The osmosis and tonicity of Plant and Animal cells...
Transcript of The osmosis and tonicity of Plant and Animal cells...
The osmosis and tonicity of Plant and Animal cells
Joshua Fernandez
ID# 2051 5215
Mohanad Znbaqa
Vishaul Latchman and Aman Karblari
Section 010
BIOL 130L
Thursday
2:30pm-5:20pm
B2-Biology 2 149
November 7, 2013
Introduction:
The purpose of this lab is to demonstrate the movement of water in and out of a cell. Any
substances in random motion move from an area of high concentration to lower concentration.
This is known as diffusion. In biological systems, the movement of water through the cell
membrane is osmosis. There are three types of environments that the cell can be in. The first is
Isotonic. This is present when the concentration of solute in the cell cytoplasm and within the
cell is the same. Water will have no net movement because the concentrations are equal. The
second type is hypertonic. This is present when the concentration of the solutes in the cytoplasm
is higher than that of the cell. The net movement will be out towards the cytoplasm because there
is a higher concentration of water outside the cell than inside. Lastly there is hypotonic. This is
present when the concentration of solute is higher inside the cell than in the cytoplasm. The net
movement of water will be towards the inside of the cell because the concentration is higher
inside the cell than the cytoplasm. In all these cases, water moves from an area of low
concentration to an area of higher concentration in order to make the concentration even outside
the cell, as well as inside. For a plant cell and an animal cell, there are different terms that stand
for hypertonic, isotonic and hypotonic. In a plant cell, a hypotonic solution means it’s turgid, or
just normal. A hypertonic solution in a plant cell means its Plasmolyzed. Lastly, an isotonic
solution in a plant cell means its Flaccid. Turgid causes water to rush into the plant cell; however
it does not burst, for this is normal for the plant. Plasmolyzed causes water to rush out the plant,
causing it to shrink. This increases the salt levels in the plant. Flaccid is normal for plants, as
water enters and leaves the cell leaving it unchanged.
For animal cells, hypotonic solutions are known as lysed. Hypertonic solutions are known as
being shriveled. Isotonic solutions are known to be normal. Lysed means that water has rushed
into the cell to balance the concentration inside the cell. Normal means that water enters and
leaves so there is no net movement of water, ergo no change in the cell. Finally, shriveled means
that water has left the cell to balance the concentration in the cytoplasm of the cell, causing the
cell to become shriveled.
Materials and Methods:
“Refer to Biology 130 L Introductions to Cell Biology Lab Manual, BIOL 130L, Dr. Dragana
Miskovic, Department of Biology, fall 2013. pp. 43-47 (Department of Biology, University of
Waterloo, fall 2013). The experiment was performed without any deviation.”
Results:
Table 1: Beaker containing 200ml of distilled water and dialysis bag with 15ml distilled water
Time (minutes) Weight (grams) Delta Weight (∆ grams)
0 16.4 0
5 16.5 +0.1
10 16.7 +0.2
15 17.0 +0.3
20 16.8 -0.2
25 16.7 -0.1
30 16.4 -0.3
35 16.5 +0.2
40 16.8 +0.2
*The table above represents the results of the 15ml filled dialysis bag being submerged in 200ml
of distilled water. The positive signs show that of an increase in the weight, while the negative
signs show a decrease in weight. The delta sign represents a change in the weight with respects
to the previous trial. For example, for trials 5 minutes and 0 minutes. The change in weight is
16.4 to 16.5. The calculation to obtain delta weight is the final weight subtracted from the initial
weight. In this case, 16.5-16.4 equals +0.1, which means the weight has increased*
Table 2: Beaker containing 200ml of distilled water and dialysis bag with 15ml of 30% sucrose
solution
Time (minutes) Weight (grams) Delta Weight (∆ grams)
0 18.2 0
5 19.5 +1.3
10 20.1 +0.6
15 20.6 +0.5
20 21.1 +0.5
25 21.9 +0.8
30 22.4 +0.5
35 22.9 +0.5
40 23.5 +0.8
*The table above represents the results of the 15ml of a 30% sucrose solution filled dialysis bag
being submerged in 200ml of distilled water. The positive signs show that of an increase in the
weight. The delta sign represents a change in the weight with respects to the previous trial. For
example, for trials 5 minutes and 0 minutes. The change in weight is 18.2 to 19.5. The
calculation to obtain delta weight is the final weight subtracted from the initial weight. In this
