Cell Transport Mechanisms And Permeability

This essay sample essay on Cell Transport Mechanisms And Permeability offers an extensive list of facts and arguments related to it. The essay’s introduction, body paragraphs and the conclusion are provided below.

This enables nutrients to enter the cell, while keeping unwanted substances out. Active transport requires that the cell provide energy in the form of TAP to power the transport of substances through the membrane. During passive transport the substances move through the plasma membrane because of pressure or concentration differences between the interior and exterior of the cell.

Facilitated diffusion relies on carrier proteins, and occurs when molecules are either not lipid soluble or are too large to pass through the pores of the membrane.

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Solutes have to combine with the carrier proteins in the membrane, ND then they can be transported down the concentration gradient. Filtration is the movement of solute and water molecules across a membrane due to a pressure gradient. Active transport occurs when substances are not moving along the concentration gradient, are not lipid soluble, or are too large to pass through the membrane’s pores.

The first experiment involves the facilitated diffusion of glucose. This simulation depicts the varied rates of diffusion for glucose with differing numbers of glucose carrier proteins.

As the number of glucose carrier proteins increases the rate of diffusion also increases. The second experiment simulates alteration of sodium, urea, glucose, and powdered charcoal. These substances filtrate across the membrane as a result of pressure differences between the two sides of the membrane. During simulation, the pressure is altered to examine how rate of diffusion changes with the pressure change. Experiment three depicts the active transport of An+ and K+ across the membrane using sodium- potassium pumps and AT P. TAP is altered between simulation runs to see how this affects the rates.

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Materials Human Anatomy & Physiology Laboratory Manuel Physique 8. 0 Physiology Lab Simulation Program Computer Method Activity 2: Simulating Facilitated Diffusion In the stimulating facilitated diffusion experiment, I used the Physique 8. 0 Physiology Lab Simulation Program on a computer and the Human Anatomy and Physiology Laboratory Manuel. I set the glucose carrier proteins in the membrane to 500. I adjusted the glucose concentration in the left beaker to 2. 0 mm and dispensed only denizen water in the right beaker. The timer was set for 60 minutes.

After clicking the start button, I was able to observe concentration changes between the two beakers. This same procedure was done two more times, but I changed the number of carrier proteins to 700 on Run 2 and then 900 in Run 3. The next three simulation runs were done using 8. 0 mm of glucose concentration in the left beaker and denizen water only in the right beaker. Run 4 was done using 500 carrier proteins, Run 5 used 700 carrier proteins, and Run 6 used 900 carrier proteins in the membrane. All data was recorded. Activity 4: Simulating Filtration In the simulating filtration experiment, I used the Physique 8. Physiology Lab Simulation Program on a computer and the Human Anatomy and Physiology Laboratory Manuel. I adjusted the dialysis membrane in the first run to 20 MOOCOW. The membrane was placed between the top and bottom beaker. I then dispensed 5. 0 MGM/ml of Nasal, urea, glucose, and powdered charcoal into the top beaker. The pressure unit atop the beaker was set to 50 meg. The timer was set to 60 minutes, and then the start button was pushed to begin. After simulation, the membrane was analyzed to detect solute residue using the Membrane Residue Analysis Unit. Simulation Runs 2-4 were also done the same way using 50 meg of pressure and 5. MGM/ml of Nasal, urea, glucose, and powdered charcoal dispensed in the top beaker. However, with each run, I changed dialysis membranes. During Run 2, I used the 50 MOOCOW dialysis membrane, Run 3 used 100 MOOCOW, and Run 4 used 200 MOOCOW. After each run the Membrane Residue Analysis Unit was used to detect any residue present on the membrane, and all data was recorded. Activity 5: Simulating Active Transport In the stimulating active transport experiment, I used the Physique 8. 0 Physiology Laboratory Manuel. I used the membrane builder to adjust the sodium-potassium pumps to 500 and the glucose carriers to 500.

The membrane was placed between the two beakers. The Nasal concentration in the left beaker was set to 9. Mm and dispensed. KICK concentration in the right beaker was set to 6. 00 mm and dispensed. The TAP dispenser on top of the beakers was set to 1. 0 MM and dispensed. The timer was set to 60 minutes. I pushed the start button, and watched as solute concentrations of sodium and potassium changed between the two beakers. In Run 2 the same procedures were done again, but this time using an TAP concentration of 3. 00 mm. During Run 3, 9. 00 mm of Nasal was dispensed in the left beaker and 10. 00 mm of Nasal was dispensed in the right.

