Photosynthesis | Light dependent reaction | Light independent reaction

PHOTOSYNTHESIS 

Photosynthesis is the process by which autotrophic organism use light energy to make sugar and oxygen gas by carbon dioxide and water.

1. Light dependent reaction 
2. Light independent reaction 

LIGHT DEPENDENT REACTION 

• Takes place in thylakoids ( contain chlorophyll )
• Requires ligjt
• Convert light energy into chemical energy. 
• Light independent reaction depends on the end product ( reduced NADP and ATP)  of light dependent reaction.

NON CYCLIC PHOTOPHOSPHORYLATION

• Involves two photosystems ( P 680nm and P700nm) 
• These photosystem contain chlorophyll a and chlorophyll b as well as necessary pigment. 
• Flow of electron is NON CYCLIC. 
• Uses the photolysis of water. 
• End products are reduced NADP,  ATP and oxygen. 

CYCLIC PHOTOPHOSPHORYLATION

• Involves only photosystem 1 ( at 700 nm) 
• End products is ATP only. 

LIGHT INDEPENDENT REACTION 

• Also known as Calvin cycle. 
• Takes place in the stroma of the chloroplasts.
• No light required but need the end products (reduced NADP and ATP) of light dependent reaction reduced NADP and ATP to produce simple sugars.
• Need an enzyme RUBISCO ( Ribulose biophosphate carboxylase) and carbon dioxide. 

FACTOR AFFECTING PHOTOSYNTHESIS 

• The rate of photosynthesis is defined in term of the rate of oxygen  production per unit mass of green plant tissue or per unit weight of total chlorophyll. 

The main factors are-

1. Light intensity 
2. Wavelength 
3. Co2 concentration 
4. Temperature 
5. water supply 
6. Chlorophyll concentration 
7. Pollution