Download Cell Specialization

The first cells were not specialized
• Organisms were unicellular
Cell Specialization
• The cell performed all cell functions
Multicellular organisms have
specialized cells
• Each cell has a specific job
• Cells have special shapes and structures that
relate to function
This cell has to get its energy, get rid of its waste,
reproduce, make everything it needs to make, regulate
everything it needs to regulate, and do everything!
All by itself!
Think of an analogy to compare
and contrast unspecialized and
specialized cells.
This cell is specialized to do one job. This is a neuron – it
receives and sends messages. Notice the long thin
extensions – these help connect this cell to other cells so
that they can communicate with each other.
How do you get from one cell to
a multi-cellular animal?
An organism starts off as one cell. That cell divides by
mitosis during development. If all of the cells expressed all
of the genes in the DNA, the organism would grow up to be
a blob. But it doesn’t…
Fully developed Sea
Urchin
See… its already starting to look like something…
Specialized cells develop from
unspecialized STEM CELLS
When a cell divides, the new cells
don’t get the same stuff
Each cell gets
different chemicals
& cells can affect their neighbors
When a cell gets its job (becomes specialized), some
genes are turned on in that cell and others are turned off.
Not specialized
Your Turn - Write in Your
Notebook:
• How are unicellular organisms different
from multi-cellular organisms?
Not specialized yet…
• How do cells in multi-cellular organisms
become specialized?
Specialized!
• What is the advantage of being multicellular?
The “on” genes make their proteins which
give the cell its special structures
Cells are arranged to form multicellular organisms
For now, tell me how you think this
structure is related to its function:
• Tissues – made of cells working together
– Skin
– Connective
– Muscle
• Organs – made of tissues working together
– Heart
– Lungs
– Stomach
This is a crosssection of your
intestines.
• Organ systems – made of organs working together
– Digestive system
– Endocrine system
– Circulatory system
• Organism – made of organ systems working together
– Human
What about this:
This is the
lining of your
wind pipe
(trachea)
What about this? How does
structure relate to function?
These cells
transport
water through
a plant
(remember
xylem?)