2.2.2 Light dependent stage

Question 1

What are the two stages of photosynthesis?

Answer 1

Light independent stage
Light dependent stage

Question 2

Where does light dependent stage occur?

Answer 2

Thylakoids

Question 3

Explain the steps in light dependent stage

Answer 3

1. Light is absorbed by chlorophyll
2. Chlorophyll uses the light to split water molecules into hydrogen and oxygen
3. Oxygen is released from the plant cell. The splitting of oxygen also creates electrons
4. The electrons along with hydrogen go to a series of proteins in the thylakoid called the electron transport chain
   ( ETC )
5. In the ETC it harnesses power of electrons and hydrogens to add a phosphate onto ADP creates ATP ( 2 phosphates in ADP and 3 in ATP )
6. Once ATP is done, it is put aside. The plant will need it in the second stage of photosynthesis
7. All the extra electrons and hydrogens need to be removed. The light dependent phase stops.
8. There is a molecule called NADP+ It reacts with the hydrogen and electrons to become NADPH. That is also needed for second stage

Question 4

What are the pigments that absorb light ?

Answer 4

chlorophyll

Question 5

What are water molecules split into?

Answer 5

Hydrogen and oxygen

Question 6

How does ADP become ATP?

Answer 6

if you add an extra phosphate onto it

Question 7

Inputs of light dependent stage

Answer 7

12 Water
12 NADP+
12 ADP
12 Phosphate

Question 8

Outputs of light dependent stage

Answer 8

6 Oxygen
12 NADPH
12 ATP