Paper 1 All Flashcards
Where does the light-dependent reaction occur?
Thylakoid membranes
What pigment absorbs light energy
Chlorophyll
What is the name/term used to describe the excitement of electrons in Ps2 ?
Photoionisation
What happens in photoionisation? In the LDR?
Chlorophyll absorbs light energy.
This excites electrons.
Electrons move to a higher energy level and leave chlorophyll down the electron transport chain.
What happens to water in photosynthesis?
Photolysis.
Light energy splits up water molecule into proton, electrons and oxygen.
Why is photolysis essential for photosynthesis?
The electrons released during photolysis replace the electrons lost in PS2.
Also O2 released.
What powers the proton pump in LDR?
The energy from the excited electrons as they move down the electron transport chain.
Energy is used to transport H+ into thylakoid.
Where does the proton pump, pump protons into? LDR
Into the thylakoid
Why are protons pumped into thylakoid? LDR
To create proton conc gradient.
Higher conc of H+ inside thylakoid than stroma.
So H+ can then diffuse down conc gradient through ATP Synthases.
Energy from this combines ADP + Pi
Products of LDR are …
Oxygen
Reduced NADP /NADPH
ATP
How is reduced NADP made in the LDR?
Light energy absorbed by PS1 excited e- to higher energy level.
2e- are transferred to NADP with a H+ proton from the stroma to produce reduced NADP
Where does CO2 come from for the LIR?
From the air. CO2 enters through stomata, and diffuses into stroma.
Where does LIR take place?
Stroma
What does CO2 react with in the LIR?
Ribulose biphosphate
Which enzyme present in LIR?
Rubisco
