osmosis

Q2 MARKING SHEME 1 (SPM 2006)Topic 3.3: Movement of substances across the plasma membrane Objective : To determine the concent ratio n of sucrose solution which is isoto nic to the cell sap of the spinach. [tick 1] Problem statement: [SPS 12 -01: 3 Ma rks] : [ t ick 2 ] Does the length of cylindrical strips spinach remain unc hanged when th e cylindrical strips are immersed into the sucrose solution which is isotonic to the spinach tissue ? Variables: [ tick 3] Manipulated variable: sucrose solution concentration Responding variable: the final length of cylindrical strips of mangoes Fixed variable: initia l length of cylind rical stri ps of mangoes // volume of sucrose solution Hypothesis: [SPS 12 -02 : 3 Ma rks] : [ t ick 4 ] The length of cylindrical strips spinach’s remain unchanged when the cylindrical strips are immersed into the sucrose solut ion which is isotonic to the spina ch tissue. Materials /Apparatus : [SPS 12 -05 : 3 Ma rks] : [t ick 5] Cork borer, scalpel, test tube, stop watch, b eaker and ruler spinach, sucrose solution (0.1M,0.2 M,0.3M,0 .4M,0.5M), distilled water, filter paper Technique: [SPS 12 -B1 : 1 Ma rk] : [t ick 6 ] measure the final length of cylindrical strips of mangoes using a ruler Working procedures: [SPS 1 2-04 : 3 Ma rks] [ t ick 7] 1. Labe l six tes t tube s with P ,Q,R,S, T and U. 2. Fill in 5 ml dist ille d water in tes t tube P, 5 ml 0.1M su cros e solut ion in test tu be Q, 5 ml 0.2 M sucrose solution in test tube R, 5 ml 0.3M sucrose solution in test tube S, 5 ml 0.4 M sucrose solution in test tube T and 5 ml 0.5 M sucrose solution in test tube U. 3. Cu t th e spi nach stem into 4 strip s to get 5.0 mm in length. 4. Repe at st ep 3 & 4 to ge t an othe r five spinachl strips of the same length. 5. Wipe dry each spinach strip with filter paper. 6. Put ea ch cylindrical strip into each test tube for about 40 minutes. 7. After 40 minut es , tak e ou t th e spinach strip from each test tube and place it on a piece of filter paper to wipe it dry. 8. Meas ure the f inal leng th of each spinach strip and record the reading in the table. 9. Plot a graph of the percenta ge difference in leng th against the conce ntration pf the sucrose solution to determine the concentration of sucrose solution which is isotonic to the cell sap of the spinac h.

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Q2 MARKING SHEME 1

(SPM 2006)Topic 3.3: Movement of substances across the plasma membrane

Objective : To determine the concentration of sucrose solution which is isotonic to the cell sap ofthe spinach. [tick 1]

Problem statement: [SPS 12-01: 3 Marks] : [ tick 2]

Does the length of cylindrical strips spinach remain unchanged when the cylindrical strips areimmersed into the sucrose solution which is isotonic to the spinach tissue?

Variables: [ tick 3]Manipulated variable: sucrose solution concentrationResponding variable: the final length of cylindrical strips of mangoesFixed variable: initial length of cylindrical strips of mangoes // volume of sucrose

solution

Hypothesis: [SPS 12-02 : 3 Marks] : [tick 4]

The length of cylindrical strips spinachs remain unchanged when the cylindrical strips are immersedinto the sucrose solution which is isotonic to the spinach tissue.

Materials /Apparatus : [SPS 12-05 : 3 Marks] : [tick 5]

Cork borer, scalpel, test tube, stop watch, beaker and rulerspinach, sucrose solution (0.1M,0.2M,0.3M,0.4M,0.5M), distilled water, filter paper

Technique: [SPS 12-B1 : 1 Mark] : [tick 6]measure the final length of cylindrical strips of mangoes using a ruler

Working procedures: [SPS 12-04 : 3 Marks] [ tick 7]

1. Label six test tubes with P,Q,R,S,T and U.2. Fill in 5 ml distilled water in test tube P, 5 ml 0.1M sucrose solution in test tube Q, 5 ml 0.2 M

sucrose solution in test tube R, 5 ml 0.3M sucrose solution in test tube S, 5 ml 0.4 M sucrosesolution in test tube T and 5 ml 0.5 M sucrose solution in test tube U.

3. Cut the spinach stem into 4 strips to get 5.0 mm in length.4. Repeat step 3 & 4 to get another five spinachl strips of the same length.5. Wipe dry each spinach strip with filter paper.6. Put each cylindrical strip into each test tube for about 40 minutes.7. After 40 minutes ,take out the spinach strip from each test tube and place it on a piece of filter

paper to wipe it dry.8. Measure the final length of each spinach strip and record the reading in the table.9. Plot a graph of the percentage difference in length against the concentration pf the sucrose

solution to determine the concentration of sucrose solution which is isotonic to the cell sapof the spinach.
Results: [SPS 12-B2 : 1 Mark] : [ tick 8]

Testtube Length Percentage

difference inlength (%)

initial (mm) final (mm) Different inLength (mm)

P 50.0

Q 50.0

R 50.0

S 50.0

T 50.0

U 50.0

Conclusion: [ tick 9]The length of spinach strips remain unchanged when the strips are immersed into the sucrose solutionwhich is isotonic to the spinach tissue. Hypothesis is accepted.