TAP concentration was set to 1. Mm. I recorded data after each simulation run. Results Activity 2: Simulating Facilitated Diffusion When glucose carriers in the membrane were set to 500, the glucose transport rate for 2. 00 mm of glucose was . 008 ram/min. Equilibrium was reached at 43 minutes. At 700 glucose carriers the rate was . 0010 mm , and equilibrium was reached at 33 minutes. When the glucose carriers was set at 900 the rate was . 012 mm/min, and equilibrium was reached at 27 minutes. After changing the glucose concentration to 8. 0 mm, the glucose transport rate with 500 carrier proteins was . 023 mm/min, and equilibrium was reached at 58 minutes. With the simulation set at 700 carrier proteins the rate was . 0031 mm/min, and equilibrium was reached at 43 minutes. When the simulation was done with 900 carrier proteins the glucose transport rate was . 038, and equilibrium was reached at 35 minutes. Results Activity 4: Simulating Filtration With all solutes set at a concentration of 5. 00 MGM/ml and the MOOCOW set at 20, filtration stopped at 60 minutes, and the projected completion was 100 minutes. The residue analysis indicated all solutes present in the dialysis membrane.

The filtrate concentrations for all solutes was 0. 00 MGM/ml. With all solutes set tat concentration of 5. 00 MGM/m and the MOOCOW set at 50, the filtration completed in 40 minutes. The residue analysis indicated all solutes present in the dialysis membrane. The filtrate concentration for Nasal was 4. 1 MGM/ml, and 0. 00 MGM/ml for all remaining solutes. With all solutes set tat concentration of 5. 00 MGM/ml and the MOOCOW set at 100, the filtration completed in 20 minutes. The residue analysis indicated all solutes present in the dialysis membrane. The filtrate concentration for Nasal was 4. 1 MGM/ml, urea was 4. 74 MGM,’ml, glucose was 0. 00 MGM/ml, and powdered charcoal was 0. 00 MGM/ml. With all solutes set at a concentration of 5. 00 MGM/ml and the MOOCOW set at 200, the filtration completed in 10 minutes. The residue analysis indicated all solutes present in the dialysis membrane. The filtrate concentration for Nasal was 4. 4 MGM/ml, urea was 4. 74 MGM/ml, glucose was 4. 39 MGM/ml, and powdered charcoal was 0. 00 MGM/ml. Results Activity 5: Simulating Active Transport In this experiment the left beaker represented the interior of the cell and the right beaker represented the exterior.

With the addition of AT P, sodium was able to cross from the interior to the exterior using the sodium-potassium pumps. As TAP was increased from 1. 00 mm to 3. 00 mm, the rate of transport for both An+ and K+ increased. No transport took place when 9. 00 mm of Niacin was dispensed in the left beaker and 10. Mm of Nasal was dispensed in the right beaker. Discussion The purpose of the first experiment was to see how carrier proteins affect diffusion of the solute, glucose, across the membrane.

Glucose can not cross a membrane without assistance from carrier proteins because it is not lipid soluble and is also too large to pass through the membrane’s pores. Solute transport varied depending on the amount of carrier proteins available for the glucose. As seen in the experiment results, the rate of facilitated diffusion increased each time the number of protein carriers increased. Equilibrium was also achieved sooner as the number of protein carriers increased. The rate of diffusion slowed down when the concentration of glucose was increased, but the number of glucose carriers stayed the same.

For example at 500 glucose carriers, when the concentration of glucose was 2. Mm the rate was . 0008, and when the concentration of glucose was 8. Mm the glucose transport rate was . 0023. I noted that it took 43 minutes to reach equilibrium at a 2. Mm concentration, and it took 58 minutes to reach equilibrium at a 8. 00 ram concentration. The objective of Activity 4 was to observe how Nasal, urea, glucose, and powdered charcoal passed through a dialysis membrane. The membrane’s molecular weight cut off (MOOCOW) affected the rate of filtration.

As the membrane’s MOOCOW increased from 20 to 200, the rate of filtration increased as well. Excluding powdered charcoal, solute concentrations in the filtrate increased as the MOOCOW got larger. Filtration occurs because of pressure differences between the two beakers and the pore size of the dialysis membrane. This, for example, simulates the hydrostatic pressure difference from the interior and exterior of a cell and also pore size of cell membrane. The pressure in these simulations stayed set at 50 meg, but the MOOCOW changed. The larger the MOOCOW, the larger the poor size and the solute that could pass through the membrane.

During the 60 minute interval, all solutes failed to pass through the membrane when the MOOCOW was 20. Powdered charcoal was the only solute that could not filter through the dialysis membrane no matter the number of the molecular weight cutoff. This could indicate that powdered charcoal needed a higher pressure in order to pass through the membrane or a higher MOOCOW. Nasal was the solute that filtered the best through the membrane at a molecular weight cut off above 20. After each run the Membrane Residue Analysis was seed, and it detected solute residue in the membrane every time.

This indicated that there was solute substances that could not filter through the membrane to the lower beaker, instead the solutes remained in the dialysis membrane. In Activity 5, I experimented with the active transport of An+ and K+. I observed that more An+ and K+ moved better through the membrane when more TAP was dispensed. In the second run when 3. 00 mm of TAP was dispensed, all of K+ filtered from the right beaker into the left. This simulated that in the body all of K+ would have crossed from the exterior of the cell into the interior using the odium-potassium pumps.