Cell Theory - Cell Theory All organisms are composed of...

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Cell Theory All organisms are composed of cells, and a cell is the smallest unit of living matter. Cells come only from preexisting cells. Major Kinds of Cells Prokaryotic Cells Bacteria are prokaryotes. Their cells are very small and very simple. They will be discussed later. Eukaryotic cells All other cells are eukaryotic cells. These include protists, fungi, plants, and animals. The diagram below shows evolutionary relationships between bacteria, archaea, and the four kingdoms of eukaryotic organisms. Eukaryotic Cells Cells contain structures called organelles . The structure and function of the major organelles found in eukaryotic cells are described below. Plasma membrane All cells are surrounded by a plasma membrane. It separates the contents of the cell from its environment and regulates the passage of molecules into and out of the cell. The membrane contains proteins that have a variety of functions. For example, some proteins are receptors which can detect the presence of certain kinds of molecules in the surrounding fluids. The function of membrane proteins will be discussed in more detail in the chapter on
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This note was uploaded on 11/10/2011 for the course BIOLOGY bi 101 taught by Professor - during the Fall '10 term at Montgomery.

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Cell Theory - Cell Theory All organisms are composed of...

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