Cell Specialization Ch.37

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Cell SpecializationCh.37
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The first cells were not specialized

• Organisms were unicellular
• The cell performed all cell functions

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This cell has to get energy, get rid of its
waste, reproduce all by itself!
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Multicellular organisms have specialized cells

• Each cell has a specific job
• Cells have special shapes and structures that
  relate to function

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This neuron is specialized to do one job receive
send messages.
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Think of an analogy to compare and contrast
unspecialized and specialized cells.
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How do you get from one cell to a multi-cellular
animal?
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How do cells become specialized?What do you
think happens?
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An organism starts off as one cell. That cell
divides by mitosis during development.
See its already starting to look like something
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Specialized cells develop from unspecialized STEM
CELLS
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When a cell divides, the new cells dont get the
same stuff
Each cell gets different chemicals
cells can affect their neighbors
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When a cell becomes specialized, some genes are
turned on in that cell and others are turned off.
If all of the cells expressed all of the genes in
the DNA, the organism would grow up to be a blob.
Not specialized
Not specialized yet
Specialized!
The on genes make their proteins which give the
cell its special structures
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Questions?
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Your Turn - Write in Your Notebook

• How are unicellular organisms different from
  multi-cellular organisms?
• How do cells in multi-cellular organisms become
  specialized?
• What is the advantage of being multi-cellular?

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Cells are arranged to form multi-cellular
organisms

• Tissues made of cells working together
• Skin
• Connective
• Muscle
• Organs made of tissues working together
• Heart
• Lungs
• Stomach
• Organ systems made of organs working together
• Digestive system
• Endocrine system
• Circulatory system
• Organism made of organ systems working together
• Human

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For now, tell me how you think this structure is
related to its function
This is a cross-section of your intestines.
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What about this
This is the lining of your wind pipe (trachea)
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What about this? How does structure relate to
function?
These cells transport water through a plant
(remember xylem?)