·
Explain the effects of environmental factors on the rate of photosynthesis.
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_60/2448989/771799_194498.gif)
In HKDSE Biology examination, students are required to draw the graph to indicate the effect of light intensity, carbon dioxide concentration and temperature ❗️ ❕
Light intensity ☀️
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/2448989/213760_908389.png)
- The increase of light intensity leads to an increase in photosynthesis rate.
- The rate of photochemical reaction will be enhanced due to the increase of light source.
- More ATP and NADPH will be generated from the photochemical reaction for the use in Calvin cycle.
- 🔸The rate of photosynthesis becomes constant due to the limitation of other factors.
- 🔸The rate of photosynthesis will decline at a very high temperature due to the damage of chlorophyll.
Carbon dioxide concentration 💨
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/2448989/110239_782525.png)
- The increase in carbon dioxide concentration leads to an increase in photosynthesis rate.
- The rate of Calvin cycle will be enhanced due to the increase of carbon dioxide source
- More ADP and NADP+ will be generated from Calvin cycle and use in photochemical reaction.
- 🔸The rate of photosynthesis becomes constant due to the limitation of other factors.
Temperature 🌡
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/2448989/187001_598230.png)
- Photosynthesis is catalysed by the enzyme 🔹rubisco
- The rate of photosynthesis increase when temperature increase.
- The rate of photosynthesis is the maximin in optimal temperature.
- The rate of photosynthesis decline when the temperature is higher than the optimal temperature as enzyme denatured.
That's the end of this topic 👏🏻
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_60/2448989/455295_441478.gif)
References
- Smith, E. L. (1938). Limiting Factors In Photosynthesis: Light And Carbon Dioxide. The Journal of General Physiology, 22(1), 21–35. https://doi.org/10.1085/jgp.22.1.21