4.4.1
Photosynthesis
Describe the affect that light intensity has on the
rate of photosynthesis.
Describe the affect that temperature has on the rate of
photosynthesis.
Write the word equation for photosynthesis.
________ + __________  __________ + ___________
Describe the affect that the amount of carbon dioxide has on
the rate of photosynthesis.
Write a balanced symbol equation for photosynthesis.
________ + __________  __________ + ___________
Describe where in the
leaf photosynthesis
occurs and the chemicals
used for converting
light.
Explain why
photosynthesis is
described as an
endothermic reaction.
Describe the affect that the amount of chlorophyll has on the
rate of photosynthesis.
What is meant by the term ‘limiting factor’ and how does this
apply to the rate of photosynthesis.
What is the
name of the
equipment used
in the image?
Describe how this equipment can be used to measure the rate of photosynthesis.
Explain why a plant grower must be aware of these
limiting factors when considering the cost of growing
plants.
Glucose is an important nutrient for plants and is used
in many different ways. Give the five ways that glucose
is used in a plant and it is important.
1.
RSEPOANTOIR –
How is this useful?
2. CHRATS –
How is this useful?
Describe how plants gain nitrates from the soil and why
they are important.
3. ATF & LIO –
How are these useful?
4. LLLCESOEU –
How is this useful?
Describe how we would test for the presence of
glucose, proteins and starch in a plant..
State the two other limiting factors in this exam question
other than light intensity.
5. NAMIO SICDA –
How are they useful?
State the ideal conditions for a lettuce plant to grow using
the above exam question.
1.
Calculate
distance.
2. Calculate
equation:
3. Calculate
equation:
the mean amount of oxygen produced for each
What meant by the term ‘inverse square law’?
the rate of photosynthesis using the following
Rate = 1/Time
the light intensity by using the following
Light Intensity = 1 / distance2
Amount of oxygen (mm2)
Distance of pondweed
from the lamp (cm)
1
2
3
10
38
40
39
20
37
36
39
30
18
20
22
40
6
14
9
50
3
8
4
Mean amount of
oxygen (mm2)
Rate of
Photosynthesis
Light Intensity
Use the
information in this
table to plot a
graph showing how
the rate of
photosynthesis is
affected by light
intensity.
What is the independent variable in this
investigation?
What is the dependent variable in this
investigation?
State the two other limiting factors in this exam question
other than light intensity.
State the ideal conditions for a lettuce plant to grow using
the above exam question.
What are the control variables in this
investigation?
4.4.1
Photosynthesis
Describe the affect that light intensity has on the
rate of photosynthesis.
Light is needed for photosynthesis to occur and so
the more light the plant has, the rate of
photosynthesis will increase.
Write the word equation for photosynthesis.
Describe the affect that the amount of carbon dioxide has on
the rate of photosynthesis.
Carbon Dioxide + Water  Oxygen + Glucose
Carbon dioxide is needed for photosynthesis to occur. The more
carbon dioxide there is, more can be converted to oxygen and
glucose in photosynthesis.
Write a balanced symbol equation for photosynthesis.
6CO2 + 6H2O  6O2 + C6H12O6
Describe where in the
leaf photosynthesis
occurs and the chemicals
used for converting
light.
Boiling Tube
Describe the affect that the amount of chlorophyll has on the
rate of photosynthesis.
Explain why
photosynthesis is
described as an
endothermic reaction.
Photosynthesis is
described as an
endothermic reaction
because it takes in heat
from the surroundings.
Photosynthesis occurs in
the chloroplasts of a
leaf and chlorophyll is
the chemical that
absorbs light.
Water
Pondweed
Beaker
Lamp
Describe the affect that temperature has on the rate of
photosynthesis.
A higher temperature will initially increase the rate of
photosynthesis due to having more kinetic energy but will
eventually decrease as enzymes needed will denature. Lower
temperatures will mean the molecules have less kinetic energy
for the reaction to occur.
What is the
name of the
equipment used
in the image?
