The Cell

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The Cell
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Early 17th Century

• Before the 17th century no one knew that cells
  existed because most cells are to small to be
  seen with the naked eye
• Cell were finally seen with the invention of the
  microscope ( one of the first was made by Anton
  Leeuwenhoek)
• Leeuwenhoek was the first person to observe and
  describe microscopic organisms

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Early 17th Century

• Robert Hooke described the empty chambers of a
  cork as a cell
• These observations were ignored for almost 2
  centuries
• With the combined work of scientists Scheiden,
  Schwann and Virchow came the modern Cell theory

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The Cell Theory

• Made up of 3 basic principals
• Cells are the basic units of life
• All organisms are made up of one or more cells
• All cells arise form preexisting cells
• Very important because it emphasizes the
  similarities of all living things

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Cell Diversity

• Not all cells are alike. 
• Even cells within the same organism show Enormous
  Diversity in size, shape, and internal
  organization. 
• ( these 3 things have everything to do with
  the cell function)
• ( Your body contains at least 200 different
  cell types. )

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Parts of the CellCell membrane

• A thin layer of lipid and protein that seperates
  the cells contents from the world around it.
• Consists of two layers therefore called a
  bilayer.
• Because the membrane lets things move into and
  out of it and has a moasic of proteins in it,
  scientists call the modern view of the membrane
  the fluid mosaic model.

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Parts of the CellNucleus

• The control center of the cell
• Most cells have only one nucleus, but some have
  more than one.
• Chromosomes are contained here ( where DNA is
  found)
• Nucleoli ( nucleolus) the place where ribosomes
  are made

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Parts of the CellCytoplasm

• Everything between the cell membrane and the
  nucleus
• Consists of 2 main parts
• Cytosol the jellylike mixture that consists
  mostly of water, protein, carbs and misc organic
  molecules.
• Organelles the structures that work like
  miniature organs, carrying out specific functions
  in the cell

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Parts of the CellRibosomes

• Unlike most other organelles, ribosomes are not
  surrounded by a membrane.
• The place where proteins are made
• The most numerous organelles in almost all cells.
  
• Some are free in the cytoplasm others line the
  membranes of ROUGH ENDOPLASMIC RETICULUM.

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Parts of the CellEndoplasmic Recticulum

• A system of membranous tubules and sacs.
• Functions as path along which molecules move
  from one part of the cell to another.
• Poisons, waste, and other toxic chemicals are
  made harmless here
• An extensive network of membranes that connect
  the nuclear envelope to the cell membrane
• Transports materials through the cell.
• Can be ROUGH OR SMOOTH.
• A. ROUGH is studded with
• RIBOSOMES
• B. SMOOTH IS NOT
• covered with RIBOSOMES

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Parts of the CellMitochondria

• Found scattered throughout the cytosol, and are
  relatively large organelles
• The "POWERHOUSE" of the cell. The place
• where energy is made, known as ATP.
• Have their own DNA
• Usually more numerous in cells that have a high
  energy requirement (Your muscle cells contain a
  large number of mitochondria)

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Parts of the CellLysosomes

• Small spherical organelles that enclose
  hydrolytic enzymes within a single membrane.
• The site of food digestion in the cell.
• Formed from pieces of the GOLGI APPARATUS that
  break off.
• Common in the cells of Animals, Fungi, and
  Protists, But Rare in Plant Cells.

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Parts of the CellGolgi apparatus

• The processing, packaging and secreting organelle
  of the cell.
• A system of membranes, made of flattened sac like
  structures
• Works closely with the ER, the Golgi Apparatus
  modifies proteins for export by the cell.