Matter is conserved during the processes of photosynthesis and cellular respiration through a series of chemical reactions that transform substances rather than creating or destroying them. Let's break down both processes to understand how this conservation occurs.
Photosynthesis
Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy into chemical energy stored in glucose. The general equation for photosynthesis can be represented as:
\[ 6 \text{CO}_2 + 6 \text{H}_2\text{O} + \text{light energy} \rightarrow \text{C}6\text{H}{12}\text{O}_6 + 6 \text{O}_2 \]
- Reactants: Carbon dioxide (\(CO_2\)) and water (\(H_2O\)) are absorbed by the plant.
- Products: Glucose (\(C_6H_{12}O_6\)) and oxygen (\(O_2\)) are produced.
In this process, the atoms from the reactants (6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms) are rearranged to form the products. There is no loss of matter; all atoms are accounted for in the products. This illustrates the law of conservation of mass: the total mass of the reactants equals the total mass of the products.
Cellular Respiration
Cellular respiration is the process by which organisms convert the chemical energy stored in glucose into ATP (adenosine triphosphate), which is usable energy for cellular processes. The general equation for cellular respiration can be represented as:
\[ \text{C}6\text{H}{12}\text{O}_6 + 6 \text{O}_2 \rightarrow 6 \text{CO}_2 + 6 \text{H}_2\text{O} + \text{energy} \]
- Reactants: Glucose (\(C_6H_{12}O_6\)) and oxygen (\(O_2\)).
- Products: Carbon dioxide (\(CO_2\)), water (\(H_2O\)), and energy (in the form of ATP).
Similar to photosynthesis, during cellular respiration, the atoms in glucose and oxygen are rearranged to form carbon dioxide and water. Again, all atoms are conserved: 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms are present in both the reactants and products.
The Cycle of Matter
Both processes are interconnected in the ecosystem:
- Photosynthesis absorbs carbon dioxide and produces oxygen.
- Cellular respiration uses oxygen and produces carbon dioxide.
This cyclical relationship helps illustrate the conservation of matter on a larger scale, demonstrating how the products of one process serve as the reactants for the other, continuously recycling matter in the biosphere.
In conclusion, matter is conserved during photosynthesis and cellular respiration through the rearrangement of atoms in chemical reactions, following the law of conservation of mass. No atoms are lost or created; they simply change form and are transferred between the two processes.