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Questions and Answers
What is the primary function of the cell membrane?
What is the primary function of the cell membrane?
What is the natural tendency of molecules in simple diffusion?
What is the natural tendency of molecules in simple diffusion?
What is the result of molecules moving from a high concentration to a low concentration?
What is the result of molecules moving from a high concentration to a low concentration?
What is the term for the process of molecules moving from areas of high concentration to areas of low concentration?
What is the term for the process of molecules moving from areas of high concentration to areas of low concentration?
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What is the role of the cell membrane in maintaining homeostasis?
What is the role of the cell membrane in maintaining homeostasis?
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What is an example of diffusion in everyday life?
What is an example of diffusion in everyday life?
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What is the characteristic of the cell membrane that allows it to control the movement of molecules?
What is the characteristic of the cell membrane that allows it to control the movement of molecules?
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What is the term for the ability of the cell to maintain a balance of conditions inside the cell?
What is the term for the ability of the cell to maintain a balance of conditions inside the cell?
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Study Notes
How Molecules Enter and Exit Cells
- The cell membrane determines what enters and exits the cell, and it is how the cell interacts with its environment.
- The cell membrane is a phospholipid bilayer structure that provides a semipermeable barrier between the inside and the outside of the cell.
Cell Survival
- The cell needs some substances to be brought into the cell and some to be moved out of the cell in order to survive.
- The cell membrane controls the transport of molecules between the outside environment and the interior of the cell to maintain homeostasis.
Homeostasis
- Homeostasis is the balance of conditions inside the cell for normal function.
- The cell membrane plays a crucial role in helping the cell maintain homeostasis.
Passive/Simple Diffusion
- Passive diffusion is the natural tendency of molecules to spread out to fill up the spaces available to them.
- In simple diffusion, molecules spontaneously move from areas of high concentration to areas of low concentration due to random movement.
- Diffusion happens when molecules move from a high concentration to a low concentration, moving down or with their concentration gradient.
- Examples of diffusion include:
- The diffusion of a drop of ink placed in a beaker of water.
- Smelling cookies baking the moment you walk into a kitchen.
- Adding sugar to your coffee and the sugar molecules spreading out as they dissolve.
- Leaving a can of soda open for a long time, and the carbon dioxide "fizz" diffusing into the air.
- Diffusion can also happen across a membrane, where molecules spread into or out of a cell, following their natural tendency to spread out, moving down their concentration gradient.
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Description
Learn how molecules enter and exit cells through the cell membrane, a semipermeable barrier that allows selective movement of substances in and out of the cell.
