Lesson Worksheet: The Light-Dependent Reactions Biology

In this worksheet, we will practice describing the reactions that occur in the light-dependent stage of photosynthesis and recalling the products formed.


What is the primary role of the proton pumps in the thylakoid membrane?

  • ATo allow the diffusion of H⁺ ions from the thylakoid lumen into the stroma
  • BTo absorb wavelengths of light to provide the energy needed for the light-dependent reaction
  • CTo actively transport H ions from the stroma into the interior of the thylakoid (the lumen)
  • DTo transport electrons along the electron transport chain


Which of the following tables correctly summarizes what happens to substances involved in the light-dependent reactions?

  • A
    EffectSynthesized SynthesizedReduced
  • B
    EffectPhotolyzed SynthesizedOxidized
  • C
    EffectPhotolyzed SynthesizedReduced
  • D
    EffectOxidized SynthesizedOxidized


Which of the following are products of the light-dependent reactions in photosynthesis?

  • AATP and water
  • BNADH and FADH
  • CADP and NADP
  • DATP and NADPH


Where in the chloroplast do the light-dependent reactions take place?

  • AIn the inner membrane
  • BIn the stroma
  • CIn the cristae
  • DIn the thylakoid membrane


At the beginning of the light-dependent reactions, water is split using light energy in a reaction known as photolysis.

What is produced when water is split in photolysis?

  • AH+, oxygen, and electrons
  • BH(g)2 and O(g)2
  • CO, H2, and protons


A product of the light-dependent reactions is oxygen. What specific process produces oxygen?

  • AThe photolysis of water
  • BThe phosphorylation of ADP
  • CThe movement of electrons through the electron transport chain
  • DThe active transport of hydrogen ions


What happens to the coenzyme NADP+ in the light-dependent stage of photosynthesis?

  • AIt loses electrons and a phosphate ion to become NAD.
  • BIt gains an oxygen ion to become oxidized NADP (NADPO+)
  • CIt gains electrons and H+ ions to become reduced NADP (NADPH).
  • DIt loses electrons and a H+ ion to form NADP+.


What is the primary role of ATP synthase in the light-dependent reactions?

  • ATo actively transport H+ ions from the stroma and into the thylakoid lumen
  • BTo phosphorylate ADP to create ATP
  • CTo actively transport electrons along the electron transport chain
  • DTo absorb wavelengths of light to provide the energy needed for the light-dependent reactions


Which charged particle generates the energy required for the phosphorylation of ADP when it moves through ATP synthase?

  • AH+
  • Be
  • CP+
  • DO


The diagram provided shows a simple outline of the light-dependent reaction, with key reactants and products removed.

What reactant has been replaced with label 1?

  • AADP
  • CWater
  • DFAD

What product has been replaced with label 2?

  • AOxygen
  • CATP

This lesson includes 23 additional questions for subscribers.

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