Membrane Transport Lab Report
1 Experiment
Membrane Transport
Objectives ► Referring to energy, what two ways can substances enter a cell?
What is active transport? What is passive transport? How is osmosis related to diffusion? How can we demonstrate active transport? How can we demonstrate Brownian movement? How can we demonstrate diffusion (2 ways)? How can we demonstrate osmosis (3 ways)? In terms of relationships between substances, how can we define “hypertonic”, “isotonic”, and “hypotonic”? What is the relationship between the size of a molecule and its rate of diffusion?
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Supplies ► Materials Needed
Active Transport: Baker’s Yeast 0.75% Na2CO3 0.02% Neutral Red Erlenmeyer Flasks …show more content…
Make 3 sugar solutions, one 40%, and one 10%. Set up 5 artificial cells. Into cell #1 put some of the 40% solution, into cell #2 the 20% solution, into cell #3 the 10% solution, and into cell #4 and cell #5 put distilled water. 3. Take the 5 beakers. Into beaker #1 and #2 put distilled water, into #3 put 10% sugar, into #4 put 20% sugar, and into #5 put 40% sugar. Weigh each artificial cell and place it into its corresponding beaker. 4. At the end of the laboratory period—or later in the day, depending in the directions from your instructor—remove the cells from the beakers, wipe the cells with a paper towel, and reweigh. Calculate the percent differences in weight for each cell. Chart you results on Table2. What type of differences do you see in the different cells? How would you explain these …show more content…
In flask #2 the neutral red must have been transported into the living yeast cell. In Flask #1 the yeast cells were killed so no transport could occur. These pumps correspond to the sodium/potassium pump in the cell membrane. The sodium/potassium pump actively pumps three sodium ions out of the cell for every two potassium ions pumped into the cell, thus maintaining the membrane potential. You may wish to figure out other macroscopic situations where active energy input is required. The potassium permanganate should have traveled about twice as far as the potassium chromate. The potassium chromate should have traveled just a bit further than the methylene blue. Water will continue to enter the thistle tube containing the sugar. Eventually (perhaps not until the next day) the sugar water may spill out the top of the tube because equilibrium is never reached. The sugar molecule is too large too pass through the membrane so the water in the beaker will remain pure. Water will enter the salt thistle tube and you will note an initial rise in the water lever, perhaps reaching half way up the tube. Then the water level will
Membrane Transport
Objectives ► Referring to energy, what two ways can substances enter a cell?
What is active transport? What is passive transport? How is osmosis related to diffusion? How can we demonstrate active transport? How can we demonstrate Brownian movement? How can we demonstrate diffusion (2 ways)? How can we demonstrate osmosis (3 ways)? In terms of relationships between substances, how can we define “hypertonic”, “isotonic”, and “hypotonic”? What is the relationship between the size of a molecule and its rate of diffusion?
____________________________________________________________________________
Supplies ► Materials Needed
Active Transport: Baker’s Yeast 0.75% Na2CO3 0.02% Neutral Red Erlenmeyer Flasks …show more content…
Make 3 sugar solutions, one 40%, and one 10%. Set up 5 artificial cells. Into cell #1 put some of the 40% solution, into cell #2 the 20% solution, into cell #3 the 10% solution, and into cell #4 and cell #5 put distilled water. 3. Take the 5 beakers. Into beaker #1 and #2 put distilled water, into #3 put 10% sugar, into #4 put 20% sugar, and into #5 put 40% sugar. Weigh each artificial cell and place it into its corresponding beaker. 4. At the end of the laboratory period—or later in the day, depending in the directions from your instructor—remove the cells from the beakers, wipe the cells with a paper towel, and reweigh. Calculate the percent differences in weight for each cell. Chart you results on Table2. What type of differences do you see in the different cells? How would you explain these …show more content…
In flask #2 the neutral red must have been transported into the living yeast cell. In Flask #1 the yeast cells were killed so no transport could occur. These pumps correspond to the sodium/potassium pump in the cell membrane. The sodium/potassium pump actively pumps three sodium ions out of the cell for every two potassium ions pumped into the cell, thus maintaining the membrane potential. You may wish to figure out other macroscopic situations where active energy input is required. The potassium permanganate should have traveled about twice as far as the potassium chromate. The potassium chromate should have traveled just a bit further than the methylene blue. Water will continue to enter the thistle tube containing the sugar. Eventually (perhaps not until the next day) the sugar water may spill out the top of the tube because equilibrium is never reached. The sugar molecule is too large too pass through the membrane so the water in the beaker will remain pure. Water will enter the salt thistle tube and you will note an initial rise in the water lever, perhaps reaching half way up the tube. Then the water level will