Polytechnic University of the Philippines College of Social Sciences and Development Department of Psychology
BIOLOGICAL MEMBRANES (DIALYSIS, OSMOSIS AND DIFFUSION)
Submitted by:
SAN MIGUEL, Djanelle Mei M. DELOS REYES, Erica Gabrielle MORAL, Chatlette Karl COLAMBO, Mark John Peter GO, Thea CABIGAO, Jereme Anne
Submitted to:
Prof. Cris Argamino
BS PSYCHOLOGY 3-4
Abstract
This laboratory experiment is meant to be done for the students to be able to understand and find the similarities and differences of Dialysis, Osmosis and Diffusion in Biological Membranes and how they relate and and connect to each other. other.
This
experiment will show the relationship of temperature and concentration in molecular level and through biological membranes. The main objective of performing the experiment is to show the effects of concentration and temperature on diffusion and osmosis. This experiment will help us know the importance of diffusion and osmosis to cells particularly to animal and plant cells. KEYWORDS: 1) Dialysis, 2) Osmosis, 3) Diffusion, 4) Biological membranes, 5)
Temperature and concentration, 6)Molecular level, 7) Animal and plant cells
Introduction
All cells are all like living organisms inside our bodies. They are the one that is responsible to the things happening inside and outside of the body. Just like us, cells have a protection. All cells are enclosed with a cell membrane. Each cell membrane in each cells have a function. A cell membrane is like a barrier that allows the passage of a liquid or substance to enter or leave a cell. Diffusion, osmosis and dialysis, as we all know are widely known concepts in both Biology and Chemistry. These concepts are widely represented in many books in many ways to be able to help students analyze and understand how it works, especially at molecular levels. In order to explore and familiarize these concepts, we performed an experiment to end up with conclusions relevant to the main objective of the experiment which is to show effects of concentration and temperature on diffusion and osmosis There are processes in which how the cell membrane allows the passage of a substance in the cell – the diffusion, osmosis and dialysis. Osmosis is the process that causes a liquid (especially water) to pass through the wall of a living cell (MerriamWebster, 2016). Diffusion refers to the process by which molecules intermingle as a result of their kinetic energy of random motion (BBC, 2014). The researchers learn how cell membrane functions in different ways. The researcher conducted an experiment which allows knowing how diffusion, osmosis and dialysis work within a cell. This experiment also showed types of passive transport namely, diffusion and osmosis. The experiment will show the movements of molecules. It also shows us how the hypertonic,
isotonic and hypotonic solutions reacted when isotonic saline solution, hypotonic salt solution and hypertonic salt solution reacted to red blood cells.
Methodology 1. Diffusion 1.1.
Diffusion of solutes in water A dot of KMnO4 “
Place in each test tubes
Distilled Water
1.2.
Tap Water
”
Hot Distilled Water
Cold Distilled Water
Test tube 3
Test tube 4
Diffusion in a colloid
Melt gelatine
Test tube 1
Test tube 2
Allow to cool
Add ~0.5ml of KMnO4, Methylene Blue and Congo Red
Measure the migration of the dye starting at the top-level of the gelatine for 120mins.
Repeat procedure for set 2
2. Osmosis 2.1.
Osmosis (Longganisa Casting Model)
Make a solution of ~10ml sugar and water
Obtain the weight of the test tube at 10-mins interval for 60-mins.
Repeat procedure for set 2
2.2.
Place on a test tube
Cover the mouth of the test tube with 1-ply of Langgonisa casing and secure it with rubber band.
Weigh
Suspend the test tube upside down in a 250ml beaker containing water. Use iron clamp to hold the test tube.
Osmosis in RBC Slide 1
Drop blood in each slides
Slide 2
Slide 3
Apply a drop of Hypotonic Solution (0.30 M NaCl) Apply a drop of Hypertonic Solution 3.0M NaCl Apply a drop of Isotonic-Normal Solution (0.85M NaCl)
Observe under microscope
3. Dialysis
Fill test tube with 3ml Methylene Blue and 5ml Saturated CaCl2 Solution
Cover the mouth of the test tube with 1-ply of Langgonisa casing and secure it with rubber band.
Tabulate the results
Suspend the test tube upside down in a 250ml beaker containing water. Use iron clamp to hold the test tube.
Test the presence of Methylene Blue, Chloride and and Calcium in the beaker after every minute in 30-mins.
