DIFFUSION OSMOSIS REPORT.docx

University of Balamand

Faculty of Sciences

Department of Biology

General Biology 1 Laboratory

BIOL 22

!"periment #$ Di%usion &nd Osmosis

Date$ 11'11'21(

Submitted to$ )s* +amela )el,i

Submitted by$ Step-anie Da-r &1.11(

/ac-elle Diab &1(110 Introduction:

 The purpose of this experiment was to: - examine the principles of solute and water movement in both articial and living systems - observe diusion of a solid in a liquid - describe the eect of increased temperature on the movement of water molecules - examine diusion of solutes across a semi-permeable membrane - examine osmosis in living plant cells * lasma membrane: the plasma membrane is a semi-permeable membrane that separates the interior of the cell from the external environment and regulates the passage of substances !solute" and water# from the cell to the external environment" and vice-versa$% The plasma membrane is a bilayer that is made of proteins !integral and peripheral#" and lipids% * &ilayer: a bilayer is a layer of molecule which has ' hydrophobic tails facing the inner part of the molecule" and a hydrophilic head which faces the aqueous environment of the cell% In the plasma membrane" proteins of various (inds are distributed throughout the lipid bilayer% * )iusion: exchange of particles between the cell and the external environment through the semi-permeable membrane% imple diusion is when the particles !non- polar molecules# move from the area of high concentration to an area of low concentration% +lso" in diusion" molecules move down the concentration gradient% * ,smosis: the diusion of water through the semi-permeable membrane% * hen it comes to solute" there are three types of solutions: hypotonic! less than .%/0 of 1a2l#" hypertonic! more than .%/0 of 1a2l#" and isotonic!.%/0 of 1a2l#% -If placed in a: -3ypotonic: ater moves into the cell% -3ypertonic: ater moves outside the cell% -Isotonic : 1o net movement% * )ialysis: 4ovement of solute ! through water# through a selectively permeable membrane% )ialysis depends on the si5e and shape of the solute%

* 6ndocytosis: the phenomenon where the cells ta(es in large particles and ingests them% + type of endocytosis is phagocytosis% This is when a cell ta(es in and digest an ob7ect% * 4embrane carrier proteins: - 8acilitated diusion !down the gradient" from high to low concentration" and no energy required#% - rotein channels! passage of insoluble to lipid molecules through the membrane" no energy required# - +ctive transport! down and up the gradient" and require energy#" ex: sodium-potassium pump%

!"ercise #*1$ -e mec-anism of Di%usion: * In this exercise we are supposed to see the 7iggling of individual molecules%

 )aterials : - Toothpic( - )ropper bottle of water - 2armine dye powder - lide 9 2overslip - 2ompound 4icroscope * +rocedure$ - e obtained a clean slide and a coverslip '- e placed ' drops of water on the slide ;- Then" we used a toothpic( to remove a small amount of powder from the mother sample" and then we tapped the toothpic( on the slide !water part#% <- e placed the coverslip on top of the carmine dye lled water% =-Then" we placed the specimen on the stage of the microscope and we observed under low and high power ob7ectives%

 /esults and Discussion$

- ,n the low power ob7ective:

e were not able to see the particles of neither the water nor the carmine dye moving%

> ,n the high power ob7ective:

- e can obviously see that the carmine dye powder is insoluble in water !Tiny bits of the powder are suspended in the water% '-e were able to see the red granules vibrating or ? 7iggling?%

 This movement is called &rownian movement% This movement is due to the invisible particles of water that are vibrating" and colliding with each other and the red granules%

*ost @ab Auestions: - The carmine particles move randomly due to the bombardment of the particles by the Binvisible? water molecules% '- I cannot see the water molecules% 3owever" I can tell that they are moving% +s long as the temperature is above 5ero" the molecules are always on the move !constant motion#% ;- The movement of carmine particles is due to bombardment by water molecules% <- 6quilibrium is reached when the concentrations of the diusing substances are equal% The net movement of molecules will slow down as equilibrium is reached% =- The powder granules will stop moving at equilibrium% Thus" the net diusion will eventually come to an end%

C- + change in medium ! from water to gelatin# would cause the rate of diusion to slow down%

 !"ercise #*2 3 -e e%ect of emperature On Di%usion :  *In this experiment" we will see how the rate of diusion is aected by the temperature%

 )aterials$ -Two clean test tubes -Test tube rac( -+ dropper  

-8orceps -otassium permanganate -' mother solutions !  with hot water and the other with cold

water#%

 +rocedure$ - e obtained ' clean test tubes from a test tube rac( '-  lled about half the test tube with hot water and the other lled also about half the other test tube with cold water ! using a dropper#% ;- Dsing forceps" we both placed the same small amount of potassium permanganate ! powder# at the same time in the test tubes" and we observed the ndings%

 /esults$

In this picture" we can see that the potassium permanganate is mixed with the hot water better than with the cold water% In the hot water we almost have  color in all the tube" while in the cold water" the potassium permanganate is ta(ing more time to mix with all the regions of the water in the tube%  Therefore" we can conclude that when the temperature augments" the rate of diusion augments%

* ost-@ab Auestions: E- +fter three minutes" the diusion in the tube with hot water is the greatest% F- The temperature of the tube with greatest diusion increases the molecular motion of the water and potassium permanganate% /- Ges" the tube with least diusion will eventually reach the same state as the tube with greatest diusion because the temperature only ma(es the rate of diusion faster%

