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a) (i) Name a scientist from the 17th or 18th century who contributed to the development of ideas on plant growth - HSC - SSCE Biology - Question 35 - 2014 - Paper 1
Question 35
a) (i) Name a scientist from the 17th or 18th century who contributed to the development of ideas on plant growth. (ii) Outline how the findings from a 17th or 18th... show full transcript
Worked Solution & Example Answer:a) (i) Name a scientist from the 17th or 18th century who contributed to the development of ideas on plant growth - HSC - SSCE Biology - Question 35 - 2014 - Paper 1
Step 1
Step 2
a) (ii) Outline how the findings from a 17th or 18th century experiment informed a conclusion about plant growth.
Answer
Jan Ingenhousz conducted experiments showing that plants produce oxygen in the presence of light and absorb carbon dioxide. He concluded that light is essential for the growth of plants, highlighting the role of photosynthesis in plant development.
Step 3
b) Construct a flow chart to summarise the procedure used to produce named photosynthetic plant cell fractions.
Answer
- Begin with leaves of green plants.
- Grind the leaves in a buffer solution to disrupt cell membranes.
- Filter the mixture to remove solid debris.
- Use centrifugation to separate the different components based on density.
- The supernatant contains chloroplasts and other solubles.
- Isolate chloroplasts for further analysis.
Step 4
c) Explain how the design of Calvin’s experiments involving paper chromatography led to his development of an understanding of the light-independent reactions of photosynthesis.
Answer
Calvin utilized paper chromatography to separate the products of carbon fixation during photosynthesis. By analyzing the different compounds formed, he could track the pathway of carbon atoms as they were incorporated into organic molecules. This experimental design elucidated the steps of the light-independent reactions and helped identify key intermediates such as glyceraldehyde 3-phosphate (G3P).