The Light Dependent reaction

The first stage of photosynthesis

Light dependent reaction

location of the LDR

thylakoid membrane

photoionisation of chlorophyll

light energy oxidises chlorophyll excited electrons leave the chlorophyll with raised energy levels into ETC

ETC

Electron transport chain

Change in chlorophyll when it interacts with light

oxidised

Use for energy released from Electron transport chain

making ATP and reduced NAPD in chemiosmosis

Photolysis

light energy absorbed by chlorophyll splits water into ½ oxygen, H+ and e- in order to gain an electron

equation for photolysis

H20 → ½ O2 + 2e- + 2H+

what H+ ions are used for after photolysis

Bonding with NADP to form NADPH used in LIR

use for electrons after photolysis

pass along electron carrier proteins releasing energy

What oxygen is used for after photolysis

used for respiration or diffuses out of the leaf through the stomata

Chemiosmosis

energy released from electron carrier chains is used to pump protons (actively) across chloroplast membranes

where protons diffuse through the membrane to the chloroplast stroma

ATP synthase

electrochemical gradient

gradient of ions

Production of ATP

when H+ ions/protons diffuse through ATP synthase it provides energy to catalyse ADP + Pi to form ATP

Production of reduced NADP

protons and (electrons) moving back down the chemical gradient into the stroma picked up by NADP

chemiosmosis function in photosynthesis

creating a electrochemical gradient allowing protons to move down that gradient via an ATP synthase enzyme which enables the production ATP

temperature in the LDR

doesn’t affect the rate of reaction

Products of the LDR

ATP, reduced NADP, O2

order of processes in photosynthesis

Photoionisation

Photolysis

NADP is reduced

Chemiosmosis