Download F4 C6 - Biology Form 5 Tests

CHAPTER 6 : NUTRITION
Year
Quantity
2003
3
2004
5
2005
8
2006
4
2007
6
2008
7
YEAR 2003
1
Four different food tests were carried out on a food sample. The results are
shown in
Table 1.
Test
tube
1
2
3
4
Test carried out
Biuret test
Benedicts test
Iodine test
DCPIP test
Observation
Violet solution
Blue solution
Dark blue
Colourless solution
Table 1
The food sample contains
I
protein
II
starch
III
vitamin C
IV
reducing sugar
A
B
C
D
2
I and IV only
II and III only
I, II and III only
I, II, III and IV
Figure 6 shows a step in the procedure to test starch in a leaf
Figure 6
What is the aim of the step in Figure 6?
A
To dissolve the chlorophyll
B
To soften the leaf
C
To extract the starch
D
To break down the cell wall
3.
Figure 27 shows part of the human digestive system
Figure 27
Which of the following will result if X is removed?
A
Lipase is not produced
B
Fats will not be digested
C
Proteins will not be digested
D
Pancreatic juice does not reach the duodenum
YEAR 2004
1
The figure represents a chemical equation for photosynthesis.
Carbon dioxide
+
P
Light
Q
Chlorophyll
What are P and Q?
P
2.
Q
A
Water
Ion
B
Water
Glucose
C
Hydrogen ion
Starch
D
Hydrogen ion
Glucose
The figure shows a "healthy diet" pyramid.
Which level of food needs to be taken the most?
A Level 1
B Level 2
C Level 3
D Level 4
+
Oxygen
3.
The diagram shows a longitudinal section of a villus.
Which of the following nutrients are found in X?
I
II
III
IV
A
B
C
D
4
Glucose
Amino acid
Fat
Vitamin D
I and II only
III and IV only
I, II, and IV only
I, II, III and IV
The following measurements were made during an experiment to determine
the calorific value of bread.
Mass of bread
=2g
Mass of water
= 10 g
Initial water temperature
= 28oC
Final water temperature
= 56oC
What is the calorific value of the bread?
A 140 Jg-1
C
B 280 Jg-1
D
5.
588 J g-1
1 176 J g-1
The diagram shows an experiment on photosynthesis.
Which of the following will increase the rate at which gas bubbles are released in
the experiment?
A Using a 40 W bulb
B Using water bath of 45°C
C Replacing Elodea with Hydrilla
D Using sodium hydrogen carbonate solution 1.0%
YEAR 2005
1.
The diagram shows the structure of a chloroplast seen under an electron
microscope.
Which of the following processes occurs in X?
A Reduction of carbon dioxide by hydrogen
B Dissociation of water molecule by sunlight
C Production of glucose
D Production of starch
2.
The diagram shows the feeding method of organism X
What is the feeding method of organism X?
A Holozoic
C Saprophytic
B Parasitic
D Autotrophic
3.
The diagram shows cross sections of the leaves of four different hibiscus
species. Which of the following leaves A, B, C or D, will produce the highest
rate of photosynthesis?
B
4.
The diagram shows a human digestive system.
Which of the parts A, B , C or D, produces an enzyme that hydrolyses fats?
C
5.
A
B
C
D
6.
Which of the following information is true for both photosynthesis and aerobic
respiration?
Photosynthesis
Aerobic respiration
Cell that carries out the process
Cells with
All types of living cells
chloroplasts
Condition at which process takes
Presence of light
Absence of light
place
Water and carbon
Glucose
Substrate
dioxide
Glucose, oxygen and Carbon dioxide, ethanol
Products
water
and energy
The photograph shows a child suffering from a disease.
Which of the foods A, B, C or D, should be taken often by the child to recover
from the disease?
B
7.
The table shows the types and quantity of food taken by a student in a day.