The experiment was divided into 3 parts. First diffusion and is divided into two sub-parts; diffusion of solutes in water and diffusion in a colloid. The second one, osmosis and was also divided into two sub-parts; osmosis ( longganisa casing model) and osmosis in red blood cell (RBC) . The last part is, dialysis. The first process is, Diffusion. A series of test tubes containing distilled water, tap water, hot distilled water (70 °C or higher) and cold distilled water on ice were separately prepared. The test tubes were labelled accordingly. After labelling, a “dot” amount of potassium permanganate (KMnO4) crystals were placed to each test tubes and took note of the time at which the KMnO4 crystals were completely dissolved in the water. The second process is diffusion in colloid. In the experiment of diffusion of colloid, the gelatin was melted according to the manufacturer’s procedure. Next, prepare 8-10 test tubes and pour the gelatin mixture to each test tube and allow it to solidify. Two sets of gelatin were made. After the gelatin was completely hardened,
overlay 0.05 ml of the potassium permanganate, Congo red and Methylene blue in each test tube. Finally, measure the migration of the dye starting at the top level of the gelatin using the ruler and record the measurements for 60 minutes at 10 minutes intervals or until the dye reaches the bottom. For the first process of osmosis, which is the longganisa casing model, the first thing to do is to place 10 mL of saturated sugar solution in a test tube. Next, cover the mouth of the test tube with 1-ply of longganisa skin and secure it with a rubber band. After securing the cover of the test tube, use a triple beam balance to acquire the weight of the covered test tube. Next, suspend the test tube upside down in a 250 mL beaker containing distilled water and use iron clamp to fasten the test tube. Lastly, obtain the weight of the test tube at 10-minute intervals for 60 minutes and tabulate the data and observations. The second process in osmosis is observed by the presence of RBC. The first step is to prepare three clean glass slides and cover slips with a drop of blood on each glass slides. You can use sterile lancets to prick a donor’s finger to be able to get
samples of RBC. After that, apply drop of Isotonic- Normal Saline Solution (0.85 M NaCl) in one glass slide, a drop of hypertonic salt solution (3.00 M NaCl) in another glass slide and hypotonic salt solution (0.30 M NaCl) to the remaining glass slide. To be able to end up with a conclusion, observe the appearance and sizes of the RBCs under the microscope. The last part of the experiment is dialysis. The first step in this experiment is to fill a test tube with 3 mL Methylene blue solution and 5 mL saturated CaCl2 solution. Cover
the test tube with 1-ply of longganisa casing and secure it with a rubber band. After that, suspend the test tube upside down in a 250 mL beaker containing distilled water and use an iron clamp to fasten it. The main objective of this experiment is to test the presence of Methylene blue, chloride and calcium. We can test this by taking a sample of beaker-water for 30 minutes in two minutes interval. Lastly, tabulate the results and observations.
Results 1. Diffusion 1.1.
Diffusion of Solutes in Water TABLE 1. Time consumed to dissolve Potassium Permanganate Time where KMnO 4 completely dissolved in
Ranking
water
Distilled Water
1 hour and 10 minutes
Third
Tap Water
1 hour and 16 minutes
Fourth
Hot Distilled Water
40 minutes
First
Cold Distilled Water
50 minutes
Second
Table 1 shows how much time the four waters dissolved KMnO 4. The hot distilled water dissolved KMnO 4 in about 40 minutes which is the fastest among the four. While, tap water has the longest time to dissolve the substance in 1 hour and 16 minutes. 1.2.
Diffusion in a Colloid TABLE 2. SET A: Migration of the three substance in a gelatin
Chemical
10min
10min
10min
10min
10min
10min
10min
10min
10min
10min
s
s
s
s
s
s
s
s
s
s
s
KMnO 4
0.5cm
0.5cm
0.6cm
0.6cm
NC
0.6cm
NC
NC
0.6cm
NC
Congo
0.5cm
0.5cm
0.8cm
0.9cm
1.0cm
NC
NC
1.3cm
NC
1.4cm
0.5cm
0.5cm
NC
NC
NC
0.6cm
NC
NC
0.7cm
NC
Red Methylen e Blue *Note: NC means no change. TABLE 3. SET B: Migration of the three substance in a gelatin Chemical
10min
10min
10min
10min
10min
10min
10min
10min
10min
10min
s
s
s
s
s
s
s
s
s
s
s
KMnO 4
0.5cm
NC
0.6cm
0.6cm
NC
0.6cm
NC
NC
0.6cm
NC
Congo
0.5cm
NC
0.8cm
0.9cm
1.0cm
NC
NC
1.3cm
NC
1.4cm
0.5cm
NC
NC
NC
NC
0.6cm
NC
NC
0.7cm
NC
Red Methylen e Blue *Note: NC means no change.
