Define photosynthesis, explain its importance, differentiate it from respiration, and describe how to test for protein using Biuret reagent.

4. a) i. What is photosynthesis?
Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy into chemical energy, producing glucose (sugar) and oxygen from carbon dioxide and water.

4. a) ii. State the importance of photosynthesis to living organisms.
Photosynthesis is crucial because it produces the organic food (glucose) that forms the base of almost all food chains, directly or indirectly sustaining all living organisms. It also releases oxygen into the atmosphere, which is essential for aerobic respiration in most life forms.

4. b) How is photosynthesis different from respiration?
Photosynthesis and respiration are opposite processes. Photosynthesis builds complex organic molecules (glucose) from simpler ones (carbon dioxide and water) using light energy, storing energy. Respiration breaks down complex organic molecules (glucose) into simpler ones (carbon dioxide and water), releasing stored energy for cellular activities. Photosynthesis occurs in chloroplasts, while respiration occurs in the cytoplasm and mitochondria.

4. c) Using the Biuret reagent only, describe experimentally how you would test for the presence of protein in a food sample.