lec 14 slide 11

what are the two parts to photosynthesis

• light reactions where electron transfer reactions occur

• dark reactions where carbon fixation occurs

what happens first and where

the first that happens is at a reaction center where photons from sunlight energize wan electron in CHLOROPHYLL that sends that electron into the ETC

what does chlorophyll do

when missing an electron, it pulls an electron from water to regenerate itself

how many times is need for water to oxidize to make oxygen

4x

With the electron that was put into the ETC, what happens

as it is transferred, the ETC pumps protons into the thylakoid space from the stroma, creating a PROTON GRADIENT

What is the proton gradient used for

to synthesize ATPs via ATP synthase

going back to that electron but in another reaction center what happens

it is going to get energized AGAIN by light where the energy is ultimately used to reduce NADP+ to NADH

what do these steps in photosynthesis make up

the light reaction and they are confined to the chloroplast

what about the dark reawctions

they DONT require sunlight and start in the chloroplast but are finished in the cytoplasm

what do the dark reactions use

2 products of the light reaction for carbon fixation of CO2 into macromolecules

what happens to the two products in the dark reaction

are ATP (energy to drive reactions) and NADPH (a source of high energy electrons)

what do most plants use in the day

BOTH light and dark reactions happen during the day since they are highly linked processes