The energy used in the CaMn cycle for the production of carbohydrate molecules comes from A. ATP B. NADPH C. H2O D. A & B E. A, B, and C During photosynthesis, photons raise electrons to higher energy levels. These excited electrons are obtained from what compound? CO2 Glucose ATP Chlorophyll H2O CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they They use Photosystems at night They fix CO2 Into sugars in bundle-sheath cells They use phosphofructokinase, which outcompetes for rubisco for CO2\" They fix CO2 Into organic adds at night They fix Co2 into pyruvate Solution Question 4 Correct option- A) ATP Explanation: If we study the role of the compounds then the answer will be cleared. ATP- It acts as energy source by losing one energy rich phosphate. ATP provides energy for the regeneration of RuBP. NADPH- Though it is a high energy rich compound but during Calvin cycle it acts as a reducing agent. NADPH provides a hydrogen ion for the reduction of 3-phospho-glycerate into glyceraldehyde-3-phosphate. H2O- Calvin Cycle Synthesizes Hexoses from Carbon Dioxide and Water. Question 5 Correct option- H2O Explanation- If we study the electron transport chain of photosynthesis then the route of electron will be cleared. The main process that generates electron is known as water splitting. Oxygen evolving complex is a protein which split water and it is associated with photosystem II . By splitting of water ½ O2 and 2H+ are generated. And 2electron is liberated. Electrons are then passed to reaction centre of chlorophyll..