Download - Bio22Lab Exer4 PartE

Part E. Osmosis in Red Blood Cell

Exercise 4: Cell Transport

Introduction

Osmosis is the diffusion of free water across a

selective permeable membrane. Living cells react to

changes in the solute concentration of their environment

depends whether or not they have cell walls. Human red

blood cells can tolerate neither excessive uptake nor

excessive loss of water.

Osmosis manifest itself in many interesting

application. Biochemists use hemolysis to study blood

contents. Another example is the use of hemodialysis, in

which blood is removed and pumped into a machine that

filters the toxic substance out of the blood, by passing it

through an artificial porous membrane.

Introduction

Objectives

At the end of the exercise the student should be able to:

1. Compare and contrast the different types of tonicity and describe each effect on the cell.

2. Describe the relationship between concentration and the transport of molecules in a cell.

3. Discuss the importance of the concept in the applications in the health sciences.

Hypothesis

1. Cells immersed with the 0.07 M solution are the biggest, followed by the 0.15 M solution and lastly the 0.30 M solution

2. Cells immersed with the 0.07 M solution were the smallest, followed by the 0.15 M solution and lastly the 0.30 M solution

Significance of the Study

Osmosis manifest itself in many interesting applications. For example, in the field of health sciences, one must know the concept of osmosis in treating hemolysis and the treatment hemodyalisis.

Hemolysis is the destruction of the RBCs which leads to the release of hemoglobin from within the RBCs into the blood plasma.

Significance of the Study

In hemodialysis, a machine filters wastes, salts and fluid from your blood when your kidneys are no longer healthy enough to do this work adequately. Hemodialysis is the most common way to treat advanced kidney failure.

3 CLEAN MICROSCOPE

SLIDES LABELED AS A, B, & C

EXTRACT 3 DROPLETS OF

BLOOD W/ A STERILE LANCET

SLIDE A:DROP OF BLOOD +

0.07 M NaCl

SLIDE B:DROP OF BLOOD +

0.15 M NaCl

PLACE THE SLIDES INTO 3 SEPARATE

MICROSCOPES

SLIDE C:DROP OF BLOOD +

0.30 M NaCl

Methodology

MIX THE BLOOD AND SOLUTION THOROUGHLY

SMEAR THE MIXTURE EVENLY ON THE SURFACE OF THE SLIDES

FOCUS THE SLIDES AT 400X AND MEASURE THE DIAMETER OF THE CELLS EVERY 5 MINUTES FOR ABOUT

AN HOUR(NOTE: YOU MAY USE AN OCULAR MICROMETER)

OBSERVE FOR CHANGES IN THE SHAPE OF THE CELLS IN EACH SLIDE

ResultsNaCl Concentrations

(M) Cell No. & Size (µm)

TimeAverage µm at 30

minutes5 10 15 20 25 30

0.07

Cell 1 7.2 14.4 10.8 10.8 7.2 10.8

8.4Cell 2 10.8 10.8 10.8 10.8 10.8 7.2

Cell 3 10.8 10.8 10.8 10.8 7.2 7.2

0.15

Cell 1 10.8 10.8 10.8 10.8 10.8 10.8

10.8Cell 2 10.8 7.2 10.8 14.4 10.8 10.8

Cell 3 10.8 10.8 10.8 10.8 10.8 10.8

0.3

Cell 1 10.8 14.4 10.8 10.8 14.4 10.8

9.6Cell 2 10.8 10.8 14.4 7.2 14.4 10.8

Cell 3 10.8 14.4 14.4 10.8 14.4 7.2

Discussion

• On 0.07 M NaCl, - On the 10-15 minute mark, there is a slight increase in the size of the cells. At 30-minute time mark some cells started to burst while others swell.

Discussion

• On 0.15 M NaCl, - There is no distinct change in the size of the RBCs, as well as the shape during the first half of the observation. After 30 minutes observation, there is still no particular change in size and shape.

Discussion

• On 0.30M NaCl,– For the first 5 minutes, there are already

noticeable changes on the RBCs that could be observed. The RBCs are freely flowing under the microscope while they were measured. A slight crumpling appearance of the RBCs were noted. As time went on, the RBCs continued to crumple.