Types of food
Rice
Butter
Potatoes
Milk
Banana
Chicken
Quantity / g
200
50
100
200
50
100
Energy / kJ per 100g
2 000
3 000
500
300
50
800
The total energy obtained by the student is
A 6 425 kJ
C 7 425 kJ
B 6 650 kJ
D 8 950 kJ
8.
A medical check-up shows that a patient’s pancreas is
damaged and has to be removed
Which of the following should be done by the patient to maintain a normal
blood sugar level?
A Take glucose injections
B Take a balance diet
C Take Insulin and glucagon injections
D Reduce intake of high calorie food
YEAR 2006
1
Diagram 8 shows a child suffering from disease.
The child suffers the disease because of lack of
A
B
C
D
2
Which of the following is true about the enzyme and its function?
A
B
C
D
3
carbohydrate
fibre
protein
vitamin
Enzyme
Rennin
Pepsin
Trypsin
Erepsin
Function
Clots milk
Emulsifies milk
Digests fat
Hydrolyses fat
Table 1 shows the nutrient content of R,S,T and U in milk and butter
Food
Milk
Butter
R
3.0
0.5
Nutrient content (%)
S
T
89.0
4.5
16.5
0.0
U
3.6
6.3
Table 1
Which is represented by R, S, T and U?
A
B
C
D
R
Protein
Water
Carbohydrate
Protein
S
Water
Protein
Fat
Carbohydrate
T
Carbohydrate
Fat
Protein
Water
U
Fat
Carbohydrate
Water
Fat
4
Diagram 9 shows the graph of volume of carbon dioxide taken in or released
by a plant in a forest at different light intensities.
Which of the following is true about the information obtained from the graph?
A.
B.
C.
D.
At point W, the quantity of carbon dioxide released is zero
At point X, the quantity of the intake and the release of carbon
dioxide are equal
At point Y, the quantity of carbon dioxide released is maximum
At point Z, the quantity of the intake and the release of carbon dioxide
are equal
YEAR 2007
1. The following equation shows the process of photosynthesis.
Sunlight
P + Water
Q + R
Chlorophyll
What is represented by P, Q and R ?
A
B
C
D
P
Glucose
Oxygen
Carbon dioxide
Carbon dioxide
Q
Water
Glucose
Energy
Glucose
R
Oxygen
Carbon dioxide
Oxygen
Oxygen
2. Three different food tests were carried out on a food sample.
The observations are shown in Table 2.
Test
Benedict’s test
Biuret test
Iodine test
Observation
Brick red precipitate is formed
No change
Iodine solution turns dark blue
Which of the following is the food sample?
A.
B.
C.
D.
3.
Milk
Biscuit
Fried fish
Meat ball
Which of the following is needed during the light-dependent reaction of
photosynthesis ?
A.
B.
C.
D.
ATP
Water
Hydrogen atom
Carbon dioxide
4. Diagram 8 is a graph showing the effect of light intensity on the rate of
photosynthesis.
Which of the following can be concluded about the rate of photosynthesis
between the
curves J and K ?
A.
B.
C.
D.
It is not influenced by the concentration of carbon dioxide
It is limited by the concentration of carbon dioxide
It is limited by the light intensity
It is not influenced by the temperature
5. Which of the following is an effect of malnutrition?
A.
B.
C.
D.
Dwarfism
Colour blindness
Night blindness
Muscular dystrophy
6. The following are four types of enzymes.




Amylase
Sucrase
Lactase
Maltase
Which nutrient can be hydrolysed by all the four types of enzymes?
A.
B.
C.
D.
Carbohydrate
Minerals salts
Protein
Lipid
YEAR 2008
1. Table 2 shows the nutrient content in 100g of various types of food.
Nutrition content
Food
Protein/
g
Lipid/ g
Carbohydrate /g Calcium
/mg
Iron /mg
White
Bread
Apple
8.0
1.7
54.3
100
1.7
0.3
0
12.0
4
0.3
Butter
0.5
82.5
0
15
0.2
Rice
6.2
1.0
86.8
4
0.4
Eggs
12.3
10.9
0
56
2.1
Table 2
A student bled and fractured his bone during school sport practice.
