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11 Cards in this Set
- Front
- Back
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Ion
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An ion is an atom or group of atoms with a positive or negative electrical charge.
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What do your cells need to functions?
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Your cells need nutrients such as glucose, amino acids, and lipids to function.
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Plasma Membrane
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The job of the plasma membrane, the flexible boundary between the cell and its environment, is to allow a steady supply of glucose, amino acids, and lipids to come into the cell no matter what the external conditions are.
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What happens if a cell receives to many glucose, amino acids and lipids?
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Too many of any of these nutrients or other substances, especially ions, can be harmful to the cell. If levels become too high, the excess is removed through the plasma membrane.
Waste and other products also leave the cell through the plasma membrane. This process of maintaining balance in the cell's environment is called homeostasis. |
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What is Homeostasis?
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The process of maintaining balance in the cell's environment is called homeostasis.
If levels become too high, the excess is removed through the plasma membrane. Waste and other products also leave the cell through the plasma membrane. |
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What is the process called when the plasma membrane maintains homeostasis?
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Selective Permeability
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Selective Permeability
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A process in which a membrane allows some molecules to pass through while keeping others out.
Example: In you home, a screen in a window can perform selective permeability in a similar way. When you open the window, the screen lets fresh air in and keeps most insects out. |
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Some molecules, such as water, freely enter the cell through the plasma membrane.
True of False? |
True.
Other particles, such as sodium and calcium ions, must be allowed into the cell only at certain times, in certain amounts, and through certain channels. The plasma membrane must be selective in letting these enter. |
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Please describe the structure of a phospholipid...
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A phospholipid has a glycerol backbone, two fatty acid chains, and a phosphate group.
The plasma membrane is composed of a phospholipid bilayer, which has two layers of phospholipids back-to-back. |
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Phospholipid Bilayer
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*
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Water is
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Water is a key component of living organisms, both inside and outside the cell.
*The polar phosphate groups allows the cell membrane to interact with its watery environment because water is polar. * Fatty acid tails, on the other hand, avoid water. |
