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Cell Transport Mechanisms and Permeability Essay

Purpose

The purpose of this lab is to teach me simulating dialysis, simulating facilitated diffusion, simulating osmotic pressure, simulating filtration, and simulating active transport.

Hypothesis

If I increase the concentration of sodium chloride from 9mM to 18mM in the left beaker, then the rate of diffusion will increase, because concentration is a variable that affects the rate of diffusion.

Materials & Methods

Materials:
1.Computer

Methods:
1.Access PhysioEx through Mastering A&P and complete the activities and lab experiment under the Cell Transport Mechanisms and Permeability section. 2.Copy and paste all of the activities completed under the Cell Transport Mechanisms and Permeability section into a blank document. 3.In the blank document where you posted your completed activities, complete a lab report using the scientific method format. 4.Submit the completed lab report using the drop down box provided in Blackboard.

Results

Exercise 1: Cell Transport Mechanisms and Permeability: Activity 1: Simulating Dialysis (Simple Diffusion) Lab Report

Pre-lab Quiz Results
You scored 75% by answering 3 out of 4 questions correctly.

1. The driving force for diffusion is
Your answer : d. the dialysis membrane.
Correct answer: b. the kinetic energy of the molecules in motion.

2. In diffusion, molecules move
You correctly answered: a. from high concentration to low concentration.

3. Which of the following dialysis membranes has the largest pore size? You correctly answered: d. 200 MWCO

4. Avogadro’s number is a constant for the number of You correctly answered: b. molecules.

Experiment Results
Predict Question:
Predict Question 1: The molecular weight of urea is 60.07. Do you think urea will diffuse through the 20 MWCO membrane? Your answer : c. No, not at all.

Predict Question 2: Recall that glucose is a monosaccharide, albumin is a protein with 607 amino acids, and the average molecular weight of a single amino acid is 135 g/mole.

Which of the following will be able to diffuse through the 200 MWCO membrane? Your answer : a. neither glucose nor albumin

Stop & Think Questions:
The reason sodium chloride didn’t diffuse left to right is that You correctly answered: c. the membrane pore size was too small.

Glucose is a six-carbon sugar. Albumin is a protein with 607 amino acids. The average molecular weight of a single amino acid is 135 g/mole. There is no reason to run these solutes at the 20 MWCO because You correctly answered: d. glucose and albumin are both too large to pass.

The rate of diffusion for urea
You correctly answered: b. is slower than that for sodium because urea is a larger molecule.

Experiment Data:

Solute |MWCO |Left Solute Concentration |Right Solute Concentration |Average Diffusion Rate | Na+ Cl- |20 |0.00 |9.00 |0.0000 |
Urea |20 |0.00 |0.00 |0.0000 |
Albumin |20 |0.00 |0.00 |0.0000 |
Glucose |20 |0.00 |0.00 |0.0000 |
Na+ Cl- |20 |0.00 |0.00 |0.0000 |
Urea |20 |9.00 |0.00 |0.0000 |
Albumin |20 |0.00 |0.00 |0.0000 |
Glucose |20 |0.00 |0.00 |0.0000 |
Na+ Cl- |50 |9.00 |0.00 |0.0150 |
Urea |50 |0.00 |0.00 |0.0000 |
Albumin |50 |0.00 |0.00 |0.0000 |
Glucose |50 |0.00 |0.00 |0.0000 |
Na+ Cl- |50 |18.00 |0.00 |0.0273 |
Urea |50 |0.00 |0.00 |0.0000 |
Albumin |50 |0.00 |0.00 |0.0000 |
Glucose |50 |0.00 |0.00 |0.0000 |
Na+ Cl- |100 |9.00 |0.00 |0.0150 |
Urea |100 |0.00 |0.00 |0.0000 |
Albumin |100 |0.00 |0.00 |0.0000 |
Glucose |100 |0.00 |0.00 |0.0000 |
Na+ Cl- |100 |0.00 |0.00 |0.0000 |
Urea |100 |9.00 |0.00 |0.0094 |

Solute |MWCO |Left Solute Concentration |Right Solute Concentration |Average Diffusion Rate | Albumin |100 |0.00 |0.00 |0.0000 |
Glucose |100 |0.00 |0.00 |0.0000 |
Na+ Cl- |200 |0.00 |0.00 |0.0000 |
Urea |200 |0.00 |0.00 |0.0000 |
Albumin |200 |0.00 |0.00 |0.0000 |
Glucose |200 |9.00 |0.00 |0.0042 |
Na+ Cl- |200 |0.00 |0.00 |0.0000 |
Urea |200 |0.00 |0.00 |0.0000 |
Albumin |200 |9.00 |0.00 |0.0000 |
Glucose |200 |0.00 |0.00 |0.0000 |

Post-lab Quiz Results
You scored 75% by answering 3 out of 4 questions correctly.

1. The effect of increasing the concentration of sodium chloride from 9 mM to 18 mM in the left beaker was to You correctly answered: b. increase the rate of diffusion.

2. Describe the difference between the rate of diffusion seen for sodium and urea. You correctly answered: c. Urea diffused more slowly because it is larger than sodium.

3. Which of the following solutes did not pass through any of the membranes? Your answer: c. urea
Correct answer: b. albumin

4. When diffusion stops, we say the solution has reached
You correctly answered: a. equilibrium.

Review Sheet Results
1. Describe two variables that affect the rate of diffusion. Your answer:
The two variables that affect the rate of diffusion are the size of material and the concentration of gradient.

2. Why do you think the urea was not able to diffuse through the 20 MWCO membrane? How well did the results compare with your prediction? Your answer:
I think that the urea was not able to diffuse through the 20 MWCO membrane because urea was too big to pass through thw 20 MWCO membrane. My prediction
matched the results.

3. Describe the results of the attempts to diffuse glucose and albumin through the 200 MWCO membrane. How well did the results compare with your prediction? Your answer:
Glucose was able to diffuse through the 200 MWCO membrane, while there was no diffusion of albumin. The results and my prediction did not match up, because I predicted that neither glucose, nor albumin would be able to diffuse through the 200 MWCO membrane.

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

Conclusion

My hypothesis was proven to be correct, because when the concentration of sodium chloride was increased from 9mM to 18mM in the left beaker, the rate of diffusion did increase. When the 20 MWCO membrane was in the membrane holder between the two beakers, and I increased the Na+Cl- concentration to 9.00mM and the right beaker was fill with deionized water, there was no diffusion. After flushing the two beakers and increasing the urea concentration to 9.00mM in the left beaker and filling the right beaker with deionized water, there was no diffusion. When the 50 MWCO membrane was put in the membrane holder between the two beakers, and I increased Na+Cl- in the left beaker to 18.00mM and the right beaker was filled with deionized water, the average rate of diffusion was 0.0273. I then flushed both beakers, took out the 50 MWCO membrane and replaced it with 100 MWCO membrane and increased the left beaker to 9.00mM of Na+cl- solution and the average rate of diffusion was then 0.0150. I flushed both beakers, then filled the left beaker with 9.00mM of urea solution and filled the right beaker with deionized water, which caused the average diffusion rate to be 0.0094. After flushing the two beakers again, I replaced the 100 MWCO beaker with a 200 MWCO beaker. I then filled the left beaker to 9.00mM of glucose and the right beaker with deionized water, the average rate of
diffusion was 0.0042. After flushing the two beakers and filling the left beaker to 9.00mM of albumin and the right beaker with deionized water, there was no diffusion.


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