Water Passaes Through Cell Membranes From Areas Of High Water Concentration
To Areas Of Low Water Concentration. This Movement Of Water Is Called Osmosis. If A Cell Is Placed In An Enviroment In Which The Concentration Of Water Is Less Than That Inside The Cell, Water Will Flow From The Cytoplams Through The Membrane Into The Enviroment. The Cytoplams Of The Cell Shrinks. Away From The Cell Wall. This Water Removal Is Called Plasmolysis.
A Scientist Can Observe The Effects Of Water Loss By Observing The Shrinking Of A Cell’s Cytoplams With A Misroscope. This Observation Is A Qualitative Measurement. In Measuring The Amount Of Water Loss In Grams, A Scientist Makes A Quantitative Measurement.
The Purpose Of This Investigation Is Observe The Qualitative Effects Of Plasmolysis In Elodea Cells And To Quantitatively Measure The Rate Of Plasmolysis In Potato Slices.
Part A:
Qualitative Plasmolysýs:
Materials:
Elodea Sprigs
Microscope
Glass Slide
Cover Slip
Water
Dropper
5% Sodium Chloride Solution-5ml
10% Sodium Chloride Solution-5ml
Distilled Water
Procedure:
Part A: Qualitative Plasmolysýs
Make A Wet Mount Of An Elodea Leaf. Locate Epidermal Cells On Lower Power And Then An High Power Of Your Misroscope. Place Two Drops Of 5% Sodium Chloride Solution Along One Edge Of The Cover Slips. Draw The Salt Solution Across The Slde By Placing A Small Section Of A Paper Towel On The Oppisite Side Of The Cover Slip. (figure 1)
Observe The Effectes Bof Solution On The Cells. Replace The Sodium Chloride Solution With Distilled Water In The Same Manner That The Sodium Chloride Was Added. Observe The Results In High Power.
Make Another Elodea Wet Mount And Repeat This Procedure Using A 10% Sodium Chloride Solution.
Results:
Part B:
White Potatoes-2
Beakers,250ml-4
Balance
Paper Towel
Glass Marking Pencils
Distilled Water-75ml
5% Sodium Chloride Solution-75ml
10% Sodium Chloride Solution-5ml
15%sodium Chloride Solution-75ml
Single Edge Razor Blade
Part B:quantitative Plasmolysýs
Cut A White Potato Into 8 To 12 Slices. Each Piece Should Be About 1 Cm Thick.
Determine The Mass Of The Potato Of Three Potato Slices In Table 1.
Put A Stack Of Potatoes Into Each Of Four Beakers. Label The Beakers A,b,c And D. To Beaker A Add 75 Ml Distilled Water; To Beaker B Add 75 Ml 5% Sodium Chloride Solution; To Beaker C Add 75 Ml 10% Sodium Chloride Solution; To Beaker D Add 75ml 15% Sodium Chloride Solution. After 20 Minutes Remove The Potato Slices From The Stack. In The Table, Record The Mass Of Each Stack After Soaking. In Rows 3 And 4 Of The Table, Indicate The Amount Of Increase Or Decrease In Mass Of Each Stack. Calculate The Percent Change By Using The Formula:
Amount Of Increase Or Decrease *100= % Change
Mass Before
Observe The Appearance Of Each Slice Of Potato. Record A Brief Description Of The
Potato Slices.
Table1. Change In Mass Of Potato Stacks
Beaker A Beaker B Beaker C Beaker D
Mass Before 7.88 7.55 8.00 6.50
Mass After 8.10 6.77 7.14 5.83
Amount Of Increase 0.12
Amount Of Decrease 0.78 0.68 0.77
Percent Change 1.5 10.33 8.5 0.11
Finding The Percent Change Of Potatos Using The Formula:
A Final Paragraph To Explain The Result Of These Two Experiments:
When We Added %5 Sodium Chloride The Cytoplasm Of The Elodea Leaf Got Smaller. When We Added Distilled Water The Chloraplast Of The Elodea Leaf Got Far Away From Each Other. When We Added %10 Sodium Chloride To The Elodea Leaf The Chloraplasts Were Nearer To Each Other More Than %5 Sodium Chloride. I Think That If I Drink Salt Water My Cytoplasms Will Be Bigger And Will Come Nearer To Each Other.
