Light Reaction in Photosynthesis PDF

Learning Competency: Describe the patterns of electron flow through light reaction events. (STEM_BIO11/12-IIa-j-4) Specific Objectives: Determine the essential molecules involved in the light reactions; Describe the events and processes happening during light reactions; and Distinguish t...

Learning Competency: Describe the patterns of electron flow through light reaction events. (STEM_BIO11/12-IIa-j-4) Specific Objectives: Determine the essential molecules involved in the light reactions; Describe the events and processes happening during light reactions; and Distinguish the importance of sunlight to photosynthesis. Why is photosynthesis important? Photosynthesis is a vital process in which life here on Earth largely depends. As autotrophs, plants can make their food with raw materials from water, carbon dioxide, and sunlight. On the other hand, humans and other living organisms depend on plants to survive since they cannot make their food. What if photosynthesis will stop? Consequences of Photosynthesis Stopping: Decline in food and organic matter availability. Most organisms would disappear. Oxygen levels in Earth's atmosphere would deplete. Chemosynthetic Bacteria: These organisms may survive by utilizing chemical energy from inorganic compounds. They are not reliant on sunlight for energy. Stages of Photosynthesis 1. Light Reaction Stage: Occurs in the thylakoid membranes of chloroplasts. Converts light energy into chemical energy (ATP and NADPH). Produces oxygen as a byproduct. 2. Dark Reaction Stage (Calvin Cycle): Takes place in the stroma of chloroplasts. Uses ATP and NADPH to convert carbon dioxide into glucose. Does not require light but relies on the products of the light reaction. Light Reaction Events Light Reaction Events Cyclic Electron Flow