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a) The diagram shows a chloroplast - HSC - SSCE Biology - Question 34 - 2003 - Paper 1
Question 34
a) The diagram shows a chloroplast. (i) Name structure A. (ii) Outline the functions of structure B. (b) Identify the reactants required for the production of ATP... show full transcript
Worked Solution & Example Answer:a) The diagram shows a chloroplast - HSC - SSCE Biology - Question 34 - 2003 - Paper 1
Step 1
Step 2
Outline the functions of structure B.
Answer
Structure B refers to the stroma. Its functions include:
- Synthesis of Sugars: The stroma is the site of the Calvin Cycle, where carbon dioxide is converted into glucose using energy from ATP and NADPH.
- Enzymatic Reactions: The stroma houses enzymes necessary for the Calvin Cycle and other metabolic processes.
Step 3
Identify the reactants required for the production of ATP.
Answer
The reactants required for the production of ATP include:
- Photons (light energy): Light energy is absorbed by chlorophyll.
- Water (H2O): Water is split during the light-dependent reactions to release oxygen and provide electrons.
Step 4
Explain the role of NADPH in the Calvin Cycle.
Answer
NADPH plays a crucial role in the Calvin Cycle as a reducing agent. It donates high-energy electrons, which are necessary for the conversion of 3-phosphoglycerate (3-PGA) into glyceraldehyde-3-phosphate (G3P). This conversion helps in synthesizing glucose and other carbohydrates.
Step 5
Explain how van Helmont would have interpreted these results.
Answer
Van Helmont would have concluded that the mass of the plants increased due to the presence of water rather than soil. He would interpret the slight decrease in soil mass as indicative of plant uptake, suggesting that the plant converts water into biomass, highlighting the role of water in plant growth.
Step 6
Explain how the use of radioactive oxygen (18O) has advanced the understanding of photosynthesis.
Answer
The use of radioactive oxygen isotopes, such as 18O, has allowed scientists to trace the pathways of oxygen produced during photosynthesis. It helped reveal that oxygen released during photosynthesis comes from the splitting of water molecules and not from carbon dioxide, enhancing the understanding of the light-dependent reactions.
Step 7
Describe how you processed and analysed the gathered information.
Answer
To process and analyze the gathered information on photosynthesis products, I:
- Reviewed Literature: Examined scientific articles and studies on photosynthesis to gather data regarding its products.
- Data Compilation: Collected various statistics and experimental findings on glucose and oxygen production.
- Synthesis: Compiled the information in thematic sections to draw conclusions about the significance of photosynthesis products.
Step 8
State how you would have assessed the reliability of the data obtained.
Answer
I would assess the reliability of the data obtained by:
- Cross-Checking Sources: Comparing findings from multiple peer-reviewed studies to ensure consistency in results.
- Evaluating Methodologies: Considering the experimental methods used in the studies to ensure they are sound and reproducible.
- Sampling Size Consideration: Taking into account the sample size and control measures that support the validity of the reported outcomes.
Step 9
Evaluate the potential uses of the products of photosynthesis in replacing at least TWO named materials frequently obtained from non-renewable resources.
Answer
The products of photosynthesis, particularly glucose and oxygen, have various potential uses:
- Biofuels: Glucose can be fermented to produce ethanol, a renewable energy source that can replace fossil fuels in transportation.
- Bioplastics: The sugars derived from photosynthesis can be used to create biodegradable plastics, providing a sustainable alternative to petroleum-based plastics.