Biology: Tissues, Organs, and Systems of Living Things

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Biology Tissues, Organs, and Systems of Living
Things
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ALL ABOUT CELLS
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A Short History Lesson

• Robert Hooke (1665) first discovered cells - cork
  
• Schwann and Schleiden (1838) first hypothesized
  that all organisms are composed of cells
• First to distinguish between plant and animal
  cells

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• It has been estimated that there are 10 times
  more cells in the human body than stars in the
  Milky Way.

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Cell Theory

• All living things composed of cells
• Cells are basic unit of living organisms
• All cells come from existing cells

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Cell Theory

• The Human body is estimated to have 100 trillion
  cells.
• Cells are specialized to perform various tasks.
• Examples
• Nerve Cells transmit electrochemical messages.
• Muscle Cells contract.
• All cells
• Digest nutrients
• Excrete wastes
• Reproduce

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Prokaryotic vs. Eukaryotic
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(No Transcript)
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Prokaryotic Cells

• No internal compartments
• No organelles
• 1-celled organisms
• Eg. bacteria

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Prokaryotic Cells

• Smaller
• DNA located in nucleoid region
• May not need O2

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Eukaryotic Cells

• Have internal compartments
• Have organelles
• 1-celled or multi-celled organisms
• Eg. Plant cell

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Eukaryotic Cells

• Larger cells
• DNA located in the nucleus
• Usually need O2

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Ticket out of Class!

• On a scrap piece of paper provided answer the
  following question
• Are your cells prokaryotic or eukaryotic?
  Explain.
• Hand the paper in, with your name on it
• Homework Textbook Page 32 Questions 1 and 3

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