LAD DNA and ANA: The Central Dogra ol Biology 99 DNA replicmige in considered
semiconservative because half of the oreinal strand bs conserved and stays together.As yon can
see in the image abore, one original blue stand remains intact in each of the final nolecules. and a
dew yellow strand gets built and anached to it via basc pauring. Pracrice DNA replication below
by usine the base painng nole- DNA tequence: ATCCGTAAGGTCA Makching strand: The
image bekrw is nor in the comect order. Recond the nombers an the contet onder Mutations
Sometimes, mistakes happea, even during D.AA replication. A mutation is when the genelic
code changes. There are varioes ways this can happen isee image below, does not inclode all
possibie mutarions). Most mutations are noither bad nor beneficial, cither becawse they happen
in the junk DNA," do noc cause a change in armino acid, ar produce changes they can't really be
valueal as good or bad. Several matations are harmful, and a small few are beneficial (such as
oertain people being immuac io HIV because their cells lack the receptors for the virus). There
are many haman genetic diseaves, sach as sickle oell anemia, hemophitha, and many mwore.
About 3,000 genetic disorders have been identified so far.