Based on Table 2, which types of food are suitable for the student for the fast
recovery?
A.
B.
C.
D.
Apple, rice, butter
White bread, eggs, rice
Eggs, apple, butter
White bread, butter, apple
2. Which process occurs only in a liver cell?
A.
B.
C.
D.
Synthesis of a new protoplasm
Repair of damaged tissues
Synthesis of bile
Synthesis of plasma membrane
3. The following statements are about the rate of photosynthesis.
The rate of photosynthesis increases when light intensity becomes higher.
In some plants, the rate of photosynthesis decreases in the middles of a hot
sunny day.
Which of the following explains the above statement?
A.
B.
C.
D.
The palisade cells plasmolyse due to water loss
The enzymes involved in photosynthesis are denatured
The stomatal pores close to reduce the loss of water from the leaves
The chloroplasts in the palisade cells are destroyed by the heat
4. The following data is the result of an experiment to determine the energy value of
a
peanut.
Mass of peanut
0.5g
Mass of water
20 g
Initial temperature of water
25oC
Final temperature of water
45oC
The specific heat capacity of water is 4.2Jg-1 oC-1.
Calculate the energy value of the peanut.
A.
1 680 Jg-1
B.
3 360 Jg-1
C.
7 560 Jg-1
D.
11 760 Jg-1
5. Diagram 6 shows a child with rickets.
Which vitamin is he lacking?
A.
B.
C.
D.
Vitamin B
Vitamin C
Vitamin D
Vitamin E
6. Diagram 7 shows hydrolysis of fats.
What are P, Q and R?
A
B
C
D
P
Amylase
Lipase
Amylase
Lipase
Q
Glucose
Fatty acid
Fructose
Glycerol
R
Fructose
Glycerol
Glucose
Fatty acid
7. Diagram 8 shows a method used to improve the quality and quantity of food
production.
What is the method used?
A.
B.
C.
D.
Aeroponics
Hydroponics
Tissue culture
Plant breeding
CHAPTER 6 : NUTRITION
2003
Section
A
B
C


(3)
(1)
2004
Section
A
B
C
-
2005
Section
A
B
C
-
2006
Section
A
B
C


(6)
(8)
2007
Section
A
B
-
2008
Section
A
B

(8)
YEAR 2003
Section A
1. Figure 3 shows several parts of the human digestive system P, Q, R, S, T and U.
(a) Choose the letter that labels the
part where each of the following
hydrolysis reaction takes place.
(i) Protein
peptides
R
(ii) Starch
maltose
P
[2 marks]
(b) The structure T in Figure 3 has
numerous projections.
Draw and label a longitudinal section of
one of these projections in the space
below.
Epithelial
cell
Lacteal
Blood
capillaries
Lacteal
(c)(i)
State the process that occurs in the projections drawn in (b)(i).
Absorption of digested food
[1 mark]
(ii) State one characteristic of the structure T that will help the process in (c)(i) to
function efficiently
- Large surface area for the absorption of digested food
[1 mark]
(d)
As a doctor you have confirmed that a patient is suffering from a disease.
Organ S of the patient has to be removed.
(i) What explanation would you give to the patient?
In your explanation state the effects of the removal of organ S on enzymes
and hormones, and how these affect the digestion and the level of glucose in
the blood.
- S is pancreas
- Removal of pancreas causes enzyme lipase, amylase, trypsin,
hormone
glucagon and insulin cannot be produced.
- Digestion of starch, peptone, peptide and lipid are inhibited.
- Glucose level in blood cannot be control at a normal range because
excess
glucose cannot be converted to glycogen.
[4 marks]
(ii) What advice can you give to that patient to help him handle health
problems that may arise from the removal of organ S?
[2 marks]
- Reduced intake of food that is rich in starch because there is no
pancreatic amylase to digest starch.
- Reduced intake of sugar because the hormone insulin cannot be
produced anymore.
