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10 Cards in this Set
- Front
- Back
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What are colloids?
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Particles that are small enough to remain in a stable suspension but to large to be completely dissolved.
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Why are colloids important and what are two properties of this importance?
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Their properties allow them to retain mineral nutrients for release into the soil solution for uptake by the roots.
1.) Their high surface area per unit mass 2.) Their large number of urface changes, which can reversibly bind large numbers of ions. |
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Soil particles are predominently charged positive or negative? Why?
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Negative, surface oxygen atoms
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Mineral ____ adsorb to surfaces of negative charged soil particles forming a reserve. Mineral ____ adsorb porrly, allowing them to be leached out of the ground.
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Cations, Anions
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Main losses of nutrients in agricultural occur because of? How is it increased and what happens when it does and what can be done to prevent it?
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Leaching. Acidic soils increase leaching of cations. Causes could be acidic rain or the plant producing H+ ions to aid itself in absorbing certain ions. Adding lime to the soil can increase the pH. If the pH needs to be decreased, adding sulfur will work.
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3 mechanisms for passive and active exchange of ions across biological membranes
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1.) Simple diffusion (few biologically important solutes are non-polar enough to use this mechanism)
2.) Facilitated diffusion 3.) Active Transport |
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What do channel proteins rely on for transport specificity? Does this make it passive or active transport?
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Pore size and electric charge. Passive.
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How do carrier proteins work compared to channel proteins? What mechanism(s) does it use?
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They bind the particular solute to be transported, instead of letting it pass through. The binding induces a protein conformational change which moves the solute to the other side of the membrane for release. Can use both facilitated diffusion and active transport. If using active transport, the carrier protein is known as a PUMP.
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Which allows for rapid transport and which allows for more specific transport, Carrier proteins and/or Channel Proteins?
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Channel proteins allow for rapid transport while Carrier proteins allow for more specific transport.
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How does active transport work?
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Always coupled with an energy source, such as ATP hydrolysis and always mediated by a carrier protein, which moves solutes across the membrane against a chemical gradient.
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