MODULE 2: QUESTIONS
UNIT 1
 The large number of tubes provides a large surface area through which
substances can diffuse.
 A fluid, known as the dialysis fluid, flows around the tubes in the opposite
direction to the blood.
 This forms a counter-current system that makes the maximum exchange of
substances between the blood and the dialysis fluid possible.
The diagram below is a representation of PHOTOSYNTHESIS.
QUESTION 1
by-product X
 The dialysis fluid contains all the important non-protein components of blood
plasma in their normal concentrations but wastes such as urea, uric acid and
creatinine are absent.
 Any substance in the blood plasma that has a lower concentration than normal is
replenished by diffusion from the dialysis fluid.
 Because the dialysis fluid does not contain any nitrogenous wastes, a steep
concentration gradient is formed.
 The waste products diffuse down a concentration gradient from a high
concentration in the blood to a low concentration in the dialysis fluid.
The dialysis fluid must be replaced continuously
to maintain the correct concentrations.
 The dialysis fluid flows continuously through the kidney machine to remove any
waste substances that diffuse into it from the blood.
carbohydrate Y
W
2
Phase A
energy-rich
H-atoms
Phase B
ATP
1.1 Define the term photosynthesis.
1.2 In which organelle does photosynthesis occur?
1.3 Identify the phases which are marked A and B respectively.
1.4 In which part of the organelle mentioned in Question 1.2, does A and B
take place, respectively?
1.5 Identify the TWO raw materials numbered 1 and 2 respectively.
1.6 Identify the by-product marked X.
1.7 Identify the inorganic substance, marked W, that is essential for phase B.
1.8 Identify the carbohydrate product marked Y.
1.9 In what form is product Y stored in plants?
QUESTION 2
Discuss the importance of photosynthesis for life on earth.
 The blood circulates through the kidney machine a few times during
one treatment.
QUESTION 3
 One treatment can last up to 6 hours.
3.2 What is the purpose of a greenhouse?
 The purified blood leaves the kidney machine and flows through a filter that traps
air bubbles so that they cannot flow back into the vein of the patient's arm.
3.3 Describe the role of the THREE factors, mentioned in Question 3.1, in a
greenhouse system.
3.4 Identify the factors numbered 1 and 2 in the graphs below that influence the
rate of photosynthesis.

Rate of
photosynthesis
 Although dialysis can keep a person with renal failure alive, it is not a long-term
solution. Dialysis is a time-consuming and unpleasant process.
Rate of
photosynthesis
Kidney transplant
3.1 Name and discuss THREE factors that influence the rate of photosynthesis.
A better option is a kidney transplant, where the diseased kidney of the
patient is removed and replaced by a healthy donor kidney.
Factor 1
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Factor 2
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UNIT 1: PHOTOSYNTHESIS
 Any substance that occurs in excess in the blood plasma diffuses from the blood
to the dialysis fluid until the concentration is normal.
1
2
QUESTIONS
 The membranes are permeable to all blood components except blood cells
and proteins.
QUESTIONS
2
QUESTION 4
During an investigation three leaves of the same plant are exposed to certain conditions
and are then tested for the presence of starch.
Leaf
Raw materials present
1
carbon dioxide, water, light
2
water, light
3
carbon dioxide, water
QUESTION 7
In an investigation to determine whether two factors are essential for photosynthesis to
occur successfully, the accompanying variegated leaf was used. It was partially covered
with foil. The destarched plant was placed in the sun for a few hours and then tested for
the presence of starch.
A
B
4.1 Why are the leaves tested for the presence of starch?
C
green
part of
leaf
tin foil
4.2 Which leaf will show a positive result after the starch test?
white part
of leaf
4.3 Give a reason for your answer in Question 4.2.
4.4 Write down an equation for photosynthesis that includes all raw materials,
environmental factors and products.
7.1 Why is the plant first destarched?
QUESTION 5
7.2 How is a plant destarched?
Study the practical investigation below where a leaf is tested for the presence of starch
and answer the questions that follow.
7.3 Which TWO factors were simultaneously tested for?
B
A
C
E
D
7.4 Formulate a hypothesis for this investigation.
7.5 Draw a neat diagram that shows the result of this investigation. Show the colour
changes after the starch test on the various parts marked A, B and C on the leaf.
7.6 How can one improve the reliability and validity of these results?
7.7 What substance gives plant leaves their green colour?
5.2 At C the leaf is placed in alcohol. What is the purpose of the alcohol?
7.8 When a rolled-up hosepipe, that was lying on the lawn for a few days, is lifted
from the lawn, the grass underneath the hosepipe is not green, but yellow/white.
Why does this happen?
5.3 When the leaf is placed in alcohol the flame is turned down. Give a reason
why this is essential.
QUESTION 8
5.1 At B the leaf is placed in boiling water. State TWO reasons for this step.
5.4 Why will alcohol keep on boiling even after the flame was turned down?
A practical investigation was set up as illustrated below. The plants were exposed to
sunlight for a few hours after being destarched. A leaf of each plant was then tested
for starch.
UNIT 1: PHOTOSYNTHESIS
5.5 What chemical reagent is used at E to test for the presence of starch?
5.6 What colour change will take place if the leaf tests positively for starch?
QUESTION 6
soda lime
The following diagrams (A, B, C and D) show practical investigations, or parts of practical
investigations. Write down the AIM of each practical investigation.
A
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D
C
B
green
leaf
ethanol
green part
of leaf
white part
of leaf
tin foil
tin foil
cotton wool
potassium
hydroxide
solution
A
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sodium hydroxide
solution
B
sodium bicarbonate
solution
8.7
Explain your observations for plant A and B, respectively.
