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| | A [[bacterium]] is a simple cell without a [[nucleus]] to protect its [[genetic information]]. | | A [[bacterium]] is a simple cell without a [[nucleus]] to protect its [[genetic information]]. |
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| − | A [[virus]] requires structures in a cell's [[cytoplasm]] to assemble copies of itself. | + | A [[virus]] requires the gene and protein building machinery in a cell to assemble copies of itself, however is not considered a cell by itself. |
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| | There is no consensus on the exact number of cells in a human body, though the number ranges from 10 to 100 trillion cells.<ref>Wile, Jay L. ''Exploring Creation With General Science''. Anderson: Apologia Educational Ministries, Inc. 2000</ref> | | There is no consensus on the exact number of cells in a human body, though the number ranges from 10 to 100 trillion cells.<ref>Wile, Jay L. ''Exploring Creation With General Science''. Anderson: Apologia Educational Ministries, Inc. 2000</ref> |
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| | ==Types of cells== | | ==Types of cells== |
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| − | There are two main types of cells: prokaryotic<ref name="spell">Also spelled ''procariotic'' or ''procaryotic'' and ''eucariotic'' and ''eucaryotic''.</ref> cells, which lack a nucleus, and eukaryotic<ref name="spell" /> cells, with a nucleus separated from cytoplasm by a nuclear membrane. | + | There are two main types of cells: prokaryotic<ref name="spell">Also spelled ''procariotic'' or ''procaryotic'' and ''eucariotic'' and ''eucaryotic''.</ref> cells, which lack a nucleus and certain [[organelles]], and eukaryotic<ref name="spell" /> cells, with a nucleus separated from cytoplasm by a nuclear membrane. |
| − | Each cell contains a complete copy of the organism's [[genome]]. | + | Each cell contains at least one complete copy of the organism's [[genome]]. |
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| | + | A prokaryotic cell lacks individual compartments however has a number of organelles that can also be found in the eukaryotic cell: |
| | + | * [[Ribosome]]s |
| | + | * [[Cell membrane]] |
| | + | * [[Cell wall]] |
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| | + | Prokaryotic cells may also have specialized features such as [[flagellum]] and [[pili]]. Prokaryotic cells can also carry accessory DNA known as [[plasmids]] that code for functions such as antibiotic resistance or the metabolism of lactose. Plasmids are stored separately from the organism's [[genome]] and are shared between other prokaryotic cells. |
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| | A eukaryotic cell is divided into a number of membrane bound compartments known as [[organelles]], each with its own structure and function. In a typical cell these components are: | | A eukaryotic cell is divided into a number of membrane bound compartments known as [[organelles]], each with its own structure and function. In a typical cell these components are: |
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| | * [[Golgi complex]] | | * [[Golgi complex]] |
| | * [[Mitochondrion]] | | * [[Mitochondrion]] |
| | + | * [[Chloroplast]] (in plants) |
| | * [[Lysosome]] | | * [[Lysosome]] |
| | * [[Peroxisome]] | | * [[Peroxisome]] |
| | * [[Vescicle]]s | | * [[Vescicle]]s |
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| − | A prokaryotic cell lacks individual compartments.
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| | ==Notes== | | ==Notes== |