Page 57 - Demo 1

development. Together, mitosis and meiosis provide the cellular basis for
healthy growth and sexual reproducon.

SIGNIFICANCE OF MITOSIS

Mitosis is the process by which non-sex cells or somac cells divide to
make new cells. It always produces two cells that are genecally idencal to each
other and the original cell. Through mitosis, individuals are able to grow body
parts, to develop, to repair damaged ssues, to replace dead cells, and to
change at a cellular level as they mature.

Indirectly, mitosis is important for sexual reproducon. It allows the
sexually reproducing organism to grow and develop from a single cell into a
sexually mature individual. Soon aer ferlizaon, mitosis begins making copies of
the newly formed zygote. The first cell duplicates itself through mitosis, and
the two resulng cells will each be duplicated. This process will connue
exponenally throughout the organism's lifeme, allowing organisms to connue
to reproduce through the generaons.

SIGNIFICANCE OF MEIOSIS
One of the benefits of sexual reproducon is the diversity it produces
within a populaon. Meiosis is the process by which sexually reproducing
organisms make their sex cells, the sperm and egg cells. Every sex cell made
from meiosis has a unique combinaon of chromosomes such that no two
sperm or egg cells are genecally idencal. Similarly, every ferlizaon event
produces a new combinaon of traits. This is why siblings, though sharing DNA
with their parents and each other, are not idencal to one another.

Genec diversity occurs because certain physical characteriscs, like eye
color, are variable. This variability is the result of alternate DNA sequences that
code for the same physical characterisc. These sequences are commonly
referred to as alleles. The various alleles associated with a specific trait are
only slightly different from one another, and they are always found at the same
locaon (or locus) within an organism's DNA. For example, regardless of
whether a person has blue eyes, brown eyes, or green eyes, the alleles for eye
color are found in the same area of the same chromosome in all humans. The
unique combinaon of alleles that all sexually reproducing organisms receive
from their parents is the direct result of recombinaon during meiosis.

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