PEPERIKSAAN AMALI SPM

TING 4 BAB 6 NUTRISI

QUESTION 1

(20 MARKS)

Energy is needed to perform physical activities. The energy required by the body is generated by the oxidation of molecules obtained from food during cellular respiration. The energy content of a particular food can be measured by burning a known mass of the food completely in the presence of oxygen. The amount of

heat generated from the combustion of one gram of food is known as the energy value of the food. The unit used to describe energy values in food is joule per gram (Jg-1).

Energy content of foods can be determined by using a laboratory experiment.

The aim of this experiment is to determine and compare the energy content in food samples PA and PB. You are provided with distilled water, food sample A and B, plasticine.

Diagram 1

Based on diagram 1, plan and carry out the experiment to determine and compare the energy content in food samples PA and PB.

Diagram 1 shows the set up for this experiment. Carry out this experiment by using the following steps:

i. Weigh the food sample PA and record the mass. ii. Fill one boiling tube with 20ml of distilled water.

iii. Set up the apparatus as shown in diagram 1. iv. Record the initial temperature of the water. v. Burn the food sample PA and put it as near as possible to the bottom of the boiling tube.

vi. Stir the water. vii. The thermometer must not be allowed to touch the base of the boiling tube.

viii. Read and record the highest temperature when the food sample PA has stop burning.

ix. Repeat step i till viii to get the average temperature rise for food sample PA. x. Repeat step I till ix by using food sample PB.

Based on the experiment which have been carried out, answer the following questions:

a) Construct a table and record your readings.

3m

b) State why the temperature of the distilled water increased?

1m c) Calculate the energy value of foo sample PA.

2m d) State a reason why thermometer cannot touch the bottom of beaker.

1m

e) (i) If sample food PA is replaced by cashew nut, predict the energy content of cashew nut.

1m (ii) Give reason for your answer.

1m

f) Based on this experiment, state the operational definition of energy value.

2m

g) You are required to repeat this experiment by replacing food sample PA with food sample PB. Explain the difference in the energy content of food sample PA and food sample PB.

2m h) Margarine, rice, palm oil, boiled potato, cashew nut and maize .

Classify the food samples into two food classes in Table 1, 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

Table 1 2m

i) (i) Based on this experiment, state the following variables: Manipulated variable :

Responding variable:

2m (ii) State the hypothesis for the experiment in 1 (i) (i).

3m

QUESTION 2

(10 MARKS)

2. This experiment is carrying out to study sex determination in offspring. White button represents an ovum carrying an X chromosome.

Black button represents sperms carrying an X chromosome. Red button represents sperms carrying Y chromosome.

a) Place the white buttons in a petri dish. b) Put 25 red buttons and 25 black buttons in a black plastic.

c) Shake the plastic bag and use your hand to mix the buttons inside. Without looking into the bag and take out one button. Place it in the petri dish as diagram 2.

d) Record the number of times the red of black button is taken out. Each time, put the red button or black button into the bag.

e) Repeats steps c) – to d) for 49 times.

Diagram 2

The result is recorded in table 2.

Combination of buttons Number of times Sex

1 white button + 1red button 24

1 white button + 1 black button 26

Table 2

Based on the experiment which have been carried out, answer the following questions:

a) Determine the sex of the offspring by completing Table 2.

2m

b) Explain why a female only produces ova with X chromosomes.

2m

c) Draw a schematic diagram to illustrate sex determination in offspring of humans.

3m

d) Which parent is responsible for determining sex of a child? Explain your answer.

3m

End of Question Paper