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Cell Differentiation
Mrs. Harlin
1.1.3

Explain how instructions in DNA lead to
cell differentiation and result in cells
specialized to perform specific functions in
multicellular organisms.
Specialized Cells

Multicellular organisms begin as
undifferentiated masses of cells and
variation in DNA expression and gene
activity determines the differentiation of
cells and ultimately their specialization.
Differentiation
Only specific parts of the DNA are
activated; the parts of the DNA that are
activated determine the function and
specialized structure of a cell.
 Because all cells contain the same DNA, all
cells initially have the potential to become
any type of cell; however; once a cell
differentiates, the process cannot be
reversed.

DNA
Nearly all the cells in an organism contain
the same chromosomes and DNA.
 Different parts of the genetic instructions
are used in different types of cells,
influenced by the cell’s environment and
past history.

Hormones

Hormones are
chemical signals
that are released
by cells that
influence the
development and
activity of other
cells.
Stem Cells

Unspecialized cells that
continually reproduce
themselves and have,
under appropriate
conditions, the ability to
differentiate into one or
more types of specialized
cells.
Types of Stem Cells
Embryonic stem cells
 Adult stem cells- found in bone marrow


Research has demonstrated both types of
stem cells can be differentiated into
specialized cells.
Specialized cells in Animals
Nerve cellseukaryotic, but
have dendrites and
axons for
electrochemical
communication in
the body.
 They are never
replaced when
they die.

Specialized cells in Animals

Muscle cellseukaryotic; used for
movement.
– Skeletal muscles
contain many nuclei
and are striatedvoluntary movement.
– Smooth muscles only
have 1 nucleusinvoluntary movement
Specialized cells in Animals

Blood cells
– Red blood cells- the hemoglobin protein transports
oxygen and carbon dioxide (influenced by
temperature and pH)
 Do not divide
 No mitochondria or nucleus
– Plasma- transports materials
 Insulin regulates glucose levels
 Lipids, amino acids, and other ions also transported from
digestive system.
– White blood cells- protects the body from infection
 Has a nucleus
m
Specialized cells in Animals

Gametes- Sperm and
egg cell
– Used in sexual
reproduction
– Only contain half the
DNA as the rest of the
cells in an organisms.
– Haploid number for
humans= 23
chromosomes
Specialized Cells in Plants
Xylem- transports water from roots
 Phloem- transports water and sugars

References
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http://www.sciencedaily.com/releases/2007/12/0
71220123837.htm
heal-thyself.us
http://faculty.washington.edu/chudler/cells.html
http://www.kidsbiology.com/human_biology/mu
scles2.php
health-niche.com
http://www.mcatzone.com/glosslet.php?letter=g
ap-bio-patrick-steed.wikispaces.com