case, 19.5-18.2 equals +1.3, which means the weight has increased*
Table 3: Beaker containing 200ml of distilled water and dialysis bag with 15ml of 60% sucrose
solution
Time (minutes) Weight (grams) Delta Weight (∆ grams)
0 19.2 0
5 20.3 +1.1
10 21.3 +1.0
15 22.5 +1.2
20 23.4 +0.9
25 24.1 +0.7
30 25.3 +1.2
35 26.5 +1.1
40 27.0 +0.5
*The table above represents the results of the 15ml of a 60% sucrose solution filled dialysis bag
being submerged in 200ml of distilled water. The positive signs show that of an increase in the
weight. The delta sign represents a change in the weight with respects to the previous trial. For
example, for trials 5 minutes and 0 minutes. The change in weight is 20.3 to 19.2. The
calculation to obtain delta weight is the final weight subtracted from the initial weight. In this
case, 20.3-19.2 equals +1.1, which means the weight has increased*
Table 4: Beaker containing 200ml of 60% sucrose solution and dialysis bag with 15ml of 30%
sucrose solution
Time (minutes) Weight (grams) Delta Weight (∆ grams)
0 20 0
5 18.6 -0.4
10 18.8 +0.2
15 18.5 -0.3
20 17.9 -0.6
25 17.7 -0.2
30 17.2 -0.5
35 16.9 -0.3
40 16.7 -0.2
*The table above represents the results of the 15ml of a 30% sucrose solution filled dialysis bag
being submerged in 200ml of 60% sucrose solution. The positive signs show that of an increase
in the weight. The delta sign represents a change in the weight with respects to the previous trial.
For example, for trials 5 minutes and 0 minutes. The change in weight is 18.6 to 20. The
calculation to obtain delta weight is the final weight subtracted from the initial weight. In this
case, 18.6-20 equals -0.4, which means the weight has decreased*
Table 5: Beaker containing 200ml of 60% sucrose solution and dialysis bag with 15ml of
distilled water
Time (minutes) Weight (grams) Delta Weight (∆ grams)
0 16.6 0
5 14.9 -1.7
10 14.7 -0.2
15 14.3 -0.4
20 12.4 -1.9
25 11.6 -0.8
30 10.5 -1.1
35 10.0 -0.5
40 9.3 -0.7
*The table above represents the results of the 15ml of a 30% sucrose solution filled dialysis bag
being submerged in 200ml of distilled water. The delta sign represents a change in the weight
with respects to the previous trial. For example, for trials 5 minutes and 0 minutes. The change in
weight is 16.6 to 14.9. The calculation to obtain delta weight is the final weight subtracted from
the initial weight. In this case, 14.9-16.6 equals -1.7, which means the weight has decreased*
*The above graph depicts the various dialysis bags named after their table and how their weight
changed after time increases. If the graph in going upwards, that is an increase in the weight,
while if the graph is going downwards, that is a decrease in weight*
*Drawings of Hematocrit animal cells and plant cells are attached to the lab report, they fall
under the results category*
Discussion:
The purpose of this lab was to demonstrate the various aspects of water movement in and out of
the cell. The first part of the lab was the use of dialysis bags that were placed in different
solutions. After being timed, the weight was checked to see if it increased or decreased. In the
first dialysis bag, a 15ml bag was place in 200ml of distilled water. The table for the most part
produced weights that were increasing. This is because the bag is in a hypertonic solution. This
means that the concentration water is higher outside the bag than inside. The water tries to
balance this by flowing into the bag, so that the weight outs. As the tonicity article states, “cells
survive in a hypertonic environment by increasing the transcription of genes whose products
catalyze cellular accumulation of water which helps to bring water into the cell” (Miyakawa,
Woo, Dahi, Handler, Kwon 1999). The next two bags were placed in 200ml of water as well, but
they contained 30% sucrose solution and 60% sucrose solution respectively. According to the
tables, their weight increased over the 40 minute time period as well. This is due to the fact that
the concentration of water is higher outside the cell than inside. Water always wants to flow from
an area of high concentration to low concentration in order to balance the levels on both sides of
the cell. For bags four and five, they were placed in 200ml of 60% sucrose solution. The table for
bag four showed that the bag decreased in weight over the period of forty minutes. This is due to
the fact that the bag is now in a hypotonic solution. Bag four contains a lower concentration of
solute, so that solute is going to want to leave the bag in order to balance the concentration
outside the bag. This results in the bag losing weight over that period of time.