In the two tabulated results for Set A and B (Table 2 and 3), all three chemical migrated in the colloid. Congo red migrated the largest amount of 1.4 cm for both Set A and B, while, KMnO 4 shows the least migration in all three chemicals with only 0.6 cm in both Set A and B. 2. Osmosis 2.1.
Osmosis (Longganisa Casing Model)
TABLE 4. Decrease of weight of the Langgonisa Casing Model Set A
Set B
Starting Weight
41.2 g
30.0 g
10 mins
41.9 g
30.4 g
20 minutes
41.5 g
30.1 g
30 minutes
39.1 g
29.9 g
40 minutes
38.8 g
29.3 g
50 minutes
36.4 g
28.9 g
60 minutes
35.9 g
28.2 g
For about 60 minutes, the researchers obtained the weight of each set- ups every 10 minutes. The tabulated data, Table 4, shows that the weight of the set-up decreases in every 10 minute intervals. This shows that in every 10 minutes, the sugar solution inside the test tube decreases. 2.2.
Osmosis in RBC
FIGURE 1 RBC with Hypertonic Salt Solution
FIGURE 2. RBC with Hypotonic Salt Solution
FIGURE 3. RBC with Normal-Saline Solution
The Hypertonic salt solution turned the RBC to steadily increase its pressure and size that made it more visible than the RBC with Hypertonic salt solution. However, the RBC with a drop of normal-saline solution retains its normal size. 3. Dialysis TABLE 5. Changes in the water every minute Time
Oxalic Acid
Silver Nitrate
Methylene Blue
There’s a change in color in the first try. Two minutes
The water in the test tube became slightly blurry white.
Four minutes
The color of blurry white still continues The water in the
Six minutes to darken.
beaker is still clear.
No reaction There are tiny precipitates that can be seen in the Eight minutes
mixture and the blurry white color became more obvious.
10 minutes
As the time goes
A touch of color bue
on, the blurry white
can be seen on the
color became
water in the beaker
darker and the
but in a slightly
precipitate became
manner.
more obvious.
12 minutes Little formation of moist in the test 14 minutes
tube wall and a mild change in temperature As the time goes The moist formed on, the color of the
16 minutes
more in the wall of Methelyne Blue the test tube became more The moist become obvious in the water more obvious in the beaker. It compared to the grows darker and
18 minutes
earlier minutes and darker. the temperature continue to grow colder The temperature
20 minutes
started to decrease and become colder
and the moist is still growing more in the test tube glass 22 minutes
As the time goes
24 minutes
on, the temperature
26 minutes
in the test tube decreases that it grows colder and
28 minutes the moist is become more noticeable The precipitate The moist in the test formed became tube became more more obvious that it
The color blue in the
floats in the mixture.
water became
The blurry white
darker than the
color is at its higher
earlier minutes.
noticeable that it 30 minutes
almost made the glass blurry. The temperature compare to the remains cold. earlier colors.
The tabulated results in Table 5 show the time where each mixture made their reaction. This clearly displays that Silver Nitrate pass through the longganisa casing first in two minutes, while Oxalic Acid is the last mixture that shows reaction within 14 minutes.
Discussion 1. Diffusion 1.1.
Diffusion of Solutes in Water
The experiment anticipates knowing of the four temperatures or kinds of water can dissolve KMnO 4 faster. The tap water, distilled water, hot distilled water and cold distilled water act as a solvent in which they have to dissolve Potassium Manganate (KMnO 4). In the set-up, there are four test tubes that are placed in the test tube rack. Each test tube contains the same amount of four water solutions. The researchers drop a small amount of KMnO4 in each test tube. 1.2.
