Final answer:
In DNA, a codon is analogous to a "word" in a book. It comprises a group of three nitrogenous bases and corresponds to a single amino acid or a start and stop signal in protein synthesis.
Step-by-step explanation:
In the genetic code that comprises our DNA, the component analogous to a "word" in a book is the codon. A codon is a sequence of three nitrogenous bases in nucleic acids that constitutes a code word in the genetic code. Each codon corresponds to one amino acid, or it may signal the start or stop of protein synthesis. In the context of a DNA sequence, such as ATC/GTT/GAA/CTG/TAG/GAT/AAA, each set of three bases separated by slashes is a codon. Much like words in a language, codons are critical for translating genetic information to create proteins necessary for the body's functions.
The bases adenine (A), cytosine (C), guanine (G), and thymine (T) in DNA, and uracil (U) in RNA, are the "letters" that make up these genetic words or codons. The sequence of these bases in a gene provides the instructions for the correct sequence of amino acids in a protein, just as letters form words that convey meaning in a sentence. Since there are 64 possible codons but only 20 common amino acids, some amino acids are encoded by more than one codon, demonstrating the redundancy of the genetic code.