The journal of metabolism and blood flow states that “In the presence of a hypotonic medium,
there was a rapid initial release followed by a much slower flow out of the cell with respects to
time” (Kimelberg, Rutledge, Goderie and Charniga 1995). The bag initially let out quite a bit of
solute, but then it started to slow down as the time increased. For bag five, the same thing
happened to it as well, only this time the bag was filled with water. As previously stated, water
flows from an area of high concentration to low concentration. The beaker contained only
sucrose, so the water flowed out in order to balance the concentration inside and outside the bag.
The second part of the lab was osmosis in animal cells. Three slides were viewed each
containing a hypertonic, hypotonic, or isotonic cell. The isotonic hematocrit was at 18%, and
when viewed, the cells were very close together, looking almost inseparable. This is due to the
fact that there is no net movement of water, so the cells are able to stay very close together. The
concentration of NaCl was only 0.14, so there was no need for the cells to move anywhere. The
second slide was the hypotonic hematocrit, at 1%. There were next to no cells present in this
slide because water rushed in to balance the concentration. The distilled water placed on the slide
is what rushed into the cell, causing almost nothing to be seen through the microscope. The last
slide was the hypertonic hematocrit at 14%. There were a couple of cells spread out throughout
the animal cell, but not very many. This is because this is a hypertonic solution. The
concentration of the NaCl was 0.34M, therefore causing the cells to rush out to the outside of the
cell in order to balance the concentration of the cell. The final part of the cell was osmosis in
plant cells. An onion slide was viewed through a microscope, and either NaCl or water was
dropped onto it.
For the Hypertonic slide, the cell appeared to be Plasmolyzed at some parts of the cells, but not
all. The vacuole was clearly visible and so was the cell wall. For plants, hypertonic is known as
Plasmolyzed. The plant loses a lot of water through the vacuole and ends up having pink regions
scattered around the cell. The second slide was that of an isotonic cell. What was seen here was
half of the cell being Plasmolyzed, while the other half is clear white. This is due to the fact that
there is no net water movement so the plant does not gain any water nor does it lose any. The last
slide was that of the hypotonic slide, or the turgid slide. Here, the whole cell was pink, and it was
very difficult to spot the vacuoles or the cell walls. This is because the hypotonic environment
doesn’t allow any extra water to enter into the cell via the vacuole. Ergo, the cell is full of water,
and the pink colour is what depicts that. The overall lab was a success as my findings match the
theory of osmosis and tonicity. My results show that the theories hold true, and that they are able
to give first hand examples of what happens under certain conditions. This lab explains to
students the importance of these environments, and how they affect the cells of both plants and
animals. Osmosis and tonicity and key topics as they further diverge into university topics such
as membrane transport and function. The overall lab was a success and was very interesting to
perform.
Cell Wall
Cell Wall
Cell Wall
Cell Wall
Cell Wall
Cell Wall
Cell Wall
Vacuole
Vacuole
Vacuole
Vacuole
Vacuole
Vacuole
Vacuole
Works Cited:
Kimelberg, Rutledge, Goderie and Charniga 1995. Tonicity-responsive enhancer binding protein,
a Rel-like protein that stimulates transcription in response to hypertonicity. Proc. Natl. Acad. Sci.
USA, Vol. 96, pp. 2538 –2542.
Miskovic 2013. Osmosis. BIOL 130 Cell Biology Laboratory Manual, pg 43-47
Miyakawa, Woo, Dahi, Handler, Kwon 1999. Astrocytic Swelling Due to Hypotonic or High K
Medium Causes Inhibition of Glutamate and Aspartate Uptake and Increases Their Release.
Journal of Cerebral Blood Flow & Metabolism 15, 409–416