Beaker A’s Potato Got The Bigger Mass After 20 Minutes Of Immersion. Beaker D’s Potato Lost The Most Of The Mass. Beaker A’s Mass Increased But Beaker’s B,c,d Decreased.
Kerým Kiziler 10/ib/tm 4/12/2002
Lab Report
Density And Location Of Temperature And Touch Receptors
There Are Several Distinct Types Of Receptors In The Skin. Each Receptor Detects A Specific Type Of Stimuli. For Example, There Are Touch Receptors, Pain Receptors, Temprature Receptors And Pressure Receptors. Mapping These Sensations On The Skin Has Revealed That These Specialized Sensory Receptors Have Discrete Locations And Are Characterized By Clustering At Certain Points Rather Than A Uniform Distribution.
The Pain Receptors, Extremely Important In Protecting The Body, Are The Most Numerous. Touch And Temprate Receptors Seem To Cluster Where Greater Sensitivity Is Desirable, As On The Hands And Face. It Is Surprising To Learn That Rather Large Areas Of Skin Are Insensitive To Touch Because Of Lack Of Touch Receptors.
Supplies: 3different Colored Markers (fine Tip)
Ruler
Toothpick
Heated Glass Rod
Cooled Glass Rod
Procedure:
1. Draw A Square (20 Mm On Each Side) With A Felt Marker On The Vental Surface Of The Subjet’s Forearm.
2. Subjet’s Eye’s Must Remain Closed.
3. Obtain A Cold Glass Rod From The Ice Bath. Dry The Rod Quickly.
4. Working In A Systematic Manner ( Up And Down The Square) Gently Touch The Tip Of The Rod To Different Points Within The Square. When The Subjects Detects Cold, S/he Should Reply ‘’cold’’
5. Mark With One Of The Colored Markers All The Places In The Square Where The Subject Can Feel Cold.
Repeat The Steps Using A Hot Glass Rod For ‘’hot’’ And A Tooth Pick For ‘’touch’’
Copy The Square From Your Forearm Onto The Space Provided Below.
Receptors
Number Of Touch:
Number Of Heat:
Number Of Cold:
Copy The Your Partner’s Square Here. (ayça)
Receptors
Number Of Touch:
Number Of Heat:
Number Of Cold:
Conclusion:
There Are More Touch Receptors Than Heat Receptors. Because Me And Ayça Felt Heat More. Touch Receptors Have More Density Than Cold Receptors But Just A Little More. Touch Receptors Are Most Abundant Receptors. We Think Touch Receptors Are The Most Abundant Because We Felt Them More. And We Wouldn’t Like To Have Same Arragement On Our Bottom Of Our Foot Becuse The Skin Is More Thick And The Number Of Receptors Are Less.
Kerým Kiziler 10/ib/tm
Lab Report 3 4/12/2002
Two-point Discrimination Test
The Density Of Touch Receptors Varies Significantly In Different Areas Of The Body. In General, Areas That Have The Greatest Density Of Tactile (touch) Receptors Have A Heightened Ability To Feel. These Areas Seem To Correspond To The Areas That Have The Greatest Amount Of Precise Motor Control.
Supplies: Tweezers
Ruler (mm)
Procedure:
1. The Subject’s Eyes Should Be Closed During The Entire Experiment.
2. Start With The Tweezer’s Arms Tightly Closed Together And Touch The Subject’s Forehead. Do Not Apply Pressure.
3. Gradually Increase The Difference Between The Arms Of The Tweeters, Testing The Subject’s Skin After Every Adjustment.
4. Continue This Process Until The Subject Reports That Two Points Of Contact Can Be Felt.
5. Measure The Distance Between The Arms Of The The Tweeters. This Measurement, The Smallest Distance At Which Two Points Of Contact Can Be Felt Is The Two-point Threshold.
