What Is DNA?

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 . 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.