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13. Photosynthesis
A section of Biology, 9700
Listing 10 of 183 questions
Photosynthesis is an energy transfer process that takes place in chloroplasts of plant cells. shows a diagram of a chloroplast. A B C D not to scale Using the letters A, B, C or D, identify the structure that: • contains genes that code for some of the enzymes used in photosynthesis • is the site of synthesis of some of the enzymes used in photosynthesis. Explain how grana are adapted for their specific role in photosynthesis. An experiment was carried out to investigate the effect of changing light conditions on the pH of the chloroplast stroma. Scientists followed pH changes in chloroplast stroma using fluorescent chemicals that can be used as pH indicators. • Chloroplasts were isolated from cells. • A suspension of chloroplasts was prepared and kept in the dark for 180 seconds. • The chloroplasts were exposed to a period of light of fixed intensity for 240 seconds, then returned to dark conditions. • The pH of chloroplast stroma was continuously measured and recorded. shows the results of this experiment. 7.2 7.3 7.4 7.5 7.6 7.7 time / s pH of chloroplast stroma dark dark light Describe the results shown in . Discuss how the results in support that chemiosmosis occurs during photophosphorylation.
9700_w22_qp_42
THEORY
2022
Paper 4, Variant 2
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Photosynthesis is an important energy transfer process. Name one chloroplast pigment. Explain the relationship between the absorption spectrum of the main chloroplast pigments in a species of plant and the action spectrum for photosynthesis for that species. Explain why temperature can be a limiting factor of photosynthesis. Outline how the light-independent stage of photosynthesis leads to the production of carbohydrates such as starch in plant leaves.
9700_w22_qp_43
THEORY
2022
Paper 4, Variant 3
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Chloroplasts carry out photosynthesis. shows some structural features of a chloroplast and some processes that occur within it. CO2 product D H2O product B stroma light cycle C chloroplast envelope components A make up granum Identify the structures labelled A in . A Explain how the structure and appearance of the granum, and the components labelled A, relate to their function. Identify the metabolic pathway labelled cycle C in . C Explain why pathway C is described as a cycle. Identify the products of photosynthesis labelled B and D in . B D Suggest and explain the importance of glucose and the product labelled B in to ecosystems.
9700_w23_qp_41
THEORY
2023
Paper 4, Variant 1
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Chloroplasts carry out photosynthesis. shows some structural features of a chloroplast and some processes that occur within it. CO2 product D H2O product B stroma light cycle C chloroplast envelope components A make up granum Identify the structures labelled A in . A Explain how the structure and appearance of the granum, and the components labelled A, relate to their function. Identify the metabolic pathway labelled cycle C in . C Explain why pathway C is described as a cycle. Identify the products of photosynthesis labelled B and D in . B D Suggest and explain the importance of glucose and the product labelled B in to ecosystems.
9700_w23_qp_43
THEORY
2023
Paper 4, Variant 3
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[T shows the main stages of the Calvin cycle. State precisely where the Calvin cycle occurs in plant cells. Describe how carbon dioxide is fixed in the Calvin cycle. Explain how the products of photophosphorylation are used in the Calvin cycle. Explain what initially happens to the concentration of RuBP and GP if the supply of carbon dioxide is reduced. RuBP GP RuBP triose phosphate sucrose, starch, lipids, amino acids regeneration of RuBP GP (PGA) reduction carboxylation Use
9700_s05_qp_4
THEORY
2005
Paper 4, Variant 0
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shows a scanning electron micrograph of a section through a leaf of the Christmas rose, Helleborus niger. M { } N Name M and N. M N Gases leave and enter the leaf through pores called stomata. Describe and explain how a stoma is opened. outlines the main reactions in the light-dependent stage of photosynthesis. increasing energy level light reduced NADP photosystem II light photosystem I H2O R S 2e– 2e– 2e– Name the process shown by the dotted arrows ( ). Describe what happens to water at R. State the product formed as electrons flow along S. Explain briefly the role of reduced NADP in the light-independent stage.
9700_s09_qp_4
THEORY
2009
Paper 4, Variant 0
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Questions Discovered
183