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Please help!!!! PhysioEx 9.0 Exercise 1,2,3 post activity questions
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kelly2010
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Does anyone have the answers to the questions for the first three exercies PhysioEX 9.0...Exercise 1,2 and 3 and all the activities? I only need the answers to the post questions...

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Please help!!!! PhysioEx 9.0 Exercise 1,2,3 post activity questions
May 1, 2012

Have you completed anything from it so far? Ask a specific question, and we'll help to answer it.



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Please help!!!! PhysioEx 9.0 Exercise 1,2,3 post activity questions
May 25, 2012

CD Stimulation Cellular Transport:  Cell Transport Mechanisms and Permeability

Activity 1: Stimulating Dialysis (Simple Diffusion)

1. Describe two variables that affect the rate of diffusion.
The two variables that affect the rate of diffusion are:
•   The composition of the lipid layer, this content varies from tissue to tissue. For example kidney tissues have a high cholesterol content which makes them impermeable to water.
•   The size of the molecule, the larger the molecule the slower the rate of diffusion.

2. Why do you think the urea was not able to diffuse through 20 MWCO? How well did the results compare with your predictions?
The urea was not able to diffuse through the 20 MWCO because the membrane pores are too small and the urea molecules are large. The molecular weight of Urea is 60.07 g/mol which is too large thus the molecules were not able to pass through the pores of the 20 MWCO.
The results that I obtained from the experiment agreed with these predictions because urea was no able to diffuse through the 20 MWCO.

3. Describe the results of the attempts to diffuse glucose and albumin through the 200 MWCO membranes. How well did the results compare with your predictions?
Glucose was able to diffuse through the 200 MWCO membrane, however albumin was not able to diffuse through the 200 MWCO. This is due to the difference of the molecular weight between the two molecules. Glucose has a molecular weight of about 180 g/mol and albumin (a protein composed of 67 amino acids and each amino acid is 67 g/mol) has a molecular weight of (67 *135 g/mol) 9045 g/mol. By comparing these numerical values we can understand why albumin was not able to diffuse through the 200 MWCO.
The results that I obtained from the experiment supported these predictions because only glucose was able to diffuse through the 200 MWCO.

4. Put the following in order from smallest to largest molecular weight: glucose, sodium chloride, albumin, and urea.
Sodium chloride < urea < glucose < albumin.



Activity 2: Stimulated Facilitated Diffusion

1. Explain one way in which facilitated diffusion is the same as simple diffusion and one way in which it differs.
One way in which simple and facilitated diffusion are the same is that they both transport molecules along or down the concentration gradient of the solute and they do not require energy from an outside source.
One way in which simple and facilitated diffusion are different from each other is that facilitated diffusion requires a membrane bound carrier protein to aid in the transportation of a molecule across the membrane. However, simple diffusion occurs without the assistance of membrane proteins.

2. The larger value obtained when more glucose carriers were present corresponds to an increase in the rate of glucose transport. Explain why the rate increased. How well did the result compare with your predictions?
The rate of glucose transportation increased when more glucose carriers were present, since more glucose molecules could bind to the glucose carriers present. This resulted in an increase number of glucose molecules to cross the membrane.
The results from the experiment supported these predictions because as the number of glucose carriers increased the rate of glucose transportation via facilitated diffusion also increased.

3. Explain your prediction for the effect of Na+ Cl- might have on glucose transport. In other words, explain why you picked the choice you did. How well did the results compare with your predictions?
I believe that Na+ Cl- will not affect the rate of glucose transport, because Na+ Cl- is transported via simple diffusion which does not require a carrier protein. Therefore Na+ Cl- is completely independent from the glucose transport, so adding Na+ Cl- has no effect on the rate of glucose transport.
The results I obtained from the experiment supported these predictions because the presence of Na+ Cl- did not affect the rate of glucose transportation.






Activity 3: Stimulating Osmotic Pressure

1. Explain the effect that increasing the Na+ Cl- concentration had on osmotic pressure and why it has this effect? How did the results compare with your prediction?
Increasing the concentration Na+ Cl- molecules at a constant MWCO will result in an increased osmotic pressure. The high concentration of molecules in one side of the membrane results in an increased force of water movement to the high concentration side of the membrane which results in an increased osmotic pressure. 
Increasing the number of non-dissoluble molecules increases osmotic pressure. If the molecules are able to diffuse through the membrane then equilibrium will be reached and there will be no osmotic pressure generated. The Osmotic pressure would be zero if the Na+ Cl- concentrations of both side of the membrane are equal.
The results I obtained from the experiment supported these predictions because as we increased the concentration NaCl the osmotic pressure also increased. The Na+ Cl- molecules were able to diffuse through the 50 MWCO membranes, but not through the 20 MWCO. Adding more Na+ Cl- to the 20 MWCO membrane resulted in an increased osmotic pressure. But by adding the Na+ Cl- to the 50 MWCO membrane did not results in any pressure because the Na+ Cl- molecules were able to diffuse through the membrane.


2. Describe one way in which osmosis is similar to simple diffusion and one way in which it is different?
One way in which osmosis is similar to simple diffusion is that both processes are passive which means the molecules diffuse from an area of high concentration to an area of low concentration without the use of energy from the external source.
One way in which osmosis is different from simple diffusion is that in simple diffusion ions and molecules are transported across the membrane. However in osmosis only solvents (such as water) are being transported through a selectively permeable membrane.

