The light reactions of photosynthesis use _____ and produce _____.
A: NADPH … NADP+
B: water … NADPH
C: carbon dioxide … oxygen
D: carbon dioxide … sugar
E: NADPH … oxygen
The correct answer is option B.
The light-dependent reaction of photosynthesis uses water and produce NADPH.
The light-dependent reaction of photosynthesis:
The light-dependent reaction takes place at the thylakoid membrane. It uses light energy to make two molecules needed for the next stage of photosynthesis.
In the light-dependent reactions, chlorophyll absorbs sunlight energy and then converts it into chemical energy by using water molecule. The lower energy form, NADP+, picks up a high energy electron and a proton and is converted to NADPH.
12 H2O + 12 NADP+ + 18 ADP + 18 Pi + light → 6 O2 + 12 NADPH + 18 ATP.
In plants, the light-dependent reactions take place in the chloroplasts. It occurs in seven stages which are following.
- Energy is abtained from the sun.
- Break down of water moelecule occure.
- Hydrogen ions are transferred through the thylakoid membrane.
- For the 2nd Time, energy is absorbed from the sun.
- NADPH is produced from NADP+.
- Hydrogen ions diffuse through the protein channel.
- ADP is converted into ATP.
The high-energy electron travels down the electron transport chain. The electron is passed to NADP+ at the end of the chain to make NADPH.
The overall result is to convert sunlight energy into chemical energy in ATP and NADPH forms. The ATP and NADPH from the light-dependent reactions are used in the next stage of photosynthesis to make sugars.