6 nutrition p3a

4551/3 Nutrition Biology Paper 3

CHAPTER 6 : NUTRITION

2005 2006 2007 2008 (1) (1)

ANSWERYEAR 2005

1 An experiment was carried out to determine and compare the energy content in white bread and peanuts.The mass of each food sample used was 5g.The volume of distilled water used was 20 ml.The density of water is 1 gm/-1

Figure 1 shows the set-up of the apparatus used in the experiment

Answer To Score Jabatan Pelajaran Perak 2009®1


Figure 2 shows the initial water temperature for each food sample.


29

34

40


Table 1 shows the highest water temperature after each food sample is completely burnt.

(a) (i) Record the initial water temperature in the space provided in Figure 2.

(ii) Record the final water temperature in the boxes provided in Table 1. [3 marks]

(b) (i) State two different observations made from Table 1.1 The temperature of water after burning white bread is 34˚ C.

2 The temperature of water after burning peanut is 40˚C [3 marks]

(ii) State two inferences from the observations in (b)(i).1 White bread burnt and releases low heat energy.

2 Peanut burnt and releases high heat energy [3 marks]

(c) Complete Table 2 based on the experiment that was carried out.

Variables Particulars to be implemented

Manipulated variableFood sample/white bread and peanut

How to alter the manipulated variableUse different food sample i.e white bread and peanut

Responding variableTemperature changes/energy value of food sample

How to determine the responding variableMeasure and record the increase in temperature of water by using a thermometer.Calculate the energy value using the given formula

Controlled variableMass of food sample.Air movement and temperature surrounding the experiment

How to maintain the controlled variableUse the same mass of each sample foodEnsure air movement and temperature surrounding the experiment is the same.

TABLE 2[6 marks]

(d) State the hypothesis for this experiment. The rise in temperature for peanut is higher than whitebread./ The energy value for the peanut is higher than the whitebread.

[3 marks]

(e) (i) Construct a table to record the results of this experiment. Your table should contain the following titles: ∙ Food sample ∙ Increase in water temperature ∙ Energy value

Specific heat capacity of water is 4.2 Jg-1C˚ -1

Use the formula:Energy value = Mass of water x specific heat capacity of water x temperature increase



Mass of food

Food sample Increase in water temperature (˚C)

Energy value (Jg -1)

White bread 5 84.0Peanut 11 184.8

[3 marks]

(ii) Based on the table in (e)(i), state the relationship between the food class and the energy value of each food sample. White bread contains carbohydrate. Peanut contains a lot of fat. Hence, peanut has

higher energy value than whitebread. [3 marks]

(f) Based on the result of the experiment, what can you deduce about the energy value? The energy value is the total quantity of heat energy produced when 5g of whitebread

is completely burnt in order to increase the temperature of 20ml of water up to 5˚C./ The energy value is the total quantity of heat energy produced when 5g of peanut is completely burnt in order to increase the temperature of 20ml of water up to 11˚C. [3 marks]

(g) This experiment was repeated using a cashew nut. Predict the observation and the energy value that will be obtained. The increment of temperature and energy value of cashew nut is equal to the

increment of the peanut. (for the equal amount of mass) [3 marks]

(h) The picture shows various types of food samples: Margarine, rice, palm oil, boiled potato, cashew nut and maize. Classify the food samples into two food classes in Table 3, based on the energy value that is equivalent to that of white bread or peanut.



Food samples with equivalent energy value as

white bread peanut

RiceBoiled potato

Corn

MargarinePalm oil

Cashew nut

TABLE 3[3 marks]

2007

1. An experiment was carried out to investigate the effect of light intensity on the rate of photosynthesis of a Hydrilla sp. sprig

The following steps were carried out..

Step 1 : 50 ml of 2% sodium hydrogen carbonate solution was placed in a boiling tube.

Step 2 : A Hydrilla sp. sprig was immersed in the sodium hydrogen carbonate solution.

Step 3 : A light source from a 60W bulb was placed at a distance of 60cm from the boiling tube.

Diagram I shows the apparatus set-up used in this experiment.



(a) In Table 1, list all the materials and apparatus labelled in Diagram 1.Materials Apparatus

2% sodium hydrogen carbonate solution, Hydrilla sp.

Boiling tube, 60W bulb, retord stand, ruler, paper clip

Table 1 (3 marks)Table 2 shows the results of this experiment.


10

15

20

12


(b) Record the total number of bubbles released in 5 minutes in the boxes providedin Table 2.

[3 marks](c) (i) State two different observations made from Table 2.

Observation 1 :If the distance between light source and Hydrilla sp. Is 60 cm, the total number of bubbles released in 5 minutes are 10.

Observation 2 :

If the distance between light source and Hydrilla sp. Is 30 cm, the total number of bubbles released in 5 minutes are 20.

(ii) State the inference which corresponds to the observations in 1(c)(i). Inference from observation 1 :

The longer the distance between light source and Hydrilla sp.,the lower the light intensity. Hence the lower the amount of oxygen gas released in the boiling tube, the lower the rate of photosynthesis.

Inference from observation 2 :

The shorter the distance between light source and Hydrilla sp.,the higher the light intensity. Hence the higher the amount of oxygen gas released in the boiling tube, the higher the rate of photosynthesis

[3 marks]

(d) Complete Table 3 based on this experiment.

VariableMethod to handle the variable

Manipulated variable

Light intensityUse different distance between light source and Hydrilla sp. i.e : 60cm, 50cm, 40 cm, 30 cm

Responding variable

Total number of bubbles released in 5 minutes

Count and record the total number of bubbles released in 5 minutes

Constant variable

The concentration of sodium hydrogen carbonate solution, duration of exposure to

light source

Maintain the volume and the concentration of sodium hydrogen carbonate solution and the duration of exposure to light source

Table 3 (3 marks)(e) State the hypothesis for this experiment.

The higher the light intensity, the higher the rate of photosynthesis



(f) (i) Construct a table and record all the data collected in this experiment.

Your table should have the following titles:

- Distance between light source and Hydrilla sp.

- Total number of bubbles released in 5 minutes

- Light intensity

Use the formula:

1Distance between light source and Hydrilla sp.

Distance between light source and Hydrilla sp. (cm)

Light intensity (cm-1) Total number of bubbles released in 5 minutes

60 0.017 10

50 0.020 12

40 0.025 15

30 0.033 20

(f) (ii) Use the graph paper provided to answer this part of the question.

Using the data in 1(f)(i), draw the graph of the total number of bubblesagainst the light intensity. [3

marks]


Light intensity =

0.01 0.02 0.03 0.04

5

10

15

20

x

x

x

x

The total number of bubbles

Light intensity


(g) Based on the graph in 1(f)(ii), explain the relationship between the total number of bubbles and the light intensity.

The higher the light intensity the higher the total number of bubbles released

[3 marks]

(h) This experiment is repeated using two sprigs of Hydrilla sp.Predict the total number of bubbles released in 5 minutes by these two sprigs of Hydrilla sp.Explain your predictionWhen the number of Hydilla sp. sprigs is increased, the total number of bubbles released in 5 minutes become higher because the higher the number of Hydrilla sp. sprig, the higher the rate of photosynthesis.

[3 marks]

(i) Based on the result from this experiment, what can be deduced about photosynthesis?

The rate of photosynthesis is the total number of bubbles released in 5 minutes by Hydilla sp. and is affected by light intensity.

[3 marks]
