4'1 Intro to the Cell

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4.1 Intro to the Cell

• A cell is the smallest unit of matter that can
  carry on all the functions of Life.

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Discovery of the cell

• Hooke was the first to name the cell when he
  looked at cork under a microscope.
• Hooke observed dead cells cell walls 1665
• Van Leeuwenkoek was the first to observe living
  cells.

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The cell Theory

• Nearly 150 years after Hooke and Leeuwenhoek the
  cell theory was developed.
• All living things are composed of one or more
  cells
• Cells are the basic units of structure and
  function in an organism.
• Cells come from the reproduction of existing
  cells.

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Theory cont.

• Three German scientists made discoveries aiding
  the cell theory.
• Schleiden determined that all plants were made of
  cells
• Schwann determined that all animals were made of
  cells.
• Virchow while studying diseases stated that cells
  come from reproducing of cells.

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Cell Diversity

• Not all cells are the same they vary in size
  shape and function.
• Your body is made of 200 different types of cell.

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Cell Size

• Most cells can not be seen without a microscope.
• Size is limited by the ratio between volume and
  surface area.
• Volume increases faster than surface area.
• If a cell get too large it will not be able to
  obtain enough raw materials

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Shape

• Cells are not limited in their shapes.
• The shape of a cell is generally a side effect of
  the cells function.

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Internal Organization

• Many cells contain membrane bound structures
  called organelles.
• An organelle is a cell part that performs a
  specific function for the cell.
• The entire cell is surrounded by the cell
  membrane.
• Usually the largest organelle is the Nucleus an
  organelle that contains the DNA

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Types of Cells

• Cells with organelles and membrane bound
  structures are called Eukaryotes.
• Cells that do not contain the membrane structures
  are called Prokaryotes.
• Prokaryotes are usually smaller than Eukaryotes.
• Prokaryotes are placed into two of their own
  Kingdoms.
• Prokaryotes are generally unicellular.