Discussion

1. ISOTONIC • An isotonic solution refers to two solutions

having the same osmotic pressure across a semipermeable membrane. This state allows for the free movement of water across the membrane without changing the concentration of solutes on either side.

• When cells are in isotonic solution, movement of water out of the cell is exactly balanced by movement of water into the cell. A 0.9% solution of NaCl (saline) is isotonic to animal cells. When exposing animal tissues to solutions, it is common to use an isotonic solution such as Ringer's buffered saline so as to prevent osmotic effects and consequent damage to cells.

Discussion

2. HYPOTONIC • A hypotonic solution is any solution that has a

lower osmotic pressure than another solution. In the biological fields, this generally refers to a solution that has less solute and more water than another solution.

Discussion

Discussion

• If concentrations of dissolved solutes are less outside the cell than inside, the concentration of water outside is correspondingly greater. When a cell is exposed to such hypotonic conditions, there is net water movement into the cell. Cells without walls will swell and may burst (lyse) if excess water is not removed from the cell. Cells with walls often benefit from the turgor pressure that develops in hypotonic environments.

Discussion

3. HEMOLYSIS• Hemolysis is the breakdown of red blood

cells.

Discussion

4. HYPERTONIC• In a hypertonic solution the total molar

concentration of all dissolved solute particles is greater than that of another solution, or greater than the concentration in a cell.

Discussion

• If concentrations of dissolved solutes are greater outside the cell, the concentration of water outside is correspondingly lower. As a result, water inside the cell will flow outwards to attain equilibrium, causing the cell to shrink. As cells lose water, they lose the ability to function or divide.

Discussion

5. CRENATION• The notched appearance of an erythrocyte

due to its shrinkage after suspension in a hypertonic solution

Conclusion

• From the result of the experiment, we can therefore conclude that the 0.07M solution has the biggest RBCS throughout the 30-minute period. The RBCs under 0.15M NaCl retained there sizes while the RBCs under 0.30M NaCL shrank.

Conclusion

• From the result of the experiment we conclude that: – RBC exposed to 0.07 M increase in size since the

solution is hypotonic – RBC exposed to 0.15 M almost did not change,

therefore the solution is isotonic – RBC exposed to 0.30 shrunk since the solution is

hypertonic

Recommendations

• A better high powered microscope to be used in observing and measuring RBCs

• More red blood cells to be observed and measured.

The researchers recommend the following:

Reference

• http://www.phschool.com/science/biology_place/biocoach/biomembrane1/hypertonic.html

• http://www.phschool.com/science/biology_place/biocoach/biomembrane1/hypotonic.html

• http://www.phschool.com/science/biology_place/biocoach/biomembrane1/isotonic.html

• http://www.mayoclinic.org/tests-procedures/hemodialysis/basics/definition/prc-20015015

• https://prezi.com/q3hx_zm0xegn/osmosis-in-red-blood-cell/• http://www.medicinenet.com/script/main/art.asp?

articlekey=3694

Reference

• http://study.com/academy/lesson/hypotonic-solution-definition-example-diagram.html

• http://study.com/academy/lesson/isotonic-solution-definition-example-quiz.html

• http://www.biology-online.org/dictionary/Crenation• https://www.nlm.nih.gov/medlineplus/ency/article/

002372.htm

Appendix

5 10 15 20 25 30101112131415

Cell 1 size in 0.07M NaCl

Cell 1

Time (mins)

Size

(µm

)

5 10 15 20 25 30789

101112131415


Cell 2

Time (mins)

Size

(µm

)

5 10 15 20 25 30101112131415


Cell 3

Time (mins)

Size

(µm

)

Appendix

5 10 15 20 25 30789

101112131415


Cell 1

Time (mins)

Size

(µm

)

5 10 15 20 25 30789

101112131415


Cell 2

Time (mins)

Size

(µm

)

5 10 15 20 25 30789

101112131415


Cell 3

Time (mins)

Size

(µm

)

Appendix

5 10 15 20 25 30101112131415161718


Cell 1

Time (mins)

Size

(µm

)

5 10 15 20 25 3010

11

12

13

14

15


Cell 2

Time (mins)

Size

(µm

)

5 10 15 20 25 3010

11

12

13

14

15


Cell 3

Time (mins)

Size

(µm

)