All Organisms have a set of
instructions that determine their characteristics.
These instructions are called genes and contain the
instructions for life that are
passed from parents to offspring during reproduction.
The inherited instructions
that are passed from parent to offspring exist as a
DNA molecule which makes up our genes contains this
The DNA molecules must be accurately replicated
before being passed on. Asexually reproducing
organisms normally pass on this genetic code identically
between the parent and offspring, while the
offspring of sexual reproduction produce offspring that
resemble their parents, but exhibit some
variations from them.
Changes in DNA or mutations which occur in non
sex cells of a sexually reproducing organism
will not be passed on to their offspring. Mutations
which occur in sex cells or gametes will be
frequently be passed on to their offspring.
Once the coded
information contained in the DNA molecule is passed on,
it is used by a cell to make proteins. The proteins that
are made become cell parts and carry out most functions
of the cell. The subtle differences in DNA
between different human beings and different species
results in the production of different
proteins. This is a major reason why
we show individual differences.
recorded history, humans have used selective breeding
and other methods to produce organisms with desirable
traits. Our current understanding of genetics and
heredity allows for the manipulation of genes and the
development of new combinations of traits and new
varieties of organisms. This includes
various aspects of DNA technology, including
recombinant DNA technology. Scientists have also developed many ways of determining
the genetic makeup of
different organisms, including humans.
This page and the links at the left are designed to aid students in
reviewing the following topics which will appear on the New
York State Living Environment Regents Examination; DNA
structure, sexual and asexual heredity, protein synthesis, and
genetic engineering. In addition, students may test their knowledge of the material presented here by accessing multiple-choice questions from past Regents Exams.