Answering Techniques For SPM 2011 Paper 3 (Question 1)

For this post, please refer to Terengganu State Trial Paper 3 2011
Percubaan SPM Biology Terengganu 2011 P3


Introduction:

1. Answer all questions
2. Consists of question 1 (33 marks) and question 2 (17 marks) = 50 marks in total
3. The marks ranged from:
• 0 (wrong response), 
• 1 (idea level),
• 2 (inaccurate response) 
• 3 (accurate response)

Now let's get down to business, shall we?


QUESTION 1
"Know thy self, know thy enemy. A thousand battles, a thousand victories"
                                                                                                     Sun Tzu


Read the question carefully.
Identify manipulated variable, responding variable and fixed variable

Question 1(a)(i)

When answering this question take note of:

1. the S.I unit for your observation
2. some questions needed you to do a conversion.For example: the diagram shown use gram but the column for answer might want you to answer in kg
3. the number of decimal places must be suitable with the type of apparatus used.

Question 1(b)(i)

State two different observations made from Table 1
A good observation have 3 criteria: MV, RV and the quantity observed

There are 2 ways to write an observation:

1. Horizontal (your observation is directly on one condition of MV, no comparison) : 
• When/At MV the RV is observation
• Example: When 2% concentration of sucrose solution is used, the final mass of water spinach after 30 minutes is 50g.
2. Vertical (your observation is on several conditions and you compare them)
• The RV in MV condition A is higher/lower compared to RV in MV condition B and C
• Example: The final mass of water spinach in 2% sucrose solution is higher compared to the final mass of water spinach in 4% and 6% sucrose solution.

The best way to write a complete MV and RV is by referring to the title of columns representing MV and RV in table 1.

Note :

I always encourage my students to 

• write observation type 1 (horizontal) because it is direct and less prone to mistakes
• write observation that shows highest and lowest value (for experiments that observe measurements) or positive and negative results (for experiments that observe changes in colour or condition)

Question 1(b)(ii)

State the inferences which corresponds to the observation 1 (b)(i).

Since there are 2 types of observations, there are also two types of inferences

1. Horizontal inference:
• The RV is high/low because reason 1/point 1 so reason 2/point 2
• Example : The final mass of water spinach after 30 minutes is high because the solution is hypotonic towards the cell sap of water spinach so water will diffuse into water spinach via osmosis.
2. Vertical inference:
• The RV is the highest/lowest because more reason 1/point 1 so more reason 2/point 2
• Example: The final mass of water spinach after 30 minutes is higher because the solution is more hypotonic towards the cell sap of water spinach so more water will diffuse into water spinach via osmosis

See the difference? 

Question 1(c)

Complete  Table 2 based on this experiment

1. Manipulated variable
• Refer to the title of column representing MV in table 1
• Example:Concentration of sucrose solution
• Method to handle MV:
• Use different MV which is (conditions of the experiment)
• Example: Use different concentration of sucrose solution which is 2%, 4%, 6%, 8% and 10%)
2. Responding variable
• Type 1: Refer to the title of column representing MV in table 1
• Example 1: The final mass of water spinach after 30 minutes
• Type 2: Refer to the calculation that you will do in 1(e)(i)
• Example 2:The percentage change in mass
• Method to handle RV:
• For type 1: Observe, *Observe/measure/count and record RV using (state apparatus used)
• Example: Observe, measure and record the final mass of water spinach using weighing scale.
• For type 2: Calculate and record RV using the formula: (formula)
• Example:calculate and record the percentage change in mass by using formula :             = ( final mass – initial mass)/initial mass   x   100
3. Constant variable:
• Use variables that are stated in the question and choose the one that has values
• Example: Duration of immersion/, Size /length/mass of potato strips,volume of sucrose solution
• Method to handle CV:
• Fix/Use the same/Maintain CV at/which is (condition of CV)
• Example: Fix the time/duration for the immersion of the potato strips at 30 minutes.       Use the same volume of sucrose solution which is 20 ml

Question 1(d)

State the hypothesis for this experiment.

The things that should be included in your hypothesis is

1. MV
2. RV
3. relationship

The higher/lower MV, the higher/lower RV.

Example: The higher the concentration of sucrose solution the lower the final mass of water spinach after 30 minutes.

But for certain experiments, where the conditions are not values, like type of water sample (for BOD experiment) or RV shows positive result in only one condition like pH value (effect on the activity of yeast and effect on the activity of enzyme experiment), the way to write hypothesis is similar to writing a vertical observation

The RV in MV condition A is higher/lower compared to RV in MV condition B and C

Example : The BOD value in drain water is higher compared to pond water and river water.

                Yeast activity is higher in neutral condition compared to acidic and alkaline condition.

See the difference?

Question 1(f)

Based on the graph in 1 (e)(ii), state the concentration of the sucrose solution which is remain unchanged the mass of water spinach strips.Explain your answer.

The concentration of the sucrose solution which is remain unchanged the mass of water spinach strips is (your answer) because reason 1/point 1 so reason 2/point 2.

Example: 

The concentration of the sucrose solution which is remain unchanged the mass of water spinach strips is 5.4% because the rate of water diffuse into and out of water spinach  are at the same rate (or you can  say: the solution is isotonic towards the cell sap of water spinach) 
so, no percentage change in mass of water spinach.

But for other experiments the question can be like this:

Based on the graph in 1 (e)(ii), state the relationship between A  and B.Explain your answer.

The higher/lower A, the higher or lower B because more/less reason 1/point 1 so more/less reason 2/point 2.

Example:

The higher the light intensity, the higher the rate of photosynthesis because more light energy is available to do photolysis of water, so more oxygen will be produced.

Question 1(g)

What can be deduced about definition of osmosis?

For most questions, the operational definition/deduction will be on or related to RV. 

Osmosis is (theoretical definition) which can be seen by/ determined by RV affected by MV

Example:

Osmosis is the movement of water across plasma membrane  determined by the final mass of water spinach after 30 minutes affected by the concentration of sucrose solution.

Question 1(h)

Experiment was repeated by taking out the water spinach strips from 10% 

concentration of sucrose solution and was dried up with tissue paper.  Then it was immersed in distilled water for 30 minutes. Based on the result of this experiment, predict what will happen to the water spinach strip. Explain your prediction

The RV will be more/less than (RV value when experiment was conducted in similar condition)  because reason 1/point 1 so reason 2/point 2.

Example:

The final mass of water spinach will be more than 30g (because when experiment was conducted in 10% sucrose solution, the observed value is 30g) because distilled water is hypotonic towards the cell sap of water spinach, so more water will diffuse into it via osmosis.

That concludes Question 1. As you can see, for most questions the criteria/points for your answer are almost the same. That's why it is crucial to identify MV, RV and CV correctly before starting to answer.