Answer Scheme Paper 3

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1

MARKING SCHEME : PAPER THREE – TRIAL BIOLOGY 2010 Question 1 : 1(a) Score Explanation Able to record all readings of volume of urine produced 3

Student A B C D

2 1 0

Volume of urine in the first experiment/ml 80 150 200 360

Volume of urine in the second experiment/ml 82 170 250 370

Able to record any 4-5 volume Able to record any 2-3 volume No response or wrong response 1(b)(i)

Score

3

2 1 0

Explanation Able to state two correct observations based on following criteria. C1 – volume of water intake C2 – volume of urine produced Sample Answer:(either 2): 1. When the volume of water intake is 100 ml, the volume of urine produced in first experiment is 80ml and second experiment is 82 ml. 2. When the volume of water intake is 400 ml, the volume of urine produced in first experiment is 360 ml and second experiment is 370 ml. Able to state one correct observation and one inaccurate response. Able to state one correct observation or two inaccurate response or idea. No response or wrong response (response like hypothesis) 1(b) (ii)

Score

3

2 1 0

Explanation Able to state two reasonable inferences for the observation. Sample answer: 1. When the volume of water intake is less, more water is reabsorbed, less urine is produced 2. When the volume of water intake is more, less water is reabsorbed, more urine is produced Able to state one correct inference and one inaccurate inference. Able to state one correct inference or two inaccurate inference or idea. No response or wrong response (inference like hypothesis)

Peperiksaan Percubaan Biologi SPM 2010 Panitia Biologi Negeri Perlis

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2

1(c) Score

Explanation Able to state all the variables and the method to handle variable correctly (√) for each variable and method Manipulated Variable: Volume of water intake (√) Method to handle: Repeat the experiment by drinking different volume of water (√) Responding Variable: Volume of urine produced (√) Method to handle: Measure and record the volume of urine produced after half an hour by using measuring cylinder.(√)

3

Controlled variable : type of water intake/ duration to collect urine (√) Method to handle: . drink same type of water/ fix the time to collect urine (√) Able to get 6 √ (with the correct key words) Able to get 4 – 5 √ Able to get 2 – 3 √ No response or wrong response

2 1 0

1(d) Score

3

2 1 0

Explanation Able to state the hypothesis correctly based on the following criteria: V1 – State the volume of water intake V2 – State the volume of urine produced R - State the relationship between V1 and V2. The more the volume of water intake, the more the volume of urine produced. Able to state the hypothesis but less accurate. Able to state the idea of the hypothesis No response or wrong response 1(e)(i)

Score

Explanation Able to construct a table and record the result of the experiment with the following criteria: – volume of water intake(ml) (√) – average of volume of urine produced (ml) (√) - percentage of urine produced (%) (√) If without unit (x)

3 Students A B C D 2 1 0 1(e)(ii)

Volume of water intake/ml 100 200 300 400

Volume of urine produced/ml First Second experiment experiment 80 76 150 170 250 250 360 370

Able to construct a table and record any two criteria Able to construct a table and record any one criteria No response or wrong response

Peperiksaan Percubaan Biologi SPM 2010 Panitia Biologi Negeri Perlis

Average of volume of urine produced/ml 78 160 250 365

Percentage of volume of urine produced / % 78 80 83 91

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Score

3

Explanation Able to draw a bar chart of percentage of urine produced against the volume l of water intake. Axes (A) – both axis are labeled with units, uniform scales, independent variable on horizontal axis. (√) Point (P) – All points are correctly plotted. (√) Shape (S) – All bars are correctly drawn (√).

