Photo AI
Answer parts (a), (b) and (c) of the question on pages 2–4 of the Section II Writing Booklet - HSC - SSCE Biology - Question 35 - 2013 - Paper 1
Question 35
Answer parts (a), (b) and (c) of the question on pages 2–4 of the Section II Writing Booklet. Start each part of the question on a new page. (a) Outline the roles o... show full transcript
Worked Solution & Example Answer:Answer parts (a), (b) and (c) of the question on pages 2–4 of the Section II Writing Booklet - HSC - SSCE Biology - Question 35 - 2013 - Paper 1
Step 1
Outline the roles of the coenzymes in the light reactions.
Answer
Coenzymes play a critical role in the light reactions of photosynthesis. They assist enzymes by facilitating the conversion of light energy into chemical energy. Specifically, during these reactions:
- NADP⁺ Reduction: Coenzyme NADP⁺ captures electrons and protons to form NADPH, which is essential for the subsequent light-independent reactions.
- ATP Production: Coenzyme ADP is phosphorylated to form ATP, which serves as an energy carrier for many biochemical processes in the plant.
- Overall Function: Thus, coenzymes are vital for the energy transformation processes that occur during the light reactions.
Step 2
Describe an experiment to identify the pigments in leaves.
Answer
To identify the pigments present in leaves, the following experiment can be conducted:
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Method for Pigment Extraction:
- Cut small pieces of green leaf and immerse them in an organic solvent such as methylated spirits. This helps in extracting the pigments from the leaf cells.
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Separation of Pigments:
- Once the leaf is fully bleached (decolorized), remove it from the solvent and rinse it briefly in warm water. This step helps soften the leaf.
- Prepare a chromatography system using chromatography paper and a suitable solvent. Place a drop of the pigment solution on the paper and allow it to separate the pigments based on their solubility in the solvent.
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Means of Identification:
- After running the chromatography, compare the resulting pigment bands against known standards using a spectrophotometer to analyze the spectrum of the extracted pigment.
Step 3
What would you predict would happen to photosynthesis per unit of light if continuous light rather than flashing light were used in this experiment?
Answer
If continuous light were used instead of flashing light in this experiment, it is predicted that the yield of photosynthesis per unit of light would increase. Continuous light provides a constant supply of energy which would allow for a more stable and sustained rate of photosynthesis. In contrast, the flashing light may limit the amount of time available for the process to occur, leading to reduced photosynthetic efficiency. Therefore, the yield would likely reach a higher level if the light was uninterrupted.