light-dependent reaction - mini test

1. light-dependent reaction - mini test Where do the light-dependent reactions take place? 1 Where does photolysis occur? 1 Write a word equation for photolysis. 1 How is light energy transferred to the reaction centre of PSI and PSII? 2 Which pigment is found at the reaction centre? 1 What is photoactivation? 2 What happens to the electrons produced by PSI and PSII? 2 What is the destination of the electrons emitted from PSII? 1 Where does the electron come from to reduce the oxidised PSII? 1 What are the two products of the light-dependent reaction? 2 How and where are they produced? 4

2. Answers: • On the thylakoid membranes of the chloroplast • On the thylakoid membranes of the chloroplast • H2O 2e- + 1/2O2 + 2H+ • Through the antennae system of accesory pigment molecules. Passed on by resonance • Chlorophyll a • This is when a photon of light excites a photosystem resulting in the boosting of a primary pigment molecule’s electrons to a higher energy level • PSII electrons get passed down an ETC by cytochromes and are accepted by PSI. PSII electrons get passed down an ETC and are accepted by NADP+ light

3. PSI From the photolysis of water The energy rich compounds ATP and NADPH (+H+) ATP is produced by photophosphorylation in the ETC between PSII and PSI. NADPH (+H+) is produced when NADP+ acts as the final electron acceptor of the ETC from PSI, while also accepting H+ ions from the photolysis of water