MARKING SCHEME : PAPER THREE – TRIAL BIOLOGY 2010 Question 1 : 1(a)
Score Explanation
3
Able to record all readings of volume of urine produced Student Volume of urine in the first
experiment/ml Volume of urine in the second experiment/ml
A 80 82
B 150 170
C 200 250
D 360 370
2 Able to record any 4-5 volume 1 Able to record any 2-3 volume 0 No response or wrong response
1(b)(i)
Score Explanation
3
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.
2 Able to state one correct observation and one inaccurate response. 1 Able to state one correct observation or two inaccurate response or idea. 0 No response or wrong response (response like hypothesis)
1(b) (ii)
Score Explanation
3
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
2 Able to state one correct inference and one inaccurate inference. 1 Able to state one correct inference or two inaccurate inference or idea. 0 No response or wrong response (inference like hypothesis)
1(c)
Score Explanation
3
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.(√)
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)
2 Able to get 4 – 5 √ 1 Able to get 2 – 3 √
0 No response or wrong response 1(d)
Score Explanation
3
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. 2 Able to state the hypothesis but less accurate.
1 Able to state the idea of the hypothesis 0 No response or wrong response
1(e)(i)
Score Explanation
3
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) Students Volume of water intake/ml Volume of urineproduced/ml Average of volume of urine produced/ml Percentage of volume of urine produced / % First
experiment experiment Second
A 100 80 76 78 78
B 200 150 170 160 80
C 300 250 250 250 83
D 400 360 370 365 91
2 Able to construct a table and record any two criteria 1 Able to construct a table and record any one criteria 0 No response or wrong response
Score Explanation
3
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 (√).
2 Graph with any two criteria. 1 Graph with any one criteria. 0 No response or wrong response.
1(f)
Score Explanation
3
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
2 Able to explain briefly the relationship between the volume of water intake and volume of urine produced 1 Able to explain the idea the relationship between the volume of water intake and volume of urine produced 0 No response or wrong response
Score Explanation
3
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
2 Able to state the definition of urine based one of the two criteria. 1 Able to state the idea of urine
0 No response or wrong response 1(h)
Score Explanation
3
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 Able to predict based on any two criteria. 1 Able to predict based on any one criteria. 0 No response or wrong response
1(i)
Score Explanation
3
Able to classify the apparatus and material used in the experiment
Apparatus Materials
Measuring cylinder Plain water Drinking bottle
Stopwatch
Able to classify all the apparatus and material correctly.
2 Able to classify two apparatus and one material correctly. 1 Able to classify one apparatus and one material correctly. 0 No response or wrong response
Skema jawapan biologi
Peperiksaan Percubaan Biologi SPM 2010 Panitia Biologi Negeri Perlis
Which water sample is most polluted? /
Which area contains water that is most polluted? 3 marks
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
All present – 3 marks 2 materials and 3-4 app – 2 marks 2 materials and 2 app – 1 mark Technique used Observe and record the time taken by methylene blue solution to
decolourise B
Procedure
1.
Water sample are collected from three different area by using collecting cup –KP,KMV2.
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 & KMV3.
The tests are run for all the water samples on the same day-KP, KFV4.
A syringe is used to add 1 ml of 0.1% methylene blue solution to the base of each the water sample.KP, KFV5.
Make sure the reagent bottles are closed quickly and placed in the dark cupboard.-KC6. The stopwatch is started.-KP
7.
The bottles are examined at 1 –hour intervals- KP, KFV8.
The time taken for the methylene blue to decolourise is recorded for all the water samples- KRV9.
The results are recorded in the table .KP8 - 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, KFV-Step2,3,4,7 KC – Step 5 Presentation of
data 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 Sample Answer
Water sample X Y Z
Time taken for methylene blue solution to decolourise/min √ B