6. Repeat This Experiment On The Back Of Hand, Fingertip And Back Of Calf.
7. Record Your Results And Your Results And Your Partners In A Chart Listing The Body Area Tested An Two-point Threshold In (mm).
Conclusion:
We Had The Greatest Density Of Touch Receptors In Finger. Forehead Has The Least Density Of Touch Receptors. The Number Of Receptors Are Less Then The Number Of Receptor Of Forehead.
Kerým Kiziler 10/ib/tm
Lab Report 4/12/2002
Tactile Localization
Tactile Localization Is The Ability To Determine Which Portion Of The Skin Has Been Touched. The Tactile Receptor Field (each Different Part Of The Body) Has A Corresponding ‘’touch’’ Field In The Brain. Some Body Areas Are Well Represented With Touch Receptors, Which Allow The Brain To Know Precisely Where The Stimulus Is Coming From With Great Accuracy. Other Parts Of The Body Allow The Brain To Know A Crude Estimation Of Where The Stimulus Is Coming From.
Supplies: Two Different Colored Thin Tip-markers
Ruler
Procedure:
1. The Subject’s Eyes Should Be Closed During The Entire Experiment.
2. The Experimenter Touches The Palm Of The Subject’s Hand With A Marker.
3. The Subject Should Then Try To Touch The Exact Point Of Contact With A Different Colored Marker.
4. Measure The Area Between The Two Points In (mm). This Is The Error Of Localization.
5. Keep Ypur Data In A Chart. The Chart Should Include: Body Area, Attemps 1,2 And 3 And The Estimated Error Of Localization.
6. Repeat This Experiment In The Palm Of Hand, Fingertip, Ventral Forearm And Calf.
Conlusion:
The Ability Localize Stimuli Improve The Second Time And The Third Time. They Were Localize The Stimuli Because They Were More Stimulated.
Palm 1= 2mm Finger Tip 1= 1mm
Palm 2=1,5mm Finger Tip 2= 2mm
Palm 3=0,5mm Finger Tip 3=3mm
Forearm 1=2,5mm
Forearm 2=2mm
Forearm 3=2mm
Kerým Kiziler 10/ib/tm
Lab Report 4/12/2002
Adaptation Of Touch Receptors
The Number Of Impulses By Sensory Receptors Often Changes With Both The Intensity Of The Stimulus And Lenght Of Time The Stimulus Is Applied. In Many Cases, When The Stimulus Is Applied For An Extended Period Of Time, The Rate Of The Receptor’s Discharge Of Impulses Slows. This Causes A Decrease Or Complete Loss In Conscious Awareness Of The Stimulus Until Some Type Of Stimulus Change Occurs. This Phenomeon Is Referred To As An Adaptation. The Touch Receptors Adapt Rather Quickly, Which Is Highly Adaptable. For Example, Resting Your Arm On A Table. If This Adaptation Did Not Occur, You Would Constantly Feel The Table Under Your Arm.
Supplies: 5 Pennies
Clock With A Second Hand
Procedure:
1. The Subject’s Eyes Should Remain Closed During This Experiment
2. Place A Coin On The Anterior Surface Of The Subject’s Forearm.
3. Determine How Long It Takes For The Sensation To Persist For The Subject.
4. Record The Duration Of The Sensation In Seconds.
5. Do Not Remove The Coin. Add Four More Coins To The One Coin Already On The Arm
6. Record The Amount Of Time The Sensation Persists. You Do Not Need To Make A Char For This Portion.
Conclusion:
The Sensation Return When More Coins Are Added. Touch Receptors Are Stimulated When One Coin Is Placed On The Subject’s Arm. You Feel Pressure When You Add Coins.
I Didn’t Feel The Coins After One Minute.
Kerým Kiziler 10/ib/tm
Lab Report 4/12/2002
Referred Pain Is A Sensory Experience In Which Pain Is Perceived As Arising In One Area Of The Body, When In Fact Another Often Quite Remote Area Is Receiving The Painful Stimulus. The Pain Is Said To Be ‘’referred’’ To A Different Area. This Phenomenon Is Called Projection, The Process By Which The Brain Refers Sensations To Their Usual Point Of Stimulation.