Section C
1. Table 2 shows a breakfast menu for an adult.
Breakfast Menu
Bread
-
2 slices
Fried eggs
-
2
Jam
-
1 teaspoon
Margarine
-
1 teaspoon
Fresh milk
-
1 glass
Banana
-
2
Table 2
(a) (i) Does the breakfast menu in Table 2 provide a balanced diet for an adult?
Give a reason for your answer.
[2
marks]
- Yes
- Contains all the different classes of food ( carbohydrate, lipid, protein,
vitamin, mineral salts, roughage, water) in the correct proportion.
(ii)
Describe what happens to the end products of digestion of the food eaten
during breakfast in the body cell.
[8
marks]
Menu
Bread/ jam
/ banana
Product of digestion
Hydrolysis of
carbohydrate
produces
monosaccharide /
glucose
-
-
Eggs/ milk
Protein is digested
to form amino acid
-
Fried eggs
Fats/ lipid is
hydrolysed to
produce fatty acid
and glycerol
-
-
Relationship between digestion,
absorption and assimilation
Monosaccharide/ glucose is
absorbed into the blood
capillaries by the villus
Monosaccharide/ glucose is
oxidize to produce energy
Excess glucose is stored as
glycogen in the liver and muscle
cells
amino acid is absorbed into the
blood capillaries by the villus.
Amino acid is used to synthesise
plasma protein
Excess amino acids undergo
deamination to produce urea /
uric acid
fatty acids and glycerol are
absorbed by the lacteal and
transported into the lymphatic
system
Excess will be send to the liver
Mineral
salts and
vitamin
Mineral salts and
vitamin
are released in the
process of
digestion of food
-
-
(b)
and then to the adipose tissue to
be stored as fat
Water soluble vitamin and
mineral salts are absorbed by
the blood capillaries
Fat soluble vitamin are absorbed
into the lacteal
Vitamin and mineral salts play an
important role in the
maintenance of good health
Table 3 shows the result of an analysis of meat-based fast food.
Analysis of content in a fast food





Excess of mineral salt
Excess of fat
Excess of protein
Insufficient fibre
Presence of food preservatives, flavouring and food colouring
Table 3
A teenager frequently consumes meat-based fast food for a long time.
Describe the effects of consuming the meat-based fast food for long periods as
compared to consuming a balanced diet for the same period of time.
[10 marks]
-
Teenager may have problems such as obesity(), constipation(), high
dosage of mineral salts, kidney failure/ kidney stones.
-
Obesity is caused by excessive intake of food. Hence, teenager may
have high blood pressure(), diabetes(), heart disease and
arteriosclerosis()
-
Constipation is caused by lack of fibre(). Teenager may have intestinal
diseases().
-
Excessive intake of mineral salts() will caused poisoning of high
dosage of mineral salts. If mineral salts is taken excessively, cirrhosis
of liver will occur(). The high intake of calcium and phosphorus will
result in the formation of kidney stones (),
-
Excessive intake of protein ()will result in kidney failure(). The
kidney cannot excrete the urea that is formed causing toxin to be
accumulated in the blood(). This can caused death.
-
The use of preservative, seasoning and food colouring () can cause
cancer() because these substances are carcinogenic.
YEAR 2006
Section B
1.
Diagram 6 shows three organisms, P, Q and R.
(a) (i) Describe the type of nutrition in P and Q.
[4 marks]
Organism P
- Autotroph nutrition
- Synthesize/produce its own food from simple inorganic substances
with the help of light
Organism Q
- Heterotroph nutrition
- Obtain its food source / organic substances from the surroundings
(ii) Explain one similarity and four differences between the alimentary canal of Q
and R.
[10
marks]
Similarity:
- Alimentary canal of both Q and R contains bacteria / protozoa or
large surface area or extracellular enzymes
- To digest cellulose into glucose or increase rate of diffusion
Differences:
1. Number of stomach chamber
Explanation
Organism R has 4 stomach chambers; Organism Q has 1 stomach
chamber
2.
