Correct Option
The correct option is 2 only
Explanation
Respiration is a vital biochemical process in which cells break down organic substances, primarily glucose, to release energy. From a chemical perspective, it is characterized as an exothermic oxidation reaction.
Statement-wise Analysis
- Statement 1 is Incorrect: Aerobic respiration involves the complete oxidation of glucose ($C_6H_{12}O_6$) in the presence of oxygen ($O_2$). This chemical breakdown results in the release of energy, which is stored in the form of Adenosine Triphosphate (ATP) for cellular use.
- Statement 2 is Correct: Respiration is an exothermic reaction because it releases energy into the surroundings (or stores it as ATP). Endothermic reactions, such as photosynthesis, require the absorption of energy to proceed.
- Statement 3 is Incorrect: The primary byproducts of aerobic respiration are Carbon Dioxide ($CO_2$) and Water ($H_2O$). Oxygen is consumed as a reactant in this process, whereas it is released as a byproduct in photosynthesis.
Key Takeaway
Respiration is an exothermic process involving the oxidation of glucose to release energy, producing Carbon Dioxide and Water as byproducts. The general equation is: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{Energy}$.