What Is DNA?

DNA (deoxyribonucleic acid) is found in almost all the cells of our body. Within those cells DNA is mostly housed in the nucleus, while a much smaller amount of DNA can be found in mitochondria. DNA contains the instructions (blueprints) for putting specific amino acids together to make proteins. You see, the human body contains thousands of different proteins, all of which our cells have to build using amino acids as the building blocks. Without the DNA’s instructions, our cells would not know how to perform such a task.
 

DNA is long and strand-like and organized into large structures called chromosomes. Normally we have twenty-three pairs of chromosomes in our nuclei. If we were to take a chromosome and find the end points of the DNA, we could theoretically straighten it out like thread from a spool. If we did so we would find thousands of small stretches called genes on the DNA. We have thousands of genes, which contain the actual
instructions for building specific proteins.
 

Human DNA contains around twenty-five thousand genes, which code for proteins. Each person has a unique gene profile.
 

To oversimplify one of the most amazing events in nature, when a cell wants to make a specific protein, it makes a copy of its DNA gene in the form of RNA (ribonucleic acid). You see, DNA and RNA are virtually
the same thing. However, one of the most important differences is that the RNA can leave the nucleus and travel to where proteins are made in cells—the ribosomes (see Figure 2.1). At this point both the blueprint instructions (RNA) and the amino acids are available and it’s the job of the ribosomes to link (bond) amino acids together in the correct sequence.