Term
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Definition
- requires energy because molecule must be pumped across a membrane gradient
- allows cell to maintain internal concentrations of small molecules that differ from concentrations in its environment
- energy is supplied by ATP
- ATP transfers its terminal phosphate group directly to protein
- this induces the protein to change its chape in a matter that moves solute bound to the protein across the membrane
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Term
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Definition
- a channel protein in the plasma membrane of a plant, animal or microorganism cell that specifically facilitates osmosis, the diffusion of water across the membrane
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Term
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Definition
- the transport of large molecules in vesicles
- exocytosis
- endocytosis
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Term
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Definition
- interaction between cells
- intercellular joining
- a cells ability to distinguish one type of neighboring cell from another
- some glycogen proteins act as tags to be recognized
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Term
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Definition
- part of passive transport
- does not have a continuously open channel
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Term
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Definition
| a region along which the density of a chemical substance increases or decreases |
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Term
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Definition
- another active transport mechanism
- the coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against it's own concentration gradient
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Term
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Definition
- Aquaporin
- facilitates transport of water molecules
- proteins form tunnels to allow specific molecules to go through
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Term
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Definition
- transports materials out of the cell
- phagocytosis
- pinocytosis
- receptor mediated endocytosis
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Term
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Definition
| transports material into the cell |
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Term
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Definition
- limp
- lacking in stiffness or firmness
- a walled cell is flaccid in surroundings where there is no tendency for water to enter the cell
- happens to isotonic
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Term
| Fluid Mosaic Model of Membrane Structure |
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Definition
- mosaic: random organization of proteins
- fluid: fluidity of phospholipids to move around; membrane is not rigid
- lateral phospholipid movement is common
- flip-flop movement is uncommon because it takes a lot more work for the hydrophillic ends to pass through the hydrophobic area
- fluidity of membrane is adjusted by the phospholipid composition
- saturated vs. unsaturated
- unsaturdated hydrocarbon tails have more fluiditybecause they do not stack as well as saturated
- cholesterol can affect fluidity by lowering changes in temperature
- ex: fluidity increases at high temperature and decreases at low temperature
- Right fluidity allows materials to pass through membrane and to insert proteins into proper place
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Term
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Definition
| ability of phospholipids to move around |
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Term
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Definition
| the phenomenon where many polar molecules and ions impeded by the lipid bilayer of the membrane diffuse passively with the help of transport proteins that span the membrane |
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Term
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Definition
- water enters the cell faster then it leaves
- cell becomes turgid (bloated)
- if you place cell in an environment where there is more solute on the inside then the outside and so water enters the cell so it can balance out the concentration of solute
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Term
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Definition
- water leaves the cell faster then it enters
- cell shrivels or dehydrates
- if you place cell in an environment where there is more solute on outside then inside, water will escape to balance out concentration
- plasmolysis
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Term
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Definition
- cell is immersed into a solution that is the same as cell
- movement of water is constant and nothing happens to cell
- flaccid
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Term
| Integral membrane protein |
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Definition
- penetrate the hydrophobic core of the lipid bilayer
- extend only partway into the lipid bilayer
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Term
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Definition
| the process of disintegration or breaking apart of large molecules |
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Term
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Definition
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Term
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Definition
| The charge difference between a cell's cytosol and the extracellular fluid, due to the differential distribution of ions. Membrane potentisla affects the activity of excitable cells and the transmembrane movement of all charged substances. |
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Term
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Definition
- water diffuses across a membrane to equilibrate the concentration of solutes on each side of the membrane
- it moves from region of lower solute concentration to region of higher solute concentration
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Term
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Definition
- does not require energy
- simple diffusion
- Faciliated diffusion
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Term
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Definition
- molecules move from regions of high concentration to regions of low concentration
- molecules are always in constant motion because of their inherent thermal energy
- cell membrane acts as selectively premeable and small uncharged membranes move through the membrane
- charged, polar or large molecules cannot go through
- osmosis
- hypotonic
- hypertonic
- isotonic
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Term
| Peripheral Membrane proteins |
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Definition
- are not embedded into the lipid bilayer
- are bound to the surface or the membrane
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Term
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Definition
- a type of endocytosis
- bringing food into the cell
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Term
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Definition
- type of endocytosis
- bringing fluids into the cell
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Term
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Definition
- made up of glycerol joined to 2 fatty acids and a phosphate group
- hydrocarbon chains of fatty acids act as a nonpolar, hydrophobic tail, while the rest of the molecule acts as a polar hydrophillic head.
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Term
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Definition
| occurs when a cell begins to shrivel because of dehydration and the membrane begins to detach from the cell wall |
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Term
| Receptor Mediated Endocytosis |
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Definition
- very selective of what is brought into the cell
- receptors detect what they want
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Term
| Selectively premeable membrane |
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Definition
| cell membrane that only lets certain things in and out of the cell |
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Term
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Definition
| when a receptor site is stimulated and then sends out a signal to the internal part of the cell through internal interaction which induces a response |
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Term
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Definition
- exchanges sodium ions with potassium ions across plasma membranes of animal cells
- difference in ion concentrations on different sides of the membrane results in different overall electrical charges on each side of the membrane
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Term
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Definition
| The ability of a solution surrounding a cell, to be able to use that cell to gain or lose water |
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