Download 08 - WS Cell Specialization (answers)

1.3 Specialized Plant and Animal Cells
Regeneration process whereby a body part is replaced or re-grown
i.e. Salamander
Salamanders can re-grow limbs, and tails, but even eyes and parts of its heart. The process of
mitosis is responsible for regenerating the cells that will eventually specialize and create a
newly formed limb.
It is not very common in humans, but we may regenerate some parts like
fingertips
liver
We are uncertain why some organisms like salamanders can regenerate limbs when we can’t
even though our cells contain the same DNA
THE PROCESS OF CELL SPECIALIZATION
In many instances like wars, different people do different jobs. Some cook the food,
some are on the front lines, some are flying airplanes, and others fix the wounded. Each
individual become good at one thing or specializes in one aspect out of many. Even doctors
specialize what medicine they will study. Will they focus on the heart and be a heart surgeon or
look at the eye and become an optometrist. Even many video games allow you to specialize
(scout, medic, sniper etc).
Just like people our cells specialize. Some become heart cells to pump blood around the body,
some fight infection (white blood cells), and others become bone cells to hold us up. Cells
develop in different ways to perform particular functions in a process called cell specialization.
STEM CELLS
Every cell in your body originally came from a small group of stem cells. A stem cell is an
unspecialized cell. Stem cells can:
1. Form specialized cells when there are good environmental conditions
Or
2. Remain unspecialized and actively dividing for long periods of time.
Stems cells are the focus of a lot of time, money and research since they are being researched
and studies to help regenerate tissues and cure diseases. Since stem cells have the ability to
become any type of cell there are many applications (i.e. creating nerve cells to repair a broken
spinal cord to cure paralysis)
EMBRYONIC AND ADULT STEM CELLS
There are 2 types of stem cells
1. Embryonic stem cells which are found in embryos and are able to undergo
differentiation
Differentiation  the process by which a stem cell specializes (different look & job)
2. Adult stem cells  limited in the cells they can create
As an organism grows old, stem cells become specialized. In adults there are therefore only a
few examples of stem cells. Most adult stem cells are used by the body to replace damaged
tissue. (i.e. skin cells)
Most embryonic stem cells are created in a lab but some are taken from the umbilical cord or
placenta. But to collect large amounts of stem cells, it is necessary to destroy the embryo
Stem Cells in Plants
Stem cells are found in plants and are called meristematic.
They are found in the growing tips of roots. They are active throughout the life of a plant,
which means they continually produce new cells or various types.
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