Limiting Factors Question Booklet
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Unit 4- Woodford County High School
1.
The graph shows the effect of different conditions on the rate of photosynthesis.
25°C 0.4% CO 2
Rate of
photosynthesis
B
15°C 0.4% CO 2
25°C 0.01% CO 2
A
Light intensity
(a)
(i)
Name the factor which is limiting photosynthesis at A.
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(1)
(ii)
Give a reason for your answer.
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(1)
(b)
Carbon dioxide is limiting the rate of photosynthesis at B. How does the graph
show this?
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(1)
(c)
A commercial grower is considering increasing the temperature in a glasshouse
during the winter to 25 °C. What would the grower need to consider before
deciding to do this?
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(3)(Total 6 marks)
Unit 4- Woodford County High School
2.
An investigation was carried out to find the effect of increasing carbon dioxide
concentration on the rate of photosynthesis in a particular type of plant. The graph shows
the results.
Rate of
Photosynthesis
A
B
C
Carbon dioxide concentration
(a)
(i)
In this investigation, temperature was kept constant. Explain why.
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(1)
(ii)
Suggest suitable units for measuring the rate of photosynthesis in this
investigation.
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(2)
(b)
(i)
Give the evidence from the graph that carbon dioxide is limiting the rate of
photosynthesis between A and B.
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(1)
(ii)
Explain the shape of the curve between B and C.
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Unit 4- Woodford County High School
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(2)
(Total 6 marks)
3.
An investigation was carried out into the effect of carbon dioxide concentration and light
intensity on the rate of photosynthesis in a species of plant.
(a)
The temperature was kept constant during this investigation. Explain why.
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(2)
(b)
The table shows the effect of increasing carbon dioxide concentration on the rate
of photosynthesis in maize.
Carbon dioxide
concentration / arbitrary units
Rate of photosynthesis / arbitrary
units
30
10
60
20
100
30
150
40
230
50
300
60
400
60
Describe and explain the effect of increasing carbon dioxide concentration on the
rate of photosynthesis.
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(3)
(Total 5 marks)
Mark Scheme
1.
(a)
(i)
Light intensity;
(ii)
As light intensity increases, so does the rate of photosynthesis;
Unit 4- Woodford County High School
1
1
(b)
Reference to 25 °C 4% CO2 line – rate of photosynthesis higher;
1
(c)
Whether light intensity will be high enough;
Whether CO2 levels will be high enough;
Cost of additional heat;
Whether increased yield will offset costs involved;
max 3
[6]
2.
(a)
(i)
(ii)
(b)
temperature also affects photosynthesis/ rate of reaction; need to
ensure the effect of only one variable is being observed;
1
CO2 used/ O2 produced/ sugar produced/increase in mass;
per unit of time;
accept any volume or mass unit; per time unit;)
(allow one mark for indicator of photosynthesis – second
mark is for time element)
2
(i)
as carbon dioxide increases, rate of photosynthesis increases;
1
(ii)
carbon dioxide not limiting photosynthesis;
another factor/named factor limiting;
explanation for named factor;
2 max
[6]
3.
(a)
(b)
Temperature affects photosynthesis; Affects enzyme activity;
So that any change in photosynthesis rate is result of
carbon dioxide/light intensity;
Carbon dioxide increases rate of photosynthesis;
Up to max;
Something else/correct suggestion is a limiting factor;
max 2
3
[5]
Unit 4- Woodford County High School