Light Dependant Reactions

Question 1

Where do the light-dependent reactions take place?

Answer 1

In the thylakoid membrane

The thylakoid membrane is a system of interconnected membranes within chloroplasts.

Question 2

What happens when light hits PSII?

Answer 2

It excites electrons in chlorophyll A

PSII stands for Photosystem II, which is a complex of proteins and pigments.

Question 3

What is the pathway of electrons in the light-dependent reactions?

Answer 3

Electrons move down the electron transport chain (ETC) to PSI

PSI stands for Photosystem I, which also plays a role in the light-dependent reactions.

Question 4

What occurs during the splitting of water in the lumen?

Answer 4

Releases O₂, H⁺, and electrons

This process is known as photolysis and is essential for providing electrons to replace those lost by PSII.

Question 5

What is produced when electrons from PSI reduce NADP⁺?

Answer 5

NADPH

NADPH is an important electron carrier used in the Calvin cycle.

Question 6

What happens to H⁺ ions during the light-dependent reactions?

Answer 6

Build up → diffuse through ATP synthase → produce ATP

This process is known as chemiosmosis.

Question 7

What are the outputs of the light-dependent reactions?

Answer 7

O₂, ATP, NADPH

These outputs are essential for the subsequent light-independent reactions (Calvin cycle).