Write a balanced chemical symbol equation for photosynthesis, the process by which plants produce glucose.

The structure of a leaf is highly adapted to facilitate photosynthesis and gas exchange. Explain how the following parts of a leaf are adapted for these functions: (i) palisade mesophyll (ii) spongy mesophyll (iii) guard cells

A student investigates whether carbon dioxide is required for photosynthesis. The student destarches two potted plants. One plant is placed under a sealed bell jar containing a beaker of sodium hydroxide solution (which absorbs carbon dioxide). The other plant is placed under a sealed bell jar containing a beaker of water (control). Both setups are placed in bright light for 24 hours. The student then tests a leaf from each plant for the presence of starch using the following method:

• Step 1: Place the leaf in a beaker of boiling water for 30 seconds.
• Step 2: Place the leaf in a boiling tube of ethanol, put the tube in a hot water bath, and leave it for 5 minutes.
• Step 3: Rinse the leaf in cold water.
• Step 4: Spread the leaf out on a white tile and add several drops of iodine solution.

(i) Explain why the leaf is placed in boiling water in Step 1. (ii) Explain why the leaf is heated in ethanol in Step 2, and describe how the student can carry out this step safely. (iii) State the final colour observed after adding iodine solution in Step 4 for:

• the leaf from the plant in the bell jar with sodium hydroxide
• the leaf from the plant in the control bell jar (iv) Explain why it is important to destarch the plants before commencing the investigation.

Plants also require mineral ions absorbed from the soil to maintain health and produce other molecules.

Complete the table by giving the missing information: