Photosynthesis
Photosynthesis is the process by which plants take energy from sunlight and convert it to glucose. When you actually stop and think about that, it’s insane. Imagine if we could do that, that would be awesome.
Plants are green because of the chemical chlorophyll, where the process of photosynthesis takes place.
Photosynthesis is a two-step process, so I will break the process up into its components.
Photosynthesis
Photosynthesis is a series of chemical reactions that take place in the chloroplast in plant cells. It is the process by which light energy from the sun is converted to glucose.
Plant cells require glucose for respiration (discussed in Unit 1). Glucose can also be stored in plant cells as starch, as well as used for structure as cellulose (component of plant cell walls).
Step 1 - The Light Reaction
Light energy from the sun shines on plant cells and enters the chlorophyll (the green chemical within the chloroplast).
Here, the light energy is converted to chemical energy. ATP is also created in this process.
This chemical energy is used to split water into oxygen and hydrogen.
The oxygen then diffused from the cell, and hydrogen moves onto the next stage of photosynthesis.
So, light energy from the sun converts into chemical energy, which splits water into Oxygen and hydrogen, and ATP is made in the process.
Step 2 - Carbon Fixation
Hydrogen and ATP from the light reaction is used for step 2 of photosynthesis.
Through a series of enzyme-controlled reactions, Hydrogen and Carbon Dioxide (with the help of ATP) are used to produce sugar.
The process of photosynthesis is very efficient, however, in reality there will often be a limiting factor, limiting the amount of sugar than can be generated from light. This limiting factor may be:
Carbon dioxide concentration
Temperature
Light intensity
Nutrients available
Graphically, these limiting factors can be identified.
It’s worth noting the importance of photosynthesis to life on Earth other than plants. In the process, CO2 is taken in and oxygen is expelled, which allows life to have a healthy supply of oxygen and keeps carbon dioxide levels low in our atmosphere.
Key Points!
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Photosynthesis
Photosynthesis is the process by which plants take energy from sunlight and convert it to glucose.
Photosynthesis is a series of chemical reactions that take place in the chloroplast in plant cells.
-
The Light Reaction
This chemical energy is used to split water into oxygen and hydrogen.
The oxygen then diffused from the cell, and hydrogen moves onto the next stage of photosynthesis.
So, light energy from the sun converts into chemical energy, which splits water into Oxygen and hydrogen, and ATP is made in the process.
-
Carbon Fixation
Hydrogen and ATP from the light reaction is used for step 2 of photosynthesis.
Through a series of enzyme-controlled reactions, Hydrogen and Carbon Dioxide (with the help of ATP) are used to produce sugar.
The process of photosynthesis is very efficient, however, in reality there will often be a limiting factor, limiting the amount of sugar than can be generated from light. This limiting factor may be:
* Carbon dioxide concentration
* Temperature
* Light intensity
* Nutrients available