1011-Level O Biology Basic Questions
[Page 1 of 11]
Chapter 16: Photosynthesis
Part A
1-
Define the terms
a)
action spectrum
b)
absorption spectrum
2-
Explain what happens to chlorophyll when it is photoactivated.
3-
Explain why is it advantageous for plants to have more than one type of photosynthetic pigments.
4-
Discuss the roles of pigments & carrier molecules in light-dependant stage of photosynthesis.
5-
Describe the fixation of carbon dioxide in the light-independent stage of photosynthesis.
6-
Explain how
a)
light energy from the Sun, and
b)
carbon dioxide from the air,
pass to & are used by the chloroplast during photosynthesis.
7-
Give an account of the structure, function & distribution of chloroplasts in leaves.
8-
Describe how the light energy of the Sun is converted to chemical energy in green plants.
9-
Explain what is meant by the term “limiting factor”. Illustrate your answer by reference to the effects of
temperature on photosynthesis.
To answer the following questions, you will need to bring together information from other areas of your
course as well as from this chapter.
10- a)
Compare the structures of chloroplasts & mitochondria with the structure of a typical prokaryotic
cell.
b)
11- a)
b)
Describe the roles of membranes in chloroplast function.
Describe the functions of xylem & phloem in photosynthesis in a leaf.
Relate these functions to the structure of the two tissues.
12- With reference to enzyme function, explain the effect on the rate of photosynthesis of:
a)
increasing the concentration of carbon dioxide
b)
increasing the temperature.
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Part B
1-
2-
Name the following processes which occur in photosynthesis:
a)
The splitting of water molecules using light energy.
b)
The formation of ATP using energy from electrons excited by light.
c)
The reactions in photosynthesis consisting of photolysis & photophosphorylation.
Read the summary of photosynthesis & then write a list of the most appropriate word(s) to complete the
passage.
a)
Photosynthesis involves building up complex organic compounds from --------, --------compounds. This kind of food production is called ----------- nutrition. Light energy is absorbed
by -------------- molecules, causing -------------- to be displaced. The most effective parts of white
light are the -------------- & ------------- colours. The light-dependant reactions occur in the ------------ of the chloroplasts. The gas ----------- is released when ------------ is split. --------------- & ------------ are produced. These are used in the light-independent reactions to reduce the gas ----------.
The hexose sugar ----------- is produced.
b)
In the light-independent stage the molecules of carbon dioxide are accepted by --------.
The products --------- & --------- from the light-dependant stage are needed to form -------.
The compound can then be converted into a ------------- sugar.
3-
a)
b)
4-
How many turns of the Calvin cycle are necessary to produce one molecule of:
i)
ribulose biphosphate
ii)
glucose
Give the number of C atoms which one molecule of each of the following contains:
i)
carbon dioxide
ii)
triose phosphate
iii)
ribulose phosphate
iv)
hexose
Indicate the correct answer to the following:
a)
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The coenzyme used in photosynthesis is:
A-
NAD
B-
ATP
C-
FAD
D-
NADP
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b)
c)
d)
e)
f)
g)
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[Page 3 of 11]
Electrons from non-cyclic phosphorylation pass into the dark reaction via:
A-
ATP
B-
NADPH2
C-
hydroxyl ions
D-
H+ ions
Oxygen is evolved during photosynthesis from:
A-
the light-dependant stage when water is split
B-
the light-dependant stage when carbon dioxide is split
C-
the light-independent stage when water is split
D-
the light-independent stage when carbon dioxide is split
The pigment in leaves appears green because:
A-
the green wavelengths of light are reflected
B-
the green wavelengths of light are absorbed
C-
the blue & red wavelengths of light are reflected
D-
the blue & red wavelengths of light are absorbed
The metal element found in chlorophyll is
A-
iron
B-
hydrogen
C-
manganese
D-
magnesium
The Calvin cycle involves:
A-
the splitting of water to release oxygen
B-
the reduction of CO2 to form carbohydrate
C-
the phosphorylation of ADP to ATP
D-
the reduction of NADP to NADPH + H+
The carbon acceptor molecule in the light-independent reaction is:
A-
phosphoglyceric acid
B-
triose phosphate
C-
ribulose biphosphate
D-
hexose sugar
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5-
The graph above shows the changes in relative amounts of photosynthetic intermediates found in the
chloroplast during periods of light & dark conditions.
What information does this give you about the part played by ribulose biphosphate and
glycerate 3 phosphate during photosynthesis?
6-
The graph shows the percentage of light, of different wavelengths, absorbed by an alcohol solution of
chlorophyll a, in the laboratory.
The table below shows how effective these wavelengths are in driving photosynthesis in intact plants. The
most efficient wavelength is given a value of 100%.
Wavelength
(nm)
Percentage
efficiency
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400
450
500
550
600
650
700
84
96
64
40
58
80
28
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[Page 5 of 11]
a)
Using the right-hand axis, plot the data on the graph.
b)
Estimate which of the 50 nm ranges would contain the most effective wavelength.
c)
What is the name given to the graph you have plotted?
d)
i)
At what wavelength does the difference between the two plots have the greatest value?
ii)
Suggest an explanation for this difference.
e)
Suggest how you might set up an experiment to obtain the data in the table.
f)
From the information given at the beginning of the question, suggest why a comparison of the two
graphs might lead to unreliable biological conclusions.
