| Date | November 2016 | Marks available | 8 | Reference code | 16N.2.HL.TZ0.8 |
| Level | Higher level | Paper | Paper 2 | Time zone | TZ0 / no time zone |
| Command term | Explain | Question number | 8 | Adapted from | N/A |
Question
In ecosystems, energy is used to convert inorganic compounds into organic matter. Energy enters ecosystems through producers.
Explain the processes by which light energy is converted into chemical energy.
Describe how energy flows through and is used by organisms in ecosystems.
Markscheme
a. plants/producers/autotrophs convert light to chemical energy by photosynthesis
b. chlorophyll/photosynthetic pigments absorb light
c. electrons are excited/raised to higher energy level
d. excited electrons pass along chain of electron carriers
e. energy from electrons used to pump protons across thylakoid membrane/into thylakoid space
f. chemiosmosis/proton gradient used to make ATP
g. ATP synthase generates ATP
h. pigments arranged in photosystems
i. electrons from Photosystem II flow via the electron chain to Photosystem I
j. electrons from Photosystem I are used to reduce NADP
k. ATP and reduced NADP used in the light independent reactions/Calvin cycle
l. carbohydrate/glucose/carbon compounds produced containing energy
Award marking points for any point made on a clearly annotated diagram.
a. producers/plants/autotrophs obtain energy from light/sun/inorganic sources
b. food contains energy / energy passed in the form of food/carbon compounds (along food chains/between trophic levels)
c. consumers obtain energy from other organisms/from previous trophic level
This mark point distinguishes consumers from producers.
d. energy released (in organisms) by (cell) respiration
Reject energy used in respiration.
e. ATP produced
f. energy/ATP used for biosynthesis/movement/active transport/other valid use of ATP
g. less energy available / energy lost at each trophic level
Examiners report
Syllabus sections
- 22M.1.HL.TZ1.31: Which products of the light-dependent reactions are used in the Calvin cycle? A. O2 and...
- 18M.1.HL.TZ2.15: What is reduced by Photosystem I ? A. ADP B. NADP C. NAD D. FAD
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17N.2.HL.TZ0.04b:
Describe the process of photolysis in photosynthesis.
- 20N.3.HL.TZ0.3c: Suggest one other factor that has to be kept constant in all the jars during the experiment.
- 21M.1.HL.TZ1.33: A summary diagram of photosynthesis is shown. Which molecule represents ATP?
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20N.3.HL.TZ0.3a:
State the name of the process which occurs in the chloroplasts of Chlorella, that uses CO2.
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21M.2.HL.TZ1.2c:
Outline how the compounds produced by chloroplasts are distributed throughout the plant.
- 18M.1.HL.TZ1.31: ATP is needed to change products of the carboxylation of ribulose bisphosphate into triose...
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16N.2.HL.TZ0.3a:
Identify the following processes as either anabolism or catabolism by placing a tick (√) in the correct box.
- 16N.1.HL.TZ0.31: The electron micrograph shows part of a plant cell. Where do the light-independent reactions...
- 17M.1.HL.TZ2.13: Which technological advance enabled Calvin to perform his lollipop experiment on the...
- 17N.1.HL.TZ0.30: Which process occurs during the light-dependent reaction of photosynthesis? A. ATP, CO2 and...
- 17M.1.SL.TZ1.1: Which structure found in eukaryotes has a single membrane? A. Nucleus B. Lysosome C....
- 17M.1.HL.TZ2.15: What is used to reduce NADP in the light-dependent reactions of photosynthesis? A....
- 18N.1.HL.TZ0.30: The diagram shows the structure of a chloroplast. Where is chlorophyll located?
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20N.1.HL.TZ0.30:
The diagram shows a section through a thylakoid. Electrons move from X to Y.
[Source: Courtesy Alyse Da Quynh.]
What do the letters X, Y and Z represent?
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18M.2.HL.TZ1.7b:
Outline how plants make use of the different wavelengths of light.
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21N.1.HL.TZ1.32:
A plant is allowed to photosynthesize in an atmosphere containing radioactive 14C. Where in the plant stem would radioactive sugars be found?
[Source: sinhyu/123rf.com.]
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20N.3.HL.TZ0.3b.ii:
Explain the scientific reasoning for your hypothesis.
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21M.2.HL.TZ2.6b:
Describe how the structure of the chloroplast is adapted to its function in photosynthesis.
- 18N.2.HL.TZ0.4e.ii: In some boreal species, Rubisco is down-regulated during the winter months. Describe the role...
- 17N.1.HL.TZ0.29: Which reaction does not cause a net release of energy? A. ADP combines with inorganic...
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21M.2.HL.TZ1.2b:
Compare and contrast mitochondria and chloroplasts in terms of the substrates they use and the products they produce.
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20N.3.HL.TZ0.3b.i:
The colours of the indicator in the jars ranged from yellow to purple after five hours.
Predict the distribution of indicator colours in jars 1 to 9.
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18M.2.HL.TZ1.5b:
Compare and contrast the location of ATP synthase and the movement of protons during aerobic cell respiration and photosynthesis.
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21M.1.HL.TZ2.31:
The Hill reaction occurs when isolated chloroplasts are exposed to sunlight in the presence of DCPIP. DCPIP replaces NADP as the final electron acceptor for the light-dependent reactions of photosynthesis. What are products of the Hill reaction?
A. H2O and ATP
B. ATP and CO2
C. O2 and ATP
D. C6H12O6 and O2
- 21M.1.HL.TZ1.32: Which process does not take place in the stroma of chloroplasts? A. Synthesis of...
- 19M.2.HL.TZ1.7a: Outline the roles of helicase and ligase in DNA replication.
- 19M.2.HL.TZ2.8c: Explain Calvin’s experiment and what was discovered about photosynthesis through his work.
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21M.2.HL.TZ2.6a:
Explain the role of hydrogen ions used in photosynthesis.
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21N.2.HL.TZ0.7c:
Explain how the light-independent reactions of photosynthesis rely on the light-dependent reactions.
- 18M.2.HL.TZ1.5c: Using the table, distinguish between the production of ATP, use of oxygen and release of CO2...
- 21N.1.HL.TZ1.31: The diagram shows some of the intermediate compounds produced during the Calvin cycle. At...