The more chlorophyll found in a plant, the higher the rate of
photosynthesis.
x
What is meant by the term ‘limiting factor’ and how does this
apply to the rate of photosynthesis.
x
x
x
10
20
30
40
Distance in cm
x
50
A limiting factor is a factor that limits the rate of a reaction
from increasing any further due even though other factors
may increase. This applied to photosynthesis due to some
factors may be increased but without increasing other factors
the rate of photosynthesis may remain the same.
Describe how this equipment can be used to measure the rate of photosynthesis.
You can measure the rate of photosynthesis by changing the distance the pondweed is to the lamp and measuring the volume of gas (oxygen)
produced in 1 minute.
Stand
Explain why a plant grower must be aware of these
limiting factors when considering the cost of growing
plants.
Glucose is an important nutrient for plants and is used
in many different ways. Give the five ways that glucose
is used in a plant and it is important.
Limiting factors are important in the economics of
enhancing the conditions in greenhouses to gain the
maximum rate of photosynthesis while still maintaining
profit.
1.
RSEPOANTOIR – RESPIRATION
How is this useful?
Produces energy by breaking down glucose made in
photosynthesis.
2. CHRATS – STARCH
How is this useful?
Starch is a store of energy for the plants.
Describe how plants gain nitrates from the soil and why
they are important.
Plants gain nitrate from the soil by the process of
active transport. They require nitrate for the synthesis
of proteins. These proteins are needed for the plant to
grow and repair.
3. ATF & LIO – FAT & OIL
How are these useful?
These are also a store of energy.
4. LLLCESOEU – CELLULOSE
How is this useful?
Describe how we would test for the presence of
glucose, proteins and starch in a plant.
Cellulose is used in the cell wall to give the structure
strength for protection.
Glucose = Benedict’s Reagent – Blue to Brick Red
5. NAMIO SICDA – AMINO ACIDS
Proteins = Biuret Reagent – Blue to Purple
How are they useful?
Starch = Iodine Reagent – Orange to Blue/Black
Amino acids are used to build proteins needed for
growth and repair.
State the two other limiting factors in this exam question
other than light intensity.
Temperature and carbon dioxide levels
State the ideal conditions for a lettuce plant to grow using
the above exam question.
4% CO2 and 25 degrees.
1.
Calculate
distance.
2. Calculate
equation:
3. Calculate
equation:
the mean amount of oxygen produced for each
What meant by the term ‘inverse square law’?
the rate of photosynthesis using the following
Rate = 1/Time (30s)
the light intensity by using the following
Light Intensity = 1 / distance2
There is an inverse relationship between distance and light
intensity - as the distance increases, light
intensity decreases. This is because as the distance away
from a light source increases, light energy becomes spread
over a wider area.
Amount of oxygen (mm2)
Distance of pondweed
from the lamp (cm)
1
2
3
Mean amount of
oxygen (mm2)
Rate of
Photosynthesis
10
38
40
39
39
1.3
0.01
20
37
36
39
37
1.2
0.0025
30
18
20
22
20
0.7
0.0011
40
6
14
9
10
0.3
0.000625
50
3
8
4
5
0.17
1.4
X
State the two other limiting factors in this exam question
other than light intensity.
State the ideal conditions for a lettuce plant to grow using
the above exam question.
Rate of Photosynthesis
1.2
X
0.8
0.6
Amount of pondweed
Amount of water
LED bulb – Temperature
Species of pondweed
Time taken to collect the oxygen.
0.4
X
X
0.0005
What is the independent variable in this
investigation? Distance of the pondweed
from the lamp (Light intensity)
What are the control variables in this
investigation?
X
0
0.0001
0.0004
Use the
information in this
table to plot a
graph showing how
the rate of
photosynthesis is
affected by light
intensity.
What is the dependent variable in this
investigation? Number of bubbles in 30
seconds (amount of oxygen)
1
0.2
Light Intensity
0.001
0.005
Light Intensity
0.01