3

2 1 0

Graph with any two criteria. Graph with any one criteria. No response or wrong response. 1(f)

Score

3

2 1 0

Explanation Able to explain the relationship between the volume of water intake and the volume of urine produced correctly. When the volume of water intake is more, the volume of urine produce also more because less water is reabsorbed Able to explain briefly the relationship between the volume of water intake and volume of urine produced Able to explain the idea the relationship between the volume of water intake and volume of urine produced No response or wrong response 1(g)

Peperiksaan Percubaan Biologi SPM 2010 Panitia Biologi Negeri Perlis

Skema jawapan biologi

Score

3

2 1 0

4

Explanation Able to state the definition of urine correctly, based on the following criteria. C1 – waste product (in the form of liquid) C2 – excreted by human C3 – influence by volume of water intake Urine is a waste product in the form of liquid excreted by human and influent by the volume of water intake Able to state the definition of urine based one of the two criteria. Able to state the idea of urine No response or wrong response 1(h)

Score

3

Explanation Able to predict correctly and explain the prediction based on the following item: C1 – the volume of urine produced C2 – blood osmotic pressure C3 - reabsorption of water The volume of urine produced is less than 78 ml because after drinking 5% sodium chloride solution, the blood osmotic pressure increases , therefore more water is reabsorbed thus the volume of urine produced is less.

2 1 0

Able to predict based on any two criteria. Able to predict based on any one criteria. No response or wrong response 1(i)

Score

Explanation Able to classify the apparatus and material used in the experiment

3

Apparatus Measuring cylinder Drinking bottle Stopwatch

Materials Plain water

Able to classify all the apparatus and material correctly. 2 1 0

Able to classify two apparatus and one material correctly. Able to classify one apparatus and one material correctly. No response or wrong response

Question 2 : Peperiksaan Percubaan Biologi SPM 2010 Panitia Biologi Negeri Perlis

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Peperiksaan Percubaan Biologi SPM 2010 Panitia Biologi Negeri Perlis

5

Aspect Problem statement

Sample Answer

Remarks

Which water sample is most polluted? /

3 marks

Skema jawapan biologi Which area contains water that 6 is most polluted?

Aim/objective

To study the level of water pollution in three different water samples.

√

Hypothesis The nearer the area of water sample to the factory/farm, the higher the level of water pollution.

3 marks

Variables Manipulative variable: river water samples Responding variable: time taken for methylene blue solution to decolourise Fixed variable: volume of water sample/concerntration of methylene blue solution Apparatus and materials

Apparatus:

measuring cylinder, stopwatch, reagent bottle, collecting cup

Materials : 0.1% methylene blue solution, water samples

Technique used

Observe and record the time taken by methylene blue solution to decolourise

√

All present – 3 marks 2 materials and 3-4 app – 2 marks 2 materials and 2 app – 1 mark B

Procedure

1. Water sample are collected from three different area by

Presentation of data

using collecting cup –KP,KMV 2. Three reagent bottles are labelled X,Y and Z and filled with 100 ml of water sample from village X, Y and Z respectively.-KFV & KMV 3. The tests are run for all the water samples on the same day-KP, KFV 4. A syringe is used to add 1 ml of 0.1% methylene blue solution to the base of each the water sample.KP, KFV 5. Make sure the reagent bottles are closed quickly and placed in the dark cupboard.-KC 6. The stopwatch is started.-KP 7. The bottles are examined at 1 –hour intervals- KP, KFV 8. The time taken for the methylene blue to decolourise is recorded for all the water samples- KRV 9. The results are recorded in the table .KP Able to draw a complete table to record the relevant data base on the 3 criteria: • Water samples • Time taken for methylene blue to decolourise • Level of water pollution

8 - 9P – 3 m 6 - 7P – 2 m 3 - 5P – 1 m 3 marks √

KP – Step 1,3,4,6,7,9 (any 5) KMV – Step 1,2 KRV – Step 8, KFVStep2,3,4,7 KC – Step 5

Sample Answer Water sample Time taken for methylene blue Peperiksaan Percubaansolution Biologi to SPM 2010 decolourise/min Panitia Biologi Negeri Perlis Level of water

X

Y

Z √ B

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7 END OF MARKING SCHEME

Peperiksaan Percubaan Biologi SPM 2010 Panitia Biologi Negeri Perlis