), cytosine (C), and guanine (G). These bases are crucial because they form the genetic code that determines the characteristics of living organisms. Here's a brief explanation of their importance:

1. Base Pairing: Adenine pairs with thymine, and cytosine pairs with guanine. This complementary base pairing is essential for the structure of the DNA double helix and for accurate replication of DNA during cell division.

2. Genetic Code: The sequence of these bases along the DNA strand constitutes the genetic code, which is read in sets of three bases called codons. Each codon specifies a particular amino acid, the building blocks of proteins.

3. Genetic Variation: Variations in the sequence of these bases lead to genetic diversity, which is the basis for evolution and adaptation in living organisms.

4. Gene Expression: The order of these bases determines the sequence of amino acids in proteins, which in turn affects the function and regulation of genes within an organism.

In summary, the nitrogenous bases are fundamental to the storage and transmission of genetic information, influencing everything from cellular function to the traits of an organism.