in
eukaryote cells DNA is found in the nucleus of the cell, the form the
DNA (e.g. chromosomes vs. chromatin) is in depends on what stage of the
cell cycle you are talking about. In cells that have mitochondria, DNA
is found there as well. Mitochondrial DNA is distinct from nuclear DNA
and doesn't code for the same things. In prokaryotic cells DNA is found
in the cytoplasm. Don't forget that other entities may also contain DNA
such as viruses.
Although DNA is technically confined to the places outlined above, the
reality is cells are dying all the time and spilling their contents
including their DNA. As a result DNA is all over us and everything we
touch, and the same goes for other organisms.
Bacterial cells DON'T typically have a nucleus. They are called
prokaryotic because of that (prokaryotic means "before nucleus" where as
eukaryotic means "true nucleus"). Their DNA is typically in the
cytoplasm usually as a single circular shaped chromosome. The also
sometimes have smaller peices of circular DNA called plasmids that are
also in their cytoplasm which they can exchange with each other..