* !"periment #*( 3 Osmosis$ 4Involves only 5ater di%usion6 * we chose potato for this experiment because it gives the fastest results% * In this experiment we are supposed to see a change in the si5e and shape of the potato cylinders%

 )aterials : - half a cut potato !to get / potato cylinders# - '.0 1a2l solution ! hypertonic# - .%/0 1a2l solution ! isotonic# - )istilled water !less than .%/0 1a2lH hypotonic# - 8orceps - uler - aper towels - 2or( &orer - &alance - etri dishes !with their cover#

+rocedure$

- e cut / potato cylinders using the ?2or( &orer? and placed them on a etri dish cover% Then" we evened them out using the (nife and a ruler% '- e too( the measurements of each potato cylinder ! using a ruler# and recorded them% Then" we too( the cylinders to the balance and measured each cylinderJs weigh and recorded them% ;- e too( ; petri dishes and lled each one of them with a solution ! hypotonic" hypertonic" and isotonic#" and we labeled them% <- Then we placed ; potato cylinders in each of the ; petri dishes and labeled their places% =-e waited '. minutes for them to equilibrate% C- +fter '. minutes of waiting" we threw away the solutions and we wiped the cylinders with a paper towel" then" we too( the weigh and length of each one of them and recorded them%

/esults and Discussion olution

@ength !cm# &efore +fter

'.0 1a2l !hyperton ic# .%/0 1a2l !Isotonic# )istilled ater !3ypotoni c#

eight !g# &efore .%C' .%C ; CF .%C. CE .%C ;;

.%=/ FC

+fter .%C ./

.%=C /F

.%=/ '/

.%=; =<

.%=/ <

.%C;
.%C. FE

.%CE =<

.%C' '/

.%=/ E=

.%CF E

.%E ';

.%CF ./

ost-@ab Auestions ;# changes in length of the potato cylinders are due to the moving of water molecules into and out of the cell by osmosis" although each molecule moves randomly" the water molecules as a whole move in the net direction of into or out of the cell <# '.0 1a2l solution was hypertonic =#in the isotonic solution there would be no net movement of the water molecules because the solute concentration on the inside of the potato is the same as that on the outside of the potato !.%/0 1a2l#

C# distilled water E# In ten percent 1a2l the red blood cell will shrin( and shrivel away because water would leave the red blood and move out to the !hypertonic# lower concentration of water area" however" in distilled water" !hypotonic# the red blood cell will swell and eventually burst because water molecules have a net movement into the cell F# water will move out of tube +" water will have no net movement in tube b" and water will move into tube 2" this is because

!"periment #*. 3 )embrane +ermeability )aterials: K

three test tubes

K

test tube rac(

K

boiling water bath at C. degrees celcius

K

dialysis tube

K

paralm

K

starch solution

K

glucose solution

K

benedicts reagent

K

iodine solution

K

droppers

met-ods$ #

rst we obtained a test tube and lled it half way up with water

'# then we obtained a strip of dialysis tubing and we tied a (not at one of the ends of the dialysis tube" then pulled on the (not a little bit to ma(e sure that it was water tight" ;# we then opened the other end of the dialysis tube and" using the dropper" we lled half of the dialysis tube with starch solution and the" using a dierent dropper other half with glucose solution

<# we then closed the dialysis tubing and bent the closed part of the dialysis tubing over the edge of the tubing =# we rinsed the dialysis tube and then we put the dialysis tube into the test tube that was half lled with water" and then we bent the top of the dialysis tube over the edge of the test tube and applied paralm to the test tube and securely wrapped and twisted the dialysis tube around the test tube and secured it in the test tube C#

we then lled up the rest of the test tube with distilled water

E#

we waited '. minutes at for what we thought was diusion to occur

F# remove the paralm and ta(e out the dialysis tubing and separate the liquid in the dialysis tube into two separate test tubes using a dropper /#

label the rst test tube one and the other test tube '

.# do the same thing with the water" divide the liquid into two test tubes and label the rst one one" and the second one second" # test the number one solutions against benedicts reagent" by adding benedicts reagent and putting the test tube into a water bath at C. degrees celsius for . minutes '# test the number two test tubes with iodine solution !test for the presence of starch# ;#

record observations and results

+ost7lab 8uestions .# yes the glucose diused out of the tubing " because the result for the liquid in the test tube when tested against benedicts reagent we got a mustard yellow precipitate # no the starch did not diuse out of the test tube because the result for the number two test tube gave a yellow solution on addition of iodine solution '# glucose molecules are smaller than starch molecules" which ma(es sense because starch is a polymer of glucose -

e"periment #*#7 plasmolysis in a green plant leaf materials$ K

live plant leaf  

K

compound light microscope

K

'.0nacl solution

K

the percentage of salt solution in the body cells is .%/0

)et-ods # the microscope was prepared and all we had to do was observed

/esults and Discussion

+ost Lab 9uestions /# water leaves the plant by process of osmosis" which is the movement of water molecules from an area of high water concentration to an area of low water concentration '.#the '.0 salt solution is hypotonic to the solute concentration of the leaf cells '# put the leaf in a solution that has a lower !hypertonic# solute potential to it and a higher water potential to it" so that the net movement of water molecules is into the cell ''# in normal plant cells the chloroplasts can be found towards the edges of the leaf" theyLre pushed there by the turgidity of the vacuole however" in a salt treated plant leaf the chloroplasts would have been pulled away from the edges of the cell near the plasma membrane