Light reactions Flashcards
What are the light reactions?
First stage of photosynthesis where light is converted into Chemical energy
Where do the light reactions happen? What organelle is this in?
The thylakoid membrane in chloroplasts
What is NADPH? What does it do?
An electron carrier that carries 2 energized electrons.
What does the thylakoid structure look like?
A pancake
Where in the thylakoids do the light reactions happen?
Photosystems
What are photosystems? What do they do?
Large complexes of proteins and chlorophyll that capture energy
What connects photosystems I and II? How do they move between the protein complexes?
ETC, e- carriers
What happens in the first step of the light reactions?
The first photosystem absorbs light energy, which excites e- entering ETC. They’re replaced with e- from H2O, making O2 as a byproduct.
What happens once e- leave first photosystem?
They flow down the ETC, releasing energy that pumps H+ (protons) into the thylakoid.
What happens in the photosystem on the right?
Light energy excites e-, which are captured by the e- carrier NADPH
What powers ATP synthase? What does this lead to?
High concentration of protons in thylakoid, ATP production
What do the light reactions produce? Where is this used?
ATP, NADPH, and O2 (byproduct), power sugar production in Calvin Cycle