Size of the caecum
Explanation
Organism R has a small/short size caecum; Organism Q has a
big/long size caecum
3.
Bacteria / Protozoa
Explanation
At the stomach chamber of organism R, most bacteria/ protozoa are
in the rumen and reticulum; At the stomach chamber of organism
Q, most bacteria/ protozoa are in the caecum.
4.
(b)
The number of times the food passes through the stomach chamber
Explanation
For organism R, the food passes through the stomach chamber
twice;
For organism Q, the food passes through the stomach chamber
once
Constipation, night blindness and anemia are three health problems.
State the cause and suggest the ways to overcome these health problems
from nutritional aspects.
[6 marks]
1. Constipation
- Insufficient amount of fibrous food
- Eat more vegetables / fruit
2. Night blindness
- No/Insufficient vitamin A
- Eat more red carrots / tomatoes
3. Anemia
- Insufficient iron / ferrum nutrient
- Eat more spinach / chicken liver /cow liver
YEAR 2006
Section C
1
Green plants synthesize their food through the process of photosynthesis.
The chemical process of photosynthesis can be summarised as in the
schematic diagram in Diagram 8.
(a)
State the meaning of photosynthesis based on the schematic diagram in
Diagram 8.
[2 marks]
A process whereby a green plant
- produces glucose / starch from carbon dioxide and water
- in the presence of chlorophyll and sunlight
(b)
Starting with water and carbon dioxide as the raw materials, describe how a
green plant produces starch molecules.
[8 marks]
During light reaction stage:
- Chlorophyll absorbs / traps light energy to produce ATP and electrons
- Photolysis of water produce H+ and OH- ions
- H+ ion combines with electron to form hydrogen atom
- Hydrogen and ATP will be used in the dark reaction
During dark reaction stage:
- The process takes place in the absence of light / in dark condition
- CO2 combines with hydrogen to form glucose and water
- Glucose molecules undergo condensation / converted to starch for
storage
- Formation of glucose and starch requires ATP / chemical energy
(formed during light reaction stage)
(c)
It is found that the process of photosynthesis contributes to the balance of
nature. Explain how air pollution may have an effect on photosynthesis and
the balance of nature.
[10 marks]
The importance of photosynthesis:
- Provides food to human being / animals
- Provides / replaces oxygen in the atmosphere
- Helps to maintain the percentage of CO2, / O2 in the atmosphere
The sources of pollution:
- Motor vehicles / burning of fossil fuels
- Urbanisation / quary
Explanation
- Liberates heavy smoke / acidic gas
- Increase particles content in the air
The effect of air pollution:
- Particles accumulate on the leaf surface
- Covers the stomata // reduced O2 + CO2 gas exchange
- Forms heavy / thick smog in the air
- Cuts / reduced light intensity that reached the leaves
Rationalize / Justify the problem:
- Rate of photosynthesis decreases
- Less CO2 is absorbed from atmosphere and less O2 is released
- Facilitates / promotes green house effect / global warming / acid rain.
YEAR 2008
Section B
1 (a)(i) After absorption of nutrients in the small intestine, the undigested
substances in the colon result in the formation of faeces.
Explain the formation of faeces in a human.
- Contents in small intestine that are not absorbed enter the colon/large
intestine
- The contents consists of a mixture of water, fibre, bacteria, dead cells
and bile pigments.
- The contents move slowly along the colon by peristalsis
- Water is reabsorbed from the contents in the colon
- to form faeces /semi solid waste
[4 marks]
(ii) Malnutrition is a condition due to taking an unbalanced diet in which certain
nutrients are lacking, in excess or in the wrong proportions.
Explain the effect on a child who is given insufficient amounts of any two
nutrients of food for a long period of time.
