Term
| how is the structure of a membrane related to its function |
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Definition
| cell membranes isolate cell contents while allowing communication with the environment |
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Term
| 5 functions of the plasma membrane |
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Definition
1. isolates the cell's contents from the external environment
2. regulates the exchange of essential substances
3. allows communication between cells
4. creates attachments within and between cells
5. regulates biochemical reactions |
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Term
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Definition
| carbohydrates attached to proteins on their outer membrane surface |
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Term
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Definition
| trigger cellular responses upon binding of specific molecules, such as hormones, sent by other cells |
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Term
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Definition
| glycoproteins that serve as identification tags on the surface of a cell |
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Term
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Definition
| are proteins that promote chemical reactions that synthesize or break apart biological molecules |
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Term
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Definition
| anchor the cell membrane to the inner cytoskeleton to proteins outside the cell and to other cells |
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Term
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Definition
| regulate the movement of hydrophilic molecules through the plasma membrane |
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Term
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Definition
| form channels whose central pores allow specific ions or water molecules to pass through the membrane |
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Term
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Definition
| have binding sites that can temporarily attach to specific molecule on one side of the membrane and then move them through the membrane to the other side |
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Term
| how do substances move across membranes? |
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Definition
| molecules in fluids move in response to gradients |
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Term
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Definition
| a substance whose molecules can flow past one another and have no defined space |
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Term
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Definition
| a fluid capable of dissolving another substance |
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Term
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Definition
| a substance that can be dissolved in a solvent |
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Term
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Definition
| defines the amount of solute in a given amount of solvent |
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Term
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Definition
| physical difference in temperature, pressure, charge, or concentration of a particular substance in a fluid between two adjoining regions of space |
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Term
| how do gradients cause molecules to move from one place to another |
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Definition
| cells use energy and cell membrane proteins to generate concentration gradients of various molecules and ions dissolved in their cytoplasm |
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Term
| why do gradients cause molecules to move from one place to another? |
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Definition
| molecules and ions in solution are in constant random motion which produces a net movement form regions of high concentration to regions of low concentration by a process called diffusion. The higher the temperature, the higher the rate of random motion |
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Term
| movement through membranes occurs by: |
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Definition
| passive transport and energy requiring transport |
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Term
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Definition
| diffusion of substances across cell membranes down concentration gradients |
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Term
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Definition
| substances move down their concentration gradient across a membrane |
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Term
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Definition
| water soluble molecules like ions, amino acids, and sugars diffuse down their concentration gradients with the aid of channel and carrier transport proteins |
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Term
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Definition
| specialized water channel proteins |
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Term
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Definition
| the diffusion of water across selectively permeable membranes |
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Term
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Definition
| from a region of high water concentration to a region of low water concentration across a membrane |
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Term
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Definition
| reduce the concentration of free water molecules in a solution because dissolved substances displace water molecules |
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Term
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Definition
| have equal concentrations of water and equal concentrations of dissolved substances (no net water movement occurs across the membrane) |
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Term
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Definition
| is one with a greater solute concentration (water moves across a membrane away from the hypotonic solution) |
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Term
| energy requiring transport |
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Definition
| transport that requires the use of cellular energy |
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Term
| two types of movement across the plasma membrane |
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Definition
| passive transport and osmosis |
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Term
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Definition
| membrane proteins use cellular energy to move molecules or ions across plasma membranes against their concentration gradients |
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Term
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Definition
| cells engulf particles and transport them using vesicles |
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Term
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Definition
| moves material out of the cell |
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Term
| as a spherical cell enlarges, |
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Definition
| its innermost parts get farther away from the plasma membrane |
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Term
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Definition
| diffusion can take too long to supply important processes deep within the cell |
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Term
| a cell's volume increases... |
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Definition
| more rapidly than its surface |
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Term
| how do nerve and muscle cells and microvilli overcome size restraints? |
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Definition
| they elongate, thus keeping the ratio of surface area to volume relatively high |
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Term
| how do specialized junctions allow cells to connect and communicate |
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Definition
| desmosomes, tight junctions,gap junctions, and plamodesmata |
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Term
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Definition
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Term
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Definition
| found where cells need to adhere tightly together under the stress of movement |
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