Core Concepts (Target: 'S' Pass)

• Define: What is photosynthesis?

• List: What are the four things a plant needs for photosynthesis?

• Identify: What is the main food product made during photosynthesis?

• Name: What gas is released as a byproduct?

• State: Where in the plant cell does photosynthesis occur?

• Recall: What is the green pigment that absorbs sunlight?

Understanding & Application (Target: 'C' Pass)

• Explain: Why is light essential for photosynthesis?

• Write: Write the full, balanced chemical equation for photosynthesis.

• Describe: Briefly outline the steps to test a leaf for the presence of starch. What is the expected colour change for a positive result?

• Explain: Why does a plant that has been kept in a dark cupboard for two days not contain any starch in its leaves?

• Relate: How does photosynthesis help to maintain the balance of oxygen and carbon dioxide in the atmosphere?

Analysis & Higher-Order Thinking (Target: 'B' / 'A' Pass)

• Analyse an Experiment: A student sets up an experiment with an aquatic plant under a funnel in water to show that a gas is released during photosynthesis. How would the student prove that the gas collected is oxygen?

• Justify: In an experiment to prove that CO₂ is necessary for photosynthesis, a chemical like potassium hydroxide (KOH) is used. What is the specific role of KOH in this experiment?

• Synthesize: A plant with variegated (green and white) leaves is left in the sun. A starch test is then performed. Predict and explain the results for both the green and white parts of the leaf.

• Apply: Explain the flow of energy from the sun to a primary consumer (herbivore) in an ecosystem, starting with the process of photosynthesis.

O/L Exam Tip: You must know the classic experiments inside-out: testing for starch, and proving the necessity of light, CO₂, and chlorophyll. Be prepared to explain the purpose of each step and the expected observations.