Many Of Us Have Experience Referred Pain In The Forehead After Quickly Swallowing An Ice Cold Drink. Referred Pain Is Also Important In Clinical Diagnoses; For Example, Inadequate Oxygen Supply To The Heart Muscle (the Beginning Of A Heart Attack) Often Results In Pain Being Referred To The Chest And Shoulder.
Supplies: Water Bowl
ýce Cubes
Clock With A Second Hand
Procedure:
1. Immerse The Subject’s Elbow In A Bowl Filled With Ice Water.
2. Record The Quality (such As Tingling, Discomfort, Pain, Etc.) As Soon As The Elbow Is Immersed.
3. Record The Quality After One Minute.
4. Record The Quality After Two Minutes.
5. Enter Your Data In A Chart Labelled: Immersion, 1 Minute, 2 Minutes Quality Of Sensation, Location Of Sensation.
12 Seconds= A Little Cold
14 Seconds= A Little More
35 Seconds= Hurts A Little
45 Seconds= I Feel Pain
57 Second= My Hands Are Frozen
1,19= My Hands Are Frozen And Hurts More
1,40= I Want To Take Of My Hands
1,52 I Feel More Pain
2,00 I Am Very Happy Because I Took Of My Handsj
Kerým Kiziler 10/ib/tm 2159 19/12/2002
Lab Report 4
An Enzyme In Plant And Animal Tissues
This Practial May Be Formally Assessed For Data Collection, Data Processing/presentation And Conclusion/evalution
Certain Reactions Are Speeded Up By The Actions Of The Enzymes. In This Investigation The Effects Of Enzyme Catalase In Various Tissues Will Be Investigated.
Questions: Is Catalase Present In All The Tissues With Which You Will Work?
Materials:
2 Test Tubes
A Variety Of Animal Plant Tissues: Fresh Beef Or Lamb And Kidney, Potato, Apple Etc.
3 Percent Hydrogen Peroxide ( ) Solution
Graduated Cylinder (25-50ml)
Forceps
Paper Toweling
Bunsen Burner Or Other Heat Source
Experimental Design:
1. Use The Forceps To Take A Piece Of Each Of The Tissues And Place It On A Piece Of Paper Toweling. (do Not Touch Yhe Samples At Any Time With Your Fingers For You Do Not Want To Introduce Subtances Fom Your Own Skin Tissue.) Keep Each Piece Fom The Others On The Towel And Label The Towel For Indentification.
2. On A Second Piece Of Paper Toweling Take Identical Tissues That Have Been Boiled. Again Handle The Tissues With Your Forceps.
3. Take Two Clean Test Tubes And Pour 5 Ml Of Fresh 3% Solution Into Each Tube
4. Select An Untreated And Boiled Tissue Sample Of The Same Tissue And With The Forceps Place One Of Them In Each Tube
5. Observe And Record The Results
6. Empty The Tubes, Rimse Them And Again Pour 5 Ml Of Fresh 3% Solution Into Each Tube, Proceed As Before With Another Tissue Pair. Continue In This Manner Until You Have Tested All Tissue Pairs And Have Added The Results To Your Record For The First Pair.
Conclusion:
Boiled Meat Tissue Vegetable Tissues Aren’t Catalysed. We Can’t Observe Catalase On Them. But We Can Observe Catalase In Row Liver And Kidney Tissues. Human Tissue Contains Protein And Protein Is Relesed From The One Bowound And Wounded Are Catalase Activity Happens By The Enzyme.if You Increase The Rate Of Boiling The Enzymes Will Die.
Row Liver, Kidney, Potato And Apple Have More Catalase Because They Are Not Boiled.
Boiled
Liver: 6 Cm
Kidney: 4 Cm
Potato: 0,3 Cm
Apple: 1,0 Cm
Row => They Didn’t Have Bubbles Like The Boiled Ones In Our Experiment
Liver: --
Kidney: --
Potato: --
Apple: --
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