Big Picture
Chloroplast Structure
Light Reaction
Calvin Cycle
ATP
100


What are the two reactants of photosynthesis?


Answer: Carbon dioxide (CO₂) and water (H₂O).

100

 Where in the chloroplast do the light-dependent reactions occur?


  • Answer: In the thylakoid membranes.
100

  • What is the primary role of sunlight in the light-dependent reactions?


  • To energize electrons in chlorophyll molecules.
100

What is carbon fixation in the context of photosynthesis?

  • Answer: The process of incorporating CO₂ into organic molecules in the Calvin cycle.
100


What is the main role of ATP in cellular processes?


Answer: ATP provides energy for various cellular processes by breaking down into ADP and releasing a phosphate group.

200


What are the two main products of photosynthesis?


Answer: Glucose  and oxygen 

200


What is the function of the stroma in photosynthesis?


  • Answer: It is the site of the Calvin cycle, where CO₂ is fixed into sugars.
200

What molecule provides electrons to replace those lost by P680 in Photosystem II?


  • Answer: Water (H₂O).
200

  • What is the full name of RUBISCO

  • Answer:

Ribulose bisphosphate carboxylase oxygenase

200

If plants make ATP in the light reaction, why do they need to make it in cellular respiration?

Answer: ATP from the light reaction is used to create glucose. It does not leave the chloroplasts. Plants need ATP for the energy to do all other cellular reactions. This is made in cellular respiration.


300


What is the general chemical equation for photosynthesis?


  • 6CO2+6H2O+light→C6H12O6+6O2
300

What is the purpose of the thylakoid space in the chloroplast?


  • Answer: It accumulates protons to create a gradient for ATP synthesis.
300


  • $300 – What is the purpose of the electron transport chain in the thylakoid membrane?


  • Answer: To create a proton gradient between the stroma and the thylakoid space (lumen)  by pumping H+ ions. This powers ATP synthesis.
300


What is the role of oxidation and reduction in the calvin cycle?


Answer: NADPH from the light reaction is oxidized, reducing molecules in the 2nd phase (reduction phase) of the Calvin Cycle

300

  •  What are two differences between ATP and ADP?


  • ATP has three phosphate groups, while ADP has two. ATP has more stored energy than ADP.
400


Why is photosynthesis overall an endothermic or exothermic reaction?


endothermic

400

Where is the pH the lowest in the chloroplast?



  • the thylakoid space or lumen
400


  • What happens to the electrons at the end of the light reaction

  • They reduce NADP+ to NADPH by receiving electrons
400

In the Calvin cycle, which molecule is regenerated to ensure the continuation of the cycle, and how many ATP molecules are required for this process?

RuBP or Ribulose Bisphosphate

400

  •  In photosynthesis, how is ATP produced during the light-dependent reactions?

  • Answer: ATP is produced through photophosphorylation as protons flow down the thylakoid membrane via the electron transport chain.
500


  1.  What are two ways photosynthesis supports other organisms besides producing glucose?

  • Answer: Photosynthesis produces oxygen, which is necessary for aerobic respiration, and it creates the basis for all organic compounds--not just glucose.
500

What are two structural difference between photosystem I and photosystem II

Photosystem I Reaction center chlorophyll absorbs light at 700 nm (P700) and it is in the ETC after photosystem II

Photosystem I Reaction center chlorophyll absorbs light at 680 nm (P680) and it is in the ETC before photosystem I

500

    • How do the functions of Photosystem I and Photosystem II differ in the light reactions?

  • Answer: Photosystem II generates electrons and a proton gradient for ATP synthesis, while Photosystem I re-energizes electrons for NADPH production.
500

During the Calvin cycle, how many molecules of G3P are produced for every six molecules of CO₂ fixed, and how many of these G3P molecules are used to regenerate RuBP?

Answer: 5 molecules of G3P are used to regenerate RuBP, while one is used to form glucose

500

What are the components of an ATP or ADP molecule?

Answer: Adenine, Ribose and Phosphates

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