GETTING STARTED
Life on Earth began almost four
billion years ago with the formation
of the first cells. Since then, cells
have multiplied and changed to
form the huge number of different
organisms we see today. Over the
past several hundred years, we
have learned so much about the
structure and function of cells that
we are able to put cells to work in
beneficial ways and fix or prevent
many of the problems that affect
cells. In Canada, scientists have
modified cells so that they produce
chemicals called antibodies that
fight diseases such as cancer,
leprosy, and tetanus (lockjaw).
Other Canadian scientists have
fused white blood cells (that
produce antibodies) to cancer cells
(that multiply rapidly) to create
new, mixed cells. These cells
produce larger quantities of
beneficial antibodies than the
white blood cells would produce on
their own.
When a person is burned, the skin
in the affected area is destroyed.
In the past, surgeons would
replace burned skin with pieces of
skin, called skin grafts, taken from
unburned parts of the body. The
grafts grow in the new location,
but the area that the skin was
taken from must also grow new
skin cells. This was a painful
process that can now be avoided
with the use of artificial skin.
Biologists grow artificial skin from
skin cells incubated in petri dishes
outside of the body. As a result,
new skin grown in the laboratory
can now be used to replace burned
skin.
Scientists have also been able to
change one type of cell into
another. For example, skin cells
have been forced to change into
bone cells and, in more recent
advances, fat cells have been
changed into nerve cells. These
are important advances in medical
technology as they could provide a
treatment for diseases such as
osteoporosis and Parkinson's
disease.
Modern cell research is conducted
in laboratories all over the world.
In addition to cell research, many
laboratories, called diagnostic
laboratories, conduct routine tests
on samples of cells, tissues, and
body fluids to determine the
presence of disease or the type of
disease a person or animal may
have. A common medical
laboratory procedure (called a
biopsy) involves looking for cancer
cells in a small sample of tissue
that medical doctors remove from
a patient's body. Other laboratories
conduct studies on cells that are
important in food and beverage
industries. In these facilities,
biologists, technicians, and
technologists work as a team to
discover more about how cells
work and how they affect food
processing.
REFLECT on your learning
1. How has the microscope
benefited the study of biology?
2. There are four major classes of
biological compounds:
carbohydrates, lipids, proteins, and
nucleic acids. Which class includes
compounds that cells use as a
ready source of energy? to store
energy? to store genetic
information?
3. What will happen to the size of a
cell that is placed in distilled
water? Why?
4. The chemical reactions of life
must occur at a relatively fast rate.
Most chemical reactions double in
speed with every 10ºC increase in
temperature.
(a) Why can’t living cells use large
amounts of heat to speed up
reactions?
(b) How do cells increase the
speed of chemical reactions
without using large amounts of
heat?