Protein
- A child who is deficient in protein for a long period of time may
suffer from kwashiorkor / marasmus
- protein is needed for normal growth
- lack of protein causes growth of the child to be stunted
Vitamin A
- A child who is deficient in Vitamin A for a long period of time may
suffer from night blindness
- Vitamin A is needed to promote healthy rod cells in the retina
- Lack of vitamin A reduced ability to see in dim light
Vitamin C
- A child who is deficient in Vitamin C for a long period of time may
suffer from scurvy
- Vitamin C is needed for healthy gum and skin
- Lack of vitamin C causes swollen and bleeding gum
Vitamin D
- A child who is deficient in Vitamin D for a long period of time may
suffer from rickets
- Vitamin D is needed for healthy development of bones
- Lack of vitamin D causes bones to become soft and grow irregularly
Calcium
- A child who is deficient in calcium for a long period of time may
suffer from osteoporosis
- Calcium is needed to form strong bones and teeth
- Lack of calcium causes the mass of the bones to become porous and
light
[Any two nutrients : 2 X 3 marks]
[6 marks]
(b) Table 8 shows the food intake by a boy aged 15 years in his daily menu. The
daily energy requirement for him is 12 500 kJ.
Types of food
Quantity taken/g
Energy content/kJ
Rice
400
1600
Potato chips
500
1000
Chicken curry
300
300
Boiled egg
150
630
Butter
50
3000
Milk
280
300
Sausage
300
500
Sardine
150
900
Table 8
(i) Based on Table 8, state the value of energy contained in this daily food intake.
Does the food intake satisfy his daily energy requirement?
- The energy produced from the food taken daily is 8230 kJ
- The energy produced is less than the daily energy requirement
[2 marks]
(ii) This boy takes this menu continuously for a long time.
Explain the consequences to his health.
[8 marks]
The menu is unbalanced diet because :
- Does not contain the 7 classes of food in the appropriate ratio
- Leads to malnutrition
-
Does not contain sufficient dietary fibre / roughage
Leads to constipation
-
Contain high fat
Causes obesity / cardiovascular diseases
-
Contain high protein
Causes gout / increase in an acid uric level in blood
-
Contain high carbohydrate
Causes obesity / diabetes mellitus / high blood sugar level
[8 marks]
CHAPTER 6 : NUTRITION
2005
 (1)
2006
2007
 (1)
2008
ANSWER
YEAR 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
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 50˚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 variable
Food sample/white bread and peanut
How to alter the manipulated variable
Use different food sample i.e white
bread and peanut
Responding variable
Temperature changes/energy value of
food sample
How to determine the responding
variable
Measure and record the increase in
temperature of water by using a
thermometer.
Calculate the energy value using the
given formula
Controlled variable
Mass of food sample.
Air movement and temperature
surrounding the experiment
How to maintain the controlled variable
Use the same mass of each sample
food
Ensure 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
White bread
Peanut
Increase in water temperature
(˚C)
5
11
Energy value (Jg -1)
84.0
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
Rice
Boiled potato
Corn
peanut
Margarine
Palm 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.
Table 1
(3 marks)
Table 2 shows the results of this experiment.
Boiling tube, 60W bulb, retord
stand, ruler, paper clip
10
12
15
20
(b) Record the total number of bubbles released in 5 minutes in the boxes provided
in 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.
Variable
Method to handle the variable
Manipulated variable
Light intensity
Responding variable
Total number of bubbles
released in 5 minutes
Constant variable
The concentration of sodium
hydrogen carbonate solution,
duration of exposure to light
source
Use different distance between light source and
Hydrilla sp. i.e : 60cm, 50cm, 40 cm, 30 cm
Count and record the total number of bubbles
released in 5 minutes
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:
1
Light intensity = Distance between light source and Hydrilla sp.
Light intensity (cm-1)
Distance between light
source and Hydrilla sp.
(cm)
60
Total number of bubbles
released in 5 minutes
0.017
10
50
0.020
12
40
30
0.025
0.033
15
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 bubbles
against the light intensity.
[3 marks]
The total number of
bubbles
x
20
x
15
x
x
10
5
0.01
0.02
0.03
0.04
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 prediction
When 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]