Photosynthesis

Which of the following best indicates that the light reactions of photosynthesis have completed and that the Calvin Cycle has begun?

ATP and NADPH accumulate in the stroma -The light reactions of photosynthesis are completed once energy from light is transferred to ATP and NADPH. ATP and NADPH are then transported to the stroma to begin powering the production of carbohydrates from carbon dioxide during the Calvin cycle

When light is absorbed by pigments in photosystem II (PSII), energy is passed inward from pigment to pigment until it reaches the reaction center. Electrons are then boosted to a high energy level and captured by the primary electron acceptor. Which of the following occurs immediately after the electrons from PSII are captured by the primary electron acceptor?

water is broken down -after the electrons from PSII are exckited, an enzyme splits a water molecule into one oxygen atom, two hydrogen atoms, and two electrons. These two electrons replace the excited electrons lost from PSII

RuBisCO catalyzes the joining of carbon dioxide with RuBP during carbon fixation.In an experiment, researchers apply a toxin to a plant that inhibits RuBisCO. Which of the following explains the most likely effect this toxin will have on the Calvin Cycle?

Carbon dioxide will not be converted into carbohydrates -the toxin inhibits RuBisCO from catalyzing the joining of carbon dioxide with RuBP. This prevents carbon fixation, so the Calvin Cycle will not occur. Without the Calvin Cycle, carbon dioxide will not be converted into carbohydrates

Which of the following best explains how the light reactions of photosynthesis generate ATP?

a proton gradient drives the formation of ATP from ADP and inorganic phosphate via ATP synthase -energy from light excites electrons and initiates their transport through the electron transport chain (ETC). As electrons pass through the ETC, a proton gradient forms across the thylakoid membrane. This gradient drives the synthesis of ATP from ADP and inorganic phosphate via ATP syntha

The cytochrome b6f complex is an intehral thylakoid membrane protein that forms an electrochemical gradient by pumping protons. In an experiment, researchers apply a toxin to a plant cell that inhibits the cytochrome b6f complex which of the following explains the most likely effect of this toxin on the light reactions of photosynthesis?

ATP synthesis will mot occur -atp synthesis requires an electrochemical gradient to form across the thylakoid membrane. The toxin prevents the cytochrome b6f complex from forming a electrochemical gradient, so ATP synthesis will not occur during the light reactions of photosynthesis

Which of the following best describes how the Calvin cycle and the light reactions of photosynthesis function together?

The Calvin cycle produces ATP and NADPH generated by the light reactions to synthesize carbohydrates -the light reactions of photosynthesis produce ATP and NADPH. These molecules are then used to power carbohydrates during the Calvin cycle