2012 MRSM Paper 3 (Answer)

Question 1:

a)      94, 62, 46

b)      i)
1. The volume of urine collected after taking distilled water is 94ml.
2. The volume of urine collected after taking 10.0% of drinking water is 46ml.
ii)
1. The volume of urine collected is the highest after taking distilled water because osmotic pressure decreases, volume of water reabsorb at the kidney tubule decreases.
2. The volume of urine collected is the lowest after taking 10.0% drinking water because osmotic pressure increases, volume of water reabsorb  at the kidney tubule increases.

c)       MV: Concentration of drinking water   à use different concentration of drinking water.

RV: volume of urine collected à measure and record the volume of urine collected by using a measuring cylinder.
CV: Volume of drinking water à fix the volume of drinking water at 500ml.

d)      The higher the concentration of drinking water, the lower the volume of urine produced.

e)      I)

Concentration of drinking water (%)	Volume of drinking water (ml)	Volume of urine collected (ml)	Percentage of water reabsorbed by kidney (%)
0.0	500	94	81.2
5.0	500	62	87.6
10.0	500	46	90.8

f)       As the concentration of drinking water intake increases, the percentage of water reabsorbed increases.  This is because the osmotic pressure increases, therefore volume of water reabsorb increases.

g)      The volume of urine collected will be more than 94ml.  this is because caffeinated drink causes the volume of water reabsorb at the kidney tubule decreases.

h)      Osmoregulation is a process of maintaining osmotic pressure of the blood which can be determine by the volume of urine collected ; the volume of urine collected is affected by the concentration of drinking water.

i)         

Variable	Apparatus	Material
Manipulated	Drinking cup	Sodium chloride solution
Responding	Measuring cylinder	Urine collected
Controlled	Stopwatch	student

Question 2:

Problem statement: What is the effect of concentration of carbon dioxide on the rate of photosynthesis of Hydrilla sp.
Hypothesis: The higher the concentration of carbon dioxide, the higher the rate of photosynthesis of Hydrilla sp.
Variables:
MV: Concentration of carbon dioxide
RV: Number of air bubbles release in 10 minutes
CV: Light intensity  OR  distance of Hydrilla sp. Plant from the light source
Apparatus:  Glass funnel, light source, 60W bulb, beaker( 500ml), stopwatch, meter ruler, thermometer.
Material: Hydrilla sp., plasticine, distilled water, sodium hydrogen carbonate 2%, 4%, 6%, 8%.
Experimental Procedures: pls refer to your reference book/form 4 notes for procedures.
Presentation of Data:  

Concentration of sodium hydrogen carbonate  (%)	Number of air bubbles release in 10 minutes	Rate of photosynthesis (min-1)
2
4
6
8