Download A zygote is formed when a sperm cell combines with an egg cell

1. A zygote is formed when a sperm cell
combines with an egg cell.
2. Differentiation is when “plain” stem cells
turn genes “on” and “off” in order to
become specialized cells (e.g. neurons,
white blood cells, red blood cells).
3. A zygote divides to form 2 identical cells
that usually stick together.
10.Sperm is formed by meiosis in testes. It
then travels to the vas deferens and,
finally, the urethra where it is released.
11.One egg is released from the ovary
during ovulation; the other 3 polar
bodies degenerate (break down).
12.Nutrients and oxygen are taken from the
mother’s blood and pass through the
placenta and then the umbilical cord.
4. Early stages of mitosis are called
cleavage (e.g. zygote  2 cells  4 cells
 8 cells, etc.); all cells that are formed
look the same.
13.Spermatogenesis, oogenesis,
gametogenesis.
5. The fetus develops in the uterus.
14.Carbon dioxide is taken from the fetus’
blood and passes through the placenta
back to the mother who can excrete it.
6. Alcohol, drugs, tobacco, a poor diet,
exposure to toxic substances, and
certain diseases can adversely affect a
fetus.
7. One body cell produces an exact copy of
itself…unless there’s a mutation!
8. Side Note: The uncontrolled division of
body cells, which then spread
throughout the body, is called cancer.
9. A cell in a gonad (testis or ovary) turns
into a gamete with half the chromosome
number.
15.Gametes are formed.
16.The ovaries produce eggs through the
process of meiosis. The egg then travels
to the oviduct and then the uterus.
17.The male urethra allows for the passage
of sperm (reproductive system) or urine
(excretory system).
18.Homologous (1 from mom, 1 from dad)
chromosomes exchange pieces of
genetic info in a process called crossing
over; this is a source of genetic variation.
19.Fertilization takes place in the oviduct
a.k.a. Fallopian tube.