Diffusion in a Colloid
The experiment is expecting to learn which chemical will make a larger migration in a colloid by using KMnO 4, Methylene blue and Congo Red. Colloids are substance that consists of particles dispersed throughout another substance which are too small (Merriam-Webster, 2016). In this experiment, the researchers used a gelatin to form a colloid. The researchers drop an approximately 0.5ml of each chemical in each of the 3 test tubes. In the two tabulated results for Set A and B (Table 2 and 3), all three chemical migrates in the colloid. Congo red migrates the largest amount of 1.4cm for both Set A and B, while KMnO 4 shows the least migration in all three chemicals with only 0.6cm in both Set A and B.
2. Osmosis 2.1.
Osmosis (Longganisa Casing Model)
This experiment aims to know the weight of the test tube set- ups with sugar solution and a longganisa casing as it covers for every 10 minutes in 60 minutes. The role of the longganisa casing is to act as a semi-permeable membrane that limits the passage of water in each container – test tube and beaker. There are two pressures that can be found in this set-up, one that is coming from the test tube and the other that is coming from the water in the beaker. 2.2.
Osmosis in RBC
In this experiment, the researchers are assigned to define which red blood cell can be formed the largest when being dropped by Hypotonic Salt Solution, Hypertonic Salt Solution and Normal-Saline Salt Solution.
The Hypertonic Salt Solution concentration of water is higher within the cell. There is a net movement of water from inside to outside of the cell. Water leaves the cell by osmosis which causes the cell to shrink as its internal pressure decreases. Hypotonic Salt Solution contains higher concentration of water and lower concentration of solutes. Since, the concentration of water is higher outside the cell. There is a net movement of water from outside into the cell. Cell gains water, swells and the internal pressure increases. Eventually burst (Haemolysis). While, isotonic solution is a solution in which the concentrations of solutes are equal, so: first, water diffuses in and out of the cell at equal rates; second, here is no net movement of water across the plasma membrane; third, the cells retain their normal shape.
The Hypertonic salt solution turned the RBC to steadily increase its pressure and size that made it more visible than the RBC with Hypertonic salt solution. However, the RBC with a drop of Normal-Saline Solution retains its normal size. 3. Dialysis
The experiment expects to know which of the three chemical (Oxalic Acid, Silver Nitrate and mixture of Methylene Blue and Saturated CaCl 2) will pass through the longganisa casing first. Longganisa casing acts as a semi-permeable membrane – a barrier that allows
some molecules to move through it, where in others cannot. In the set-up that is used where the test tube is being suspended in the water inside the beaker while it is positioned upside-down, there are two pressures acting – the pressure inside the test tube and the one in the beaker, which controls the exchange of mixture inside and out of the test tube. The mixture of Methylene blue and Saturated CaCl
2
is passing through
the longganisa casing which affects the water in the beaker that it turns into blue. While doing the experiment, the researchers made two sets of test tubes, one test tube is for the Oxalic Acid and the other one is for the Silver Nitrate. In every two minutes in 30 minutes, the researchers gathered small amounts of water in the beaker and pour it into each of the test tubes. The researchers continued this process for 30 minutes.
Conclusion
To sum up, temperature, concentration gradient and molecular weights affect the diffusion which is the movement of molecules from a region of higher concentration to lower concentration. These transport processes got through the process of diffusion across membranes which are semi-permeable allowing certain molecules to pass through, regulating the entry and exit of molecules inside and outside the cell. Temperature and concentration gradient varies directly to the rate of diffusion. As the concentration gradient and temperature increases the rate diffusion will also increase. On the other hand the molecular weight is inversely proportional to the rate of diffusion.
Reference BBC. (2014). “Diffusion”. BBC-GCSE Bitesize: Diffusion. BBC Teachers, 2014.
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/cells/cells
3.shtml
Beltran, Agapito J., et al. (2005). Biology 22: General Zoology Laboratory Manual (Third Edition). Blamire, John. (1999). Osmosis: Brother Gregory Investigates. http://www.brooklyn.curry.edu/bc/ahp/ChemInvest/CI.Q2.html . Merriam-Webster Dictionary. (2016). Colloid. Merriam-Webster Dictionary. (2016). Hypertonic. Merriam-Webster Dictionary. (2016). Hypotonic. Merriam-Webster Dictionary. (2016). Isotonic. Merriam-Webster Dictionary. (2016). Osmosis. Verma, Rituraj. (2016). “What is the difference between diffusion and osmosis?”.
https://www.quora.com/What-is-the-difference-between-diffusion-and-osmosis
