A Panoramic View of the Cell

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A Panoramic View of the Cell

• Alexandria Cottrell
• Trey Peel

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Cell Size

• A cell can get too small to contain all the
  components necessary for life.
• As a cell gets larger, its surface area to volume
  ratio gets much smaller,

• Takes too long for substances diffusing into the
  cell at the membrane (e.g., nutrients or oxygen)
  to get to all parts of the cell.

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Cell Size contd

• Range of cell size is limited by metabolic
  requirements
• Lower limit
• Upper limit

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Lower Limits

• The lower limits are determined with the smallest
  size
• enough DNA to program metabolism
• enough ribosomes, enzymes and cellular components
  to sustain life and reproduce

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Upper Limits

• The upper limits of size are imposed by the
  surface area to volume ratio.
• With growth the volume increases faster than
  membrane surface
• Surface area of membrane must be large enough for
  the cell volume,
• In order to provide an adequate exchange surface

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Prokaryotic Cells

• Pro- before Karyon- nucleus
• Evolutionarily ancient
• First form of life on Earth for billions of years
  and first living organisms to evolve

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Prokaryotes Contd

• All bacteria and bacteria-like Archae are
  prokaryotic organisms
• Have only a plasma membrane- membrane on the
  outside that surrounds the cell
• Ex amoeba

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Eukaryotic cells

• Eu- true Karyon- nucleus
• Evolved from prokaryote-like predecessor
• Either single-celled or multi-celled

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Eukaryotes Contd

• More complex
• Contain internal membrane bound structures
• Can reproduce by either meiosis (sexual
  reproduction) or mitosis (cell division producing
  identical daughter cells)

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Compartmentalization

• Average eukaryotic cell has 1000X the volume of
  the average prokaryotic cell, but only 100SX the
  surface area.
• Eukaryotic cells compensate by having internal
  membranes which
• Partition the cell into compartments

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Compartment Contd

• Have unique lipid and protein compositions
  depending on their specific function
• May participate in metabolic reactions since many
  enzymes are incorporated directly into the
  membrane
• Provide localized environmental conditions
  necessary for specific metabolic processes
• Sequester reactions, so they may occur without
  interference from incompatible metabolic
  processes elsewhere in the cell