The osmosis and tonicity of Plant and Animal cells …s3.amazonaws.com/prealliance_oneclass_sample/BMRXYo8Bnw.pdf · calculation to obtain delta weight is the final weight subtracted

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


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


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


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


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


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


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


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


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


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

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The osmosis and tonicity of Plant and Animal cells …s3.amazonaws.com/prealliance_oneclass_sample/BMRXYo8Bnw.pdf · calculation to obtain delta weight is the final weight subtracted