7.4 Homeostasis and Cells

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7.4 Homeostasis and Cells

• Cells have the same basic composition, and the
  same kinds of organelles, but not all living
  things are the same
• Cells are specialized and associate with other
  cells in special ways

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How do unicellular organisms maintain homeostasis?

• Homeostasis relatively constant internal
  physical and chemical conditions
• What workbook question deals with the definition
  of homeostasis?
• 1
• Whats the answer to 6?

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6. Unicellular Organisms

• Single-celled organisms
• Maintain homeostasis
• Grow
• Respond to the environment
• Transform energy
• Reproduce

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7. Why is that important to single-celled
organisms?

• They consist of only ONE cell, so homeostasis is
  vital to their life. If they lose the ability to
  keep their internal conditions stable, they face
  immediate death

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What are the types of unicellular organisms?

• Look at 2 - 5

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Types of Unicellular Organisms

• Eukaryotes
• Protozoa (picture on p214),
• Algae have chloroplasts, found in water
• Yeast (a unicellular fungi) used in baking
  bread and other foods
• Prokaryotes
• Bacteria highly adaptive and can live almost
  anywhere
• Both prokaryotes and eukaryotes, though
  unicellular, ARE alive and maintain homeostasis

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8. How are cells of multicellular organisms like
a baseball team?
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Multi-cellular Organisms

• Cells have a certain job in the body and are
  specialized for their task
• Members of a baseball team have different jobs
  coach, catcher, pitcher, fielders, trainers
• Need to communicate effectively
• So do cells!

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9. How does a multicellular organism maintain
homeostasis?

• Specialized cells from various parts of the body
  work together and communicate effectively
• Cooperate with each other for survival of the
  organism

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Some specialized cells -

• Fig 7-22 p.215 Human trachea epithelial cells -
  have cilia to catch debris when you breathe in
  air
• Fig 7-23 Pollen grains from pine tree
• Tiny, lightweight, protective covering
• Float in the wind until they land on seed cone

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10. What are the levels of organization that
make up a multicellular organism?

• Most basic level is

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Levels of Organization

• Cells make
• Tissues, which make
• Organs, which make
• Organ systems, which makes
• Organisms
• Where would youput organism?Another organ?

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STOP HERE

• The following slides are from LAST YEAR. We
  arent doing this part!

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Cellular Communication

• Cells are specialized, but interdependent
• Cells MUST communicate effectively
• Some cells form a connection to another cell,
  called cellular junctions

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• Signals pass through junctions, but only if they
  have the right receptor specific protein that
  has specific shape that molds to a specific
  molecular messenger
• Ex junctions in the heart electrical signals
  pass through junctions to make heart contract and
  pump blood

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Pop Quiz!

• 1. What is homeostasis?

The relatively constant internal physical and
chemical conditions that occurs in both
unicellular and multicellular organisms
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• 2. What do unicellular organisms do to maintain
  homeostasis?

Grow, respond to the environment, transform
energy, and reproduce
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3. What does it mean that cells are specialized?

• Cells have different tasks or roles to carry out
  that require them to have a specific structure
• Ex Cilia on trachea cells

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4. What are 2 things that help cells communicate
and maintain homeostasis?

• Cellular junctions (connections to other cells)
• Receptors (molecule that other cells can bind to)