Which one of the following is the process involved in photosynthesis?
Free energy is converted into potential energy and stored
Understanding the Photosynthesis Process
Photosynthesis is a fundamental process performed by plants, algae, and some bacteria. It's how these organisms convert light energy into chemical energy, stored in the form of glucose (a sugar). This process is vital for life on Earth as it produces the oxygen we breathe and forms the base of most food chains.
Energy Conversion in Photosynthesis
The core of photosynthesis involves capturing light energy from the sun. Light energy is considered a form of free energy (energy available to do work). During photosynthesis, this free energy is used to power chemical reactions that synthesize glucose from carbon dioxide and water. The energy is then stored within the chemical bonds of the glucose molecule. Energy stored in chemical bonds is a form of potential energy.
Therefore, photosynthesis effectively converts free energy (light energy) into potential energy (chemical energy stored in glucose).
The overall chemical equation for photosynthesis is:
$$\text{6CO}_2 + \text{6H}_2\text{O} + \text{Light Energy} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + \text{6O}_2$$
Here, light energy is used to transform low-energy molecules ($\text{CO}_2$ and $\text{H}_2\text{O}$) into a high-energy molecule ($\text{C}_6\text{H}_{12}\text{O}_6$). The energy captured from light is stored in the bonds of the glucose molecule, ready to be released later through processes like respiration.
Analyzing the Given Options
Let's look at each option in the context of the photosynthesis process:
- Option 1: Potential energy is released to form free energy
This describes processes where stored energy (like in food) is broken down to release usable energy (like during respiration), not what happens during photosynthesis where energy is being stored. - Option 2: Free energy is converted into potential energy and stored
As explained above, photosynthesis captures light energy (free energy) and converts it into chemical energy stored in glucose (potential energy). This accurately describes the energy transformation in photosynthesis. - Option 3: Food is oxidized to release carbon dioxide and water
This process is called cellular respiration, which is essentially the reverse of photosynthesis. Organisms (including plants) break down glucose (food) in the presence of oxygen to release energy, producing carbon dioxide and water as byproducts. This is not photosynthesis. - Option 4: Oxygen is taken, and carbon dioxide and water vapour are given out
Taking in oxygen and releasing carbon dioxide is characteristic of respiration in most organisms. While plants do respire, the dominant gas exchange during active photosynthesis is the uptake of carbon dioxide and release of oxygen. Releasing water vapour is transpiration, a different process. This option does not correctly describe the gas exchange directly involved in the synthesis part of photosynthesis.
Conclusion on Photosynthesis Process and Energy
Based on the analysis, the process involved in photosynthesis that correctly describes the energy transformation is the conversion of free energy into potential energy for storage within organic molecules like glucose.
Revision Table: Photosynthesis Key Concepts
| Concept | Description |
|---|---|
| Primary Function | Convert light energy into chemical energy (glucose). |
| Energy Input | Light energy (Free Energy). |
| Energy Output/Storage | Chemical energy stored in glucose (Potential Energy). |
| Inputs (Reactants) | Carbon Dioxide ($\text{CO}_2$), Water ($\text{H}_2\text{O}$), Light Energy. |
| Outputs (Products) | Glucose ($\text{C}_6\text{H}_{12}\text{O}_6$), Oxygen ($\text{O}_2$). |
| Location | Chloroplasts (in plants and algae). |
Additional Information on Energy Forms and Photosynthesis
Understanding the types of energy involved helps clarify photosynthesis.
- Free Energy: Energy that is available to do work under isothermal and isobaric conditions. Light energy is a form of free energy that plants can capture.
- Potential Energy: Stored energy based on position or chemical structure. The energy stored in the chemical bonds of glucose molecules is potential energy. This energy is released when the bonds are broken, such as during respiration.
Photosynthesis is an anabolic process, meaning it builds complex molecules from simpler ones, requiring an input of energy. This energy comes from light and is stored, increasing the potential energy of the system (specifically, in the glucose molecule). This stored chemical energy can then be used by the plant or by organisms that consume the plant.
Important Questions from Life Processes
Which element is needed by the thyroid gland to produce thyroxine hormone?
What is the purpose of making urine in the human body?
Identify the correct match of plant hormones with their functions.
What is required for the synthesis of thyroxin hormones?
Which of the following receptors help in the detection of taste?