7-
a)
Research biologists have discovered that some photosynthetic blue-green algae have an important
enzyme, nitrogenase which is easily damaged by oxygen. Some types of the microorganism can
protect the enzyme by encasing it in cells which lack enzymes for the photosystem in
photosynthesis which splits water. These cells have thick walls.
b)
i)
Explain how these adaptations will protect the nitrogenase.
ii)
Which product of the light-dependant reactions will these cells be able to produce?
Describe how isotopes can be used to show that the oxygen released in photosynthesis originates
from the water & not from the carbon dioxide.
8-
The graph above shows the changes in relative amounts of photosynthetic intermediates found in the
chloroplast during periods of light & dark conditions.
What information does this give you about the part played by ribulose biphosphate and
glycerate 3 phosphate during photosynthesis?
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9-
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The diagram below shows the light-independent reaction of photosynthesis.
a)
This cycle of reactions is often named after its discoverer. Give this name.
b)
Name the molecules which enter the cycle at R & T.
c)
Give the full names of the molecules S & U.
d)
What is produced at V?
e)
i)
Name the reducing agent which is used up in the cycle.
ii)
Name the photosynthetic stage which produces this agent.
10- The diagram below shows some of the processes which occur in the light-independent reaction of
photosynthesis.
a)
Name the substances represented by the letters X & Y.
b)
State the origin of the NADPH+H+ & the ATP used in the light-independent reaction.
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11- a)
i)
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Use the diagram of an electron micrograph of a chloroplast to name structures X, Y & Z.
Use the letters on the diagram to identify:
ii) Where the light-dependent reactions take place.
iii) Where the light-independent reactions occur.
b)
12- a)
i)
Describe the arrangement of chlorophyll within the chloroplast.
ii)
Suggest why it is arranged in this way.
Below is a diagram of a transverse section through a leaf.
Name the cells A, B and C.
b)
Name three types of cells in the leaf which contain chloroplasts.
c)
Name two environmental factors which may cause E to close.
d)
Describe variations that would occur in oxygen concentrations at point D throughout a normal
24-hour period. Explain why these variations occur.
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13- The graph below shows how the rate of photosynthesis varies when a plant is grown under different
environmental conditions. Use the information on the graph to answer the following questions.
a)
Describe the way the rate of photosynthesis varies as light intensity increases for a plant grown in
an atmosphere containing 0.04% CO2 at 20°C.
b)
Describe the effect of increasing the temperature from 20°C to 30°C for plants grown in an
atmosphere containing 0.04% CO2.
c)
If the plant in this experiment was a crop plant grown in a glasshouse, explain the optimum
environmental conditions of light & temperature that should be supplied to make it worthwhile to
increase the CO2 content of the glasshouse atmosphere.
d)
Suggest how the CO2 content of the atmosphere & the temperature could be increased at the same
time.
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Part C
1-
The part played by chlorophyll in photosynthesis was investigated by Engelmann. He put filaments of
green algae on three microscope slides and added a suspension of motile, oxygen-requiring bacteria to
each. Each slide was then placed in a small chamber from which was excluded. Engelmann placed each
of these chambers in different light conditions for several hours & then examined them.
The results are shown in the diagram.
a)
How does the distribution of bacteria on slide A provide evidence that chlorophyll is necessary for
photosynthesis?
b)
One explanation for the results was that bacteria were attracted towards the light. What evidence
from the results disproves the idea?
c)
2-
Suggest an explanation for the result on slide C.
Calvin investigated the pathway by which CO2 is converted to organic compounds during
photosynthesis. He used the apparatus shown in the diagram shown below.
The apparatus contained cells of a unicellular algae. While the apparatus was in a dark room, Calvin
supplied the algal cells with CO2 containing radioactive carbon. The contents of the apparatus were
thoroughly mixed, then a light was switched on. At 5 second intervals he released a few of the cells into
hot alcohol, which killed the cells very quickly.
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a)
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i)
Why is the part of the apparatus containing the algal cells thin?
ii)
How would it be possible to prevent the light source from heating the algal cells?
iii)
Suggest why it was necessary for the algal cells to be killed very quickly?
Calvin homogenized the killed algal cells & carried out two-way paper chromatography. This technique
involves running the chromatogram with one solvent, then turning the paper through 90° & running it with a
different solvent. By using this technique, Calvin was able to investigate the chromatogram he obtained. The
spots are those containing radioactive compounds.
b)
Suggest how the compound in each spot might be identified.
c)
i)
Name the compound first formed in the pathway in which CO2 is converted into an organic
compound.
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ii)
Which of the spots W, X, Y or Z contained this compound?
iii)
Explain your answer to ii.
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3-
[Page 11 of 11]
A shoot of Canadian pond weed was placed in the apparatus shown below.
The rate of photosynthesis was measured.
a)
What is the purpose of X?
b)
Why has sodium hydrogen carbonate been added to the pond water?
c)
What two precautions would you use to make your results more reliable?
d)
If you collected a gas bubble of length 9mm in 10 minutes, how would you calculate the volume
of gas produced per hour if conditions remained constant?
The diameter of the capillary is 2mm. Show your working.
e)
What is the gas produced in this experiment?
f)
Is the gas collected a direct measure of photosynthesis?
g)
What is the function of the syringe?
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