Formulate a hypothesis for this practical investigation.
Why are two sets of apparatus, an experiment and a control, used?
Which set up (A or B) represents the control?
Identify the independent variable in this investigation.
State ONE constant/fixed variable from the environment that is present in
this investigation.
What is the function of each of the following in this investigation:
8.7.1 sodium hydroxide solution
8.7.2
QUESTION 11
A practical investigation was conducted to determine the effect of water temperature on the
rate of photosynthesis of a water plant, using the apparatus shown below. The number of
bubbles of gas released per minute was measured at a number of different temperatures.
The results are illustrated below.
50
45
sodium bicarbonate solution
8.7.3 soda lime
8.8 Why will it make the investigation more reliable if one isolates/covers the soil
in the pots?
8.9 What conclusion can you draw from this investigation?
8.10 Is your hypothesis, as stated in 8.3, accepted or rejected once the investigation
is completed?
2
QUESTIONS
8.2
8.3
8.4.1
8.4.2
8.5
8.6
Record your observations of a leaf from plant A and B, respectively AFTER
the starch test.
Number of gas bubbles
8.1
40
35
30
25
20
15
10
5
0
0
QUESTION 9
5
10 15
20
25 30 35 40 45
50
Temperature of water (ºC)
Plants require carbon dioxide, water and light to produce sugar during photosynthesis.
Assume a plant requires 4 units water, 4 units carbon dioxide and 10 units of light to
produce 2 sugar units. Study the following table of data from five plants (1 - 5) and answer
the questions that follow.
11.1 What is the name of the gas that is released during photosynthesis?
11.2 At what temperature is the rate of photosynthesis the highest?
11.3 How many gas bubbles are produced at 38ºC?
9.2
9.3
9.4
9.5
Units water
Units CO2
Units light
1
16
16
20
2
16
12
30
3
20
16
20
4
20
20
40
5
16
40
16
Draw a bar graph to compare the number of sugar units produced by each of
the five plants.
Which plant produced the most sugar?
If plant 5 received another 14 units of light, how many units of sugar will it be
able to produce?
How many more units of light does plant 4 require to produce 10 units of sugar?
Which factor prevents plant 1 from producing more sugar?
QUESTION 10
Describe the process of photosynthesis from the moment light is absorbed until
carbohydrates are formed.
11.4 Explain the sudden drop in the rate of photosynthesis after the maximum
point was reached.
QUESTION 12
A tomato farmer was able to produce crops in greenhouses which were heated to
between 15°C and 22°C. In addition, the carbon dioxide level was increased from the
normal 0,03% to 0,1%.
12.1 State ONE way in which the farmer could have enriched the air inside the
greenhouse with carbon dioxide, without burning any fuel.
12.2 Explain how increasing the carbon dioxide levels up to 0,1% can lead to an
increased production of tomatoes.
12.3 Name TWO other factors which might have to be increased to obtain an even
greater yield when the carbon dioxide level is increased to above 0,1%.
12.4 The additional carbon dioxide is only provided during the daylight hours.
Suggest a reason for this.
12.5 Predict what would happen if the carbon dioxide concentration within the
greenhouse is increased to 0,5% for between 10 to 15 days if all other factors
are kept constant.
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UNIT 1: PHOTOSYNTHESIS
9.1
Plant
QUESTION 13
A practical investigation was conducted to determine the relationship between light
intensity and the release and uptake of carbon dioxide by the leaves of a plant.
The results are indicated in the graph below.
1.1 Name FIVE main stages of animal nutrition and briefly state what is meant
by each process.
8
1.2 Give THREE reasons why food is essential and indicate the food groups
that are responsible.
7
6
5
QUESTION 2
4
2.1
Define the term heterotroph.
2.2
Name the three groups into which animals are classified, according to the food
they eat.
3
2
1
CO2 produced
3
(mg/50 cm )
UNIT 2
QUESTION 1
The relationship between light intensity
and the release and uptake of carbon dioxide
CO2 taken up
3
(mg/50 cm )
QUESTIONS
2
0
-1
5
10
15
20
25 30
35
40
45
50
2.3 Construct a table to compare herbivores, carnivores and omnivores under the
following headings:
2.3.1 example
-2
2.3.2 type of food
Light intensity (arbitrary units)
2.3.3 amount and energy value of food intake
2.3.4 adaptations of teeth
13.1 Within which range of light intensities is carbon dioxide released?
13.2 Name the process that uses carbon dioxide in the leaves.
13.3 Why is the most carbon dioxide released at a light intensity of zero (0) units?
Study the diagram of the human digestive system
and answer the questions that follow.
13.4 How much carbon dioxide is absorbed by the leaves at a light intensity of 20 units?
3.1 Identify the labels numbered 1 to 12.
13.5 When the light intensity is approximately 2 units, there is no net change in the
concentration of carbon dioxide surrounding the plant. Give an explanation for this.
UNIT 2: ANIMAL NUTRITION
QUESTION 3
13.6 At a light intensity of above 25 units, the amount of carbon dioxide absorbed
remains the same. Provide an explanation for this observation.
13.7 Name TWO external factors that need to be kept constant during the investigation.
3.2 Make a neat, labelled diagram of a
cross section through the part numbered 7.
1
3.3 Name the THREE pairs of salivary glands.
3.4 What are the muscle contractions that
occur in the part numbered 1 called?
3.5 What is the purpose of the type of muscle
contraction mentioned in Question 3.4?
3.6 Which digestive juice is secreted by the
part numbered 4?
2
4
3
5
6
7
10
8
9
11
12
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