General Biology 1401
Dr. Erin Schuenzel
February 13, 2014
Bacterial and Eukaryotic Cell Structures
All organisms are composed of cells which are characteristically microscope in size. Cell size is limited by the efficiency of diffusion across the plasma membrane. A typical eukaryotic cell is 10 to 100 micrometers in diameter opposed to prokaryotic cells are 1 to 10 micrometers in diameter. Bacterial and Eukaryotic cells display different cell organization in their size and structure, but despite this all they display basic structural similarities as well.
Differences between the structures of a bacterial and eukaryotic cell Bacteria cells are sheathed by a strong cell wall which is composed of peptidoglycan (polymer of sugar). The cell wall provides a structural strength, maintain its shape, and restricts the excessive or loss of water. Plants and Fungi also contain a strong cell wall but with a different chemical structure than peptidoglycan. Plants contain cellulose while fungi contains chitin fibers embedded in the matrix of other polysaccharides and proteins. Flagella are long, threadlike structures made of proteins used for movement. The bacteria’s rotary motor uses the energy stored in the gradient that transfers protons across the plasma membrane to power the movement of the flagellum. Eukaryotic cells have a completely different kind of flagellum, consisting of a circle of nine microtubule pairs surrounding two central microtubules. It has a whip movement rather than a rotate movement. Today the cells of many no longer maintain flagella but rather a similar short microtubule cilia. Cilia can be used to move cell and move fluids through water. In the bacterium, the chromosome consists of a single naked circle of DNA. In eukaryotes, each chromosome consists of a single linear DNA molecule and associated proteins.
The chromosomes contain hereditary information used to direct synthesis of proteins.
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