What is the difference between DNA and a genome?
Great question! Humans, and all of the members of our beloved pet family, are made up of millions of living cells that include the complete set of genetic instructions that are needed for our growth and development. This complete set of instructions is called the genome, and it includes our chromosomes, genes, and DNA.
A popular analogy is that the genome is like a recipe book for the body. The purpose of this recipe book is to hold the complete set of recipes (genetic instructions) that a living organism needs throughout life. We can think of DNA as the words, genes as the pages that hold these words, and chromosomes as the chapters that hold pages in this recipe book. So within a recipe book, there will be chapters (chromosomes) on side dishes, pages (genes) in those chapters that may be about rice sides or vegetable sides, and each dish will be accompanied by its own set of specific instructions (DNA) for how it is made.
Deoxyribonucleic Acid (DNA) is a complex organic molecule that contains the genetic instructions for making proteins that carry out specific functions in the body. This molecule is made up of two strands (sugar-phosphate backbones), winding around each other, that form the well-recognized “double helix” structure. Holding these strands together are the chemical building blocks of DNA called bases. There are four bases in total: adenine (A), which pairs with thymine (T), and cytosine (C), which pairs with guanine (G). Together, the sugar molecules, phosphate groups, and nitrogen-containing bases form nucleotides, and DNA consists of long chains of repeating nucleotides.