Cell Specialization

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Cell Specialization
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• Unicellular Organism consists of only one cell
• - that one cell carries out all functions
  required to maintain the life of the organism
• Multicellular Organism consists of more than
  one cell
• Cells are specialized to perform certain
  functions (cell specialization/differentiation)

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Examples of Cell Specialization

• Neuron (nerve cell)
• - sends info from one part of the body to
  another
• - very long and thin

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Examples of Cell Specialization

• Red Blood Cells
• - carry oxygen throughout body
• - flattened disks so that they can easily flow
  through blood vessels

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Examples of Cell Specialization

• Sperm Cell
• - fertilizes egg
• - strong tail for quick swimming, distinct head
  for entering egg cell

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• Cell differentiation is a result of different
  gene expression.

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• Most cells in your body have the same DNA
• Cells use only the DNA that they need the rest
  is inactive
• For example, skin cells use the DNA that codes
  for melanin (a skin pigment that protects from UV
  light)
• Heart cells do not need melanin, so it is turned
  off in heart cells

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Stem Cell Research

• stem cells cells of humans that can develop
  into different cell types

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• 2 kinds embryonic and adult
• some researchers believe that they can be a
  source of replacement cells to treat disorders
  (ex. Parkinsons disease and burn injuries)

Embryonic stem cells
Adult stem cells
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Cell Communication

• Cells communicate with one another by secreting
  and receiving chemicals
• - Chemicals released by one cell can influence
  the activity of another cell

http//learn.genetics.utah.edu/content/begin/cells
/cellcom/
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Example of Cell Communication

• - Sensory cells to nerve cells to muscle cells

http//bcs.whfreeman.com/thelifewire/content/chp46
/46020.html
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Cell Communication (cont.)

• Hormone communication chemicals that travel
  through the blood (ex. insulin, estrogen)
• - Secreted by endocrine glands

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• Acts much slower than nerve impulses but effects
  last much longer
• Only influence the action of target cells that
  have specific receptors

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Two Hormone Mechanisms

• 1. Negative Feedback the end product stops
  the production of the hormone

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Negative Feedback
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• Positive Feedback the last step triggers more
  release of the initial hormone or other hormones
• - triggers a series of events