Bio ch 9 key terms
Terms
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- phospholipid
- Lipids with an attached phosphate group.
- selective permeability
- Feature the plasma membrane that maintains the cell's homeostasis by allowing some molecules into the cell while keeping others out.
- exocytosis
- Active transport process by which materials are expelled or secreted from a cell.
- facilitated diffusion
- Passive transport of materials across a plasma membrane by transport proteins embedded in the plasma membrane.
- transport protein
- Proteins that span the plasma membrane creating a selectively permeable membrane that regulates which molecules enter and leave a cell.
- fluid mosaic model
- Structural model of the plasma membrane where molecules are free to move sideways within a lipid bilayer.
- turgor pressure
- internal pressure of a cell due to water held there by osmotic pressure
- endocytosis
- Active transport process where a cell engulfs materials with a portion of the cell's plasma membrane and releases the contents inside of the cell.
- contraxtile vacuole
- organelle of some protists that collects excess water from the cell, then contracts and expells the water through the plasma membrane pore
- hypertonic
- In cells, solution in which the concentration of dissolved substances outside the cell is higher than the concentration inside the cell, causing a cell to shrink as water leaves.
- diffusion
- Net, random movement of particles from an area of higher concentration to an area of lower concentration, eventually resulting in even distribution.
- plasmolysis
- process resulting from a drop in turgor pressure as a result of water loss in a cell, causing the plasma membrane to shrink away from the cell wall
- hypotonic
- In cells, solution in which the concentration of dissolved materials is lower in the solution outside the cell than the concentration inside the cell, causing the cell to swell.
- isotonic
- In cells, solution in which the concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside the cell.
- dynamic equilibrium
- Result of diffusion where there is continuous movement of particles but no overall change in concentration.
- passive transport
- In cells, movement of particles across cell membranes by diffusion or osmosis; requires no expenditure of energy by the cell.
- osmosis
- Diffusion of water through a selectively permeable membrane depending on the concentration of solutes on either side of the membrane.