3. Solutes are sometimes measured in miliosmoles. Explain the statement, "water chases miliosmoles ".
This statement means that as the solute concentration increases, the concentration of water decreases. Osmosis is the diffusion of a solvent such as water. Osmosis occurs whenever there is a difference of water concentrations between two sides of a membrane. The water diffuses to the side of the membrane which contains the highest concentration of solutes.


4. The conditions of 9 mM albumin in the left beaker and 10 mM glucose in the right beaker with the 200 MWCO membrane in place. Explain the results. How well did the results compare with your prediction?
The (10mM) glucose molecules were able to diffuse from the right beaker to the left beaker until equilibrium was reached, meaning that both the left and the right beaker contained the same concentration of glucose. The 9 Mm albumin was not able to diffuse through the 200 MWCO membrane thus it remained in the left beaker which resulted in a osmotic pressure of 153 mmHG.
The results from the experiment supported these predictions because glucose was able to diffuse through the 200 MWCO whereas albumin was not able which resulted in an osmotic pressure.

Activity 4: Stimulating Filteration

1. Explain in your own words why increasing the pore size increase the filtration rate. Use an analogy to support your statement. How well did the results compare with your prediction?
Increasing the pore size increases the filtration rate because more types of solutes and fluids are able to pass through the membrane.
An analogy that I would use to support this process is a coffee maker filter.
The coffee (solute or solvent) passes through a metal filter quicker than a paper filter because of the larger pore size of the metal filter.
The results of the experiment agreed with this prediction, because as MWCO (pore size of filters) increased the filtration rate of molecules also increased. 

2. Which solute did not appear in the filtrate using any of the membranes? Explain why?
Powdered charcoal was the only solute that did not filtrate using any of the membranes. The charcoal contains large molecules and therefore it is not able to pass through the pores of the membranes.

3. Why did increasing the pressure increase the filtration rate but not the concentration of solutes? How well did the results compare with your prediction?
Increasing the pressure increases the filtration rate since the molecules are able to pass through the membrane at a faster rate. However, it does not increase the concentration of solutes that passes through the membrane. This is because pressure is independent of the number of molecules present; therefore increasing the pressure will not affect the concentration of molecules.
The results I obtained from the experiment supported these predictions because as we increased the pressure the filtration rate increased as well but it had no effect on the concentration of the solute.

Activity 5: Stimulating Active Transport

1. Describe the significant of using 9 mM sodium chloride inside the cell and 6 mM potassium chloride outside the cell instead of other concentration ratios.
The significants of using 9 mM sodium chloride inside the cell and 6 mM potassium chloride outside the cell is that 3 Na+ ions are transported out of the cell for every 2 k+ ions that are transported in to the cell. This is significant because the ratio of 3:2 is the same as the ratio of 9 mM: 6 mM.

2. Explain why there was no sodium transport even though ATP was present. How well did the results compare with your predictions.
The reason that there was no sodium transport even though ATP was present is because in order for Na+/K+ pumps to function, both of these ions (Na+ and K+) must be present. In this stimulation there was no potassium (K+) present, therefore the Na+/K+ pump was not able to function.
The results I obtained from the experiment supported these predictions because there was no sodium transport with the presence of ATP when potassium was absent.

3. Explain why the addition of carriers had no effect on sodium and potassium transport? How well did the results compare with your predictions?
The addition of carriers did not have an effect on the sodium and potassium transport because the carriers are used to transport molecules such as glucose via facilitated diffusion with no input of energy from an external source.
Na+ and K+ ions are transported actively via Na+/K+ pumps against their concentration gradient. Therefore the addition of the carriers would have no effect on the transport of sodium and potassium ions.
The results I obtained from the experiment agreed with these predictions because the addition of carriers had no effect on the potassium and sodium ion transport.

4. Do you think glucose is being actively transported or transported by facilitated diffusion in this experiment? Explain your answer.
Glucose is being transported passively down its concentration gradient by facilitated diffusion because there was no ATP present. Therefore we can assume that glucose carriers were present to assist in the transportation of glucose molecules across the membrane.



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Please help!!!! PhysioEx 9.0 Exercise 1,2,3 post activity questions
Sep 20, 2012

Thanks this help alot



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Sep 20, 2012

I need this too, thanks.



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Oct 3, 2012

Thanks for all the help! Smile



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Oct 28, 2012

This is AWESOME! Thank you so much!  Congratulations



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Please help!!!! PhysioEx 9.0 Exercise 1,2,3 post activity questions
Jan 11, 2013

Hope this helps for Ex1

Edit (admin.): These attachments no longer work.



Attached file(s)* PEX-01-01.pdf (24.27 KB - downloaded 187 times.)
* PEX-01-02.pdf (28.43 KB - downloaded 108 times.)
* PEX-01-03.pdf (36.57 KB - downloaded 134 times.)
* PEX-01-04.pdf (57.92 KB - downloaded 46 times.)
* PEX-01-05.pdf (42.41 KB - downloaded 61 times.)
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Jan 21, 2013

thank you , very helpful!



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Jan 21, 2013

why can't I open the files?



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Jan 21, 2013

why can't I open the files?

Need a meaningful post!



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Jan 21, 2013

Thankyou, very helpful



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Thank you so much my dude !!



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Thank you so much!



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