Term
| What is the permeability of the membrane affected by? |
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Definition
Temperature- high temperature +membrane permeability because of greater kinetic energy for faster diffusion
Organic Solvent- Dissolve or emulsify phospholipids and denature proteins, disrupting the cell membrane creating gaps or holes and making it more porous. |
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Term
| What are the 6 methods of transport? |
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Definition
1.Diffusion
2.Facilitated transport
3.Co-transport
4.Active Transport
5.Bulk transport (endo/exocytosis)
6.Osmosis |
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Term
| Is diffusion passive or active? |
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Definition
| Passive- Doesn't require ATP |
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Term
| Describe movement of diffusion? |
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Definition
Movement of molecules or ions down a concentration gradient.
From higher to lower concentration. |
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Term
| 6 Factors affecting rate of diffusion and how? |
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Definition
1. Concentration Gradient- Larger the difference in conc. greater the rate of diffusion
2.Thickness of Surface- Shorter distance faster diffusion.
3.S.A. of membrane- larger the area faster the diffusion.
4.Size of diffusing Molecules-smaller molecules diffuse faster less kinetic energy is needed to move them.
5. Nature of diffusing molecules- Non-polar diffuse faster than polar
6.Temperature- Increased temp. faster rate of diffusion. |
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Term
| What is the equation for the rate of diffusion? |
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Definition
| RATE OF DIFFUSION= SURFACE AREA X DIFFERENCE IN CONCENTRATION/ LENGHT OF DIFFUSION PATH |
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Term
| What is facilitated diffusion? |
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Definition
| Uses channel or carrier proteins. |
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Term
| Is facilitated diffusion active or passive? |
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Definition
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Term
| What kind of molecules does facilitated diffusion transport? |
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Definition
| Polar molecules and ions. |
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Term
| Is facilitated diffusion faster than diffusion? Why? |
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Definition
| Yes because proteins provide an easier passage than direct travel through the bilayer. |
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Term
| What affects the rate of facilitated diffusion? |
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Definition
-Channel/Carrier protein availability:rate plateaus once all are occupied (saturated)
-Concentration Gradient:steeper gradient leads to faster diffusion. |
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Term
| What is a channel protein? |
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Definition
| Has a water-filled pore that attracts ions due to the hydrophilic nature. Only allows specific ions to pass through, opening and closing in response to cellular needs. |
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Term
| What is a carrier protein? |
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Definition
| Diffusion of large polar molecules by undergoing a shape change when the molecule attaches to its binding site. This allows the molecule to be released on the opposite side of the membrane. |
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Term
| What are gated protein channels? |
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Definition
| The open and close in response to specific change |
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Term
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Definition
| It moves multiple molecules or ions together across a membrane using a single protein transport molecule. |
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Term
| What are processes that involve uptake of Na+ and glucose by co-transport include? |
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Definition
1.Absorption in the small intestine (ileum)
2.Selective reabsorption of solutes in the proximal convoluted tubule. |
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Term
| What is active transport? |
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Definition
| Move ions and polar molecules that are insoluble in lipid against the concentration gradient |
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Term
| Does active transport require ATP? |
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Definition
| Yes but it still uses carrier proteins. |
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Term
| How can active transport be stopped? |
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Definition
| By respiration inhibitors. |
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Term
| How does active transport work? |
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Definition
1.A molecule binds to a specific carrier protein
2.A phosphate grp is transferred from ATP to the carrier protein.
3.The carrier protein changes shape (with ATP) transporting the bound molecule across the membrane.
4.The molecules is released into the cytoplasm the cell.
5.The carrier protein reverts to its original shape. |
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Term
| What are examples of processes that involve active transport? |
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Definition
-Nerve Impulse Transmission
-Reabsorption of glucose in the kidney
-Mineral ion uptake in plant roots
-Muscle contraction |
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Term
| Why are cells that perform active transport packed with mitochondria? |
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Definition
| to undergo aerobic respiration producing ATP energy for active transport. |
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Term
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Definition
| Cell transports materials in bulk into or out of cell. |
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Term
| Does bulk transport require ATP? |
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Definition
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Term
| How does exocytosis work? |
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Definition
| Vesicles formed in the Golgi Body, migrate to the plasma membrane, fuse with it and release their contents to the exterior of the cell. |
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Term
| What are the two types of endocytosis? |
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Definition
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Term
| How does endocytosis work? |
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Definition
1.The cell membrane folds around the solid material
2.A vesicle is created containing the solid material which will be destroyed by hydrolytic enzymes |
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Term
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Definition
| The diffusion of water from higher water potential to lower water potential across a selectively permeable membrane |
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Term
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Definition
| Tendency for water to leave a solution measured in kPa. |
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Term
| What does it mean when the water potential is high? |
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Definition
| Water leaves solution. High to Low. No solutes |
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Term
| What does it mean when the water potential is low? |
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Definition
| Water enters solution.Low to High. Many solutes. |
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Term
| What is the element with the highest water potential? |
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Definition
| Pure Water. Highest Value of 0kPa. |
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Term
| What happens if you add solute in water? |
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Definition
| The number of free water molecules is decreased, potential energy of H2O decreases and water potential becomes negative |
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Term
| What does Hypotonic mean? |
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Definition
| External solution is higher than the solution inside the cell |
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Term
| If external solution is higher than the solution inside the cell does water move in or out (hypotonic)? |
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Definition
| Water moves into the cell by osmosis |
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Term
| What does Hypertonic mean? |
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Definition
| External solution is lower than the solution inside the cell |
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Term
| If external solution is lower than the solution inside the cell does water move in or out? |
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Definition
| Water flows out of the cell by osmosis |
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Term
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Definition
Water potential of external solution is the same as the solution inside the cell.
There is no movement of water |
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Term
| What is the equation for water potential in plants? |
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Definition
| Water potential = Pressure potential + Solute potential |
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Term
| What does solute potential mean? |
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Definition
| Solutes in the vacuole and cytoplasm, it is the lowering of water potential due to the presence of solute molecules |
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Term
| What is pressure potential? |
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Definition
| The pressure exerted by the cell contents on the cell wall |
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Term
| When water enters the plant what does it cause? |
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Definition
| The vacuole and cytoplasm to swell making the cell turgid. |
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Term
| What is theoretical definition of incipient plasmolysis? |
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Definition
| The point at which the cell membrane is just about to come away from the cell wall |
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Term
| What is the experimental definition of plasmolysis? |
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Definition
| The point where 50% of the cells in a sample are plasmolysed. |
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Term
| What is the water potential of cells at incipient plasmolysis? |
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Definition
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Term
| What happens to the plant cell when it's in a hypotonic solution? |
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Definition
| It becomes turgid, cell wall prevents it from bursting |
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Term
| What happens to the plant cell when it's in a hypertonic solution? |
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Definition
| Vacuole shrinks, the cell becomes plasmolysed. |
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Term
| What happens to animal cell when in hypotonic solution? |
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Definition
Ipotonico-i=into the cell
The cells swells and bursts |
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Term
| What happens to animal cell when in hypertonic solution? |
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Definition
| Water leaves the cell= crenates and shrinks |
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Term
| Does co-transport require ATP? |
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Definition
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Term
| Note the application graphs. |
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Definition
| WHITEBORAD-APPLICATION GRAPHS FROM CELL TRANSPORT. |
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