During sexual reproduction, sperm meet with an egg
to form a zygote. The sperm contains one strand of
DNA from the male, while the egg contains one
strand of DNA from the female. As a result, each
zygote contains two strands of DNA, one from the
mother and one from the father. Adult animals,
including humans, have two strands of DNA in all
of their body cells, and one strand of DNA in
their sperm or egg cells.
produce DNA for reproduction, this DNA is "housed"
within a sperm if the organism is male or an egg
if the organism is female. In humans, males
continually create new sperm throughout their
lives, so they are able to "grow it back" after
sexual reproduction. In contrast, human females
are born with a finite number of eggs (usually
about 2 million) which are located in the ovaries.
When a female is reproductively mature, the
ovaries release one of these eggs each month. The
egg travels towards the uterus and will become ane
mbryo if it is fertilized by sperm.
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