Light Dependent Stage

• What are the two purposes of the light-dependent reaction of photosynthesis?

  To produce ATP and NADPH
• What is the difference between oxidation and reduction?

  Oxidation is loss; reduction is gain
• What are the two useful products of the light-dependent reaction that enter the Calvin Cycle?

  ATP and NADPH
• Why is oxygen produced during the light-dependent reaction?

  It is a by-product of photolysis
• Where do ATP and NADPH go after they are produced?

  Into the Calvin Cycle
• What is the role of NADP⁺ in the light-dependent reaction?

  It acts as an electron and proton carrier
• What does the acronym OILRIG stand for?

  Oxidation Is Loss, Reduction Is Gain
• Why do oxidation and reduction always occur together?

  One substance loses electrons while another gains
• What is reduction in terms of hydrogen?

  Gain of hydrogen
• Is energy released or absorbed during oxidation?

  Energy is released during oxidation
• Is energy released or absorbed during reduction?

  Energy is absorbed during reduction
• What happens when chlorophyll absorbs light energy?

  It excites a pair of electrons
• Where do the excited electrons go after leaving chlorophyll?

  To an electron carrier
• How are lost electrons replaced in the photosystem?

  Through photolysis of water
• What is photolysis?

  The splitting of water molecules using light
• What are the products of photolysis of water?

  Electrons, protons, and oxygen
• What happens to protons (H⁺) during the light-dependent reaction?

  They accumulate in the thylakoid space
• What does H⁺ passing through ATP synthase produce?

  ATP
• What is the desired second product of the light-dependent reaction?

  NADPH
• What is the role of NADP in the light-dependent reaction?

  NADP is reduced to NADPH
• How is ATP made during the light-dependent reaction?

  By ADP combining with inorganic phosphate
• What is the role of chlorophyll in the light-dependent stage?

  To absorb light energy and excite electrons
• What is the term for the splitting of water using light energy?

  Photolysis
• Which enzyme helps form ATP during photophosphorylation?

  ATP synthase
• Where in the chloroplast does the light-dependent reaction take place?

  Thylakoid membranes
• What happens to the electrons lost from chlorophyll?

  They are passed along the electron transport chain
• Which molecule acts as the final electron acceptor in the light-dependent reaction?

  NADP⁺
• What is the role of electron carriers in the thylakoid membrane?

  To transport electrons and pump protons
• What is the main role of chloroplasts in photosynthesis?

  To convert light energy into chemical energy
• How are chloroplasts adapted to carry out the light-dependent reaction?

  They have a large surface area for chlorophyll
• What is the significance of the concentration gradient in ATP synthesis?

  It drives protons through ATP synthase
• What happens as H⁺ pass through the ATP synthase channels?

  They cause a structural change to produce ATP
• What is the role of light in the light-dependent reactions?

  It excites electrons in chlorophyll
• What is the basic word equation for photosynthesis?

  Carbon dioxide + water → glucose + oxygen
• What is the basic symbol equation for photosynthesis?

  $6CO_2 +$$6H_2O \rightarrow C_6H_{12}O_6 +$$6O_2$
• What is the significance of the products of the light-dependent reaction?

  They are used in the light-independent reaction
• What is the role of photophosphorylation?

  To add inorganic phosphate to ADP
• What is the role of chlorophyll in the light-dependent stage?

  To absorb light energy and excite electrons
• What is the role of NADP in the light-dependent reaction?

  NADP is reduced to NADPH
• What happens to the electrons lost from chlorophyll?

  They are passed along the electron transport chain