FFA Floriculture Practice Test

During respiration, plants primarily use which gas?

1. Nitrogen

2. Carbon dioxide

3. Oxygen

4. Hydrogen

The correct answer is: Oxygen

During respiration, plants primarily use oxygen. This process occurs in the mitochondria of plant cells, where oxygen is utilized to break down glucose and release energy in the form of ATP (adenosine triphosphate). The consumption of oxygen during respiration is essential for converting stored energy from carbohydrates into a usable form for the plant's metabolic activities. In contrast, while carbon dioxide is an important gas for photosynthesis (the process plants use to convert light energy into chemical energy), it is not used during respiration. Nitrogen is not involved in the respiration process as it mainly serves other roles in the plant, such as contributing to protein synthesis and growth. Hydrogen, while essential in various biochemical processes, does not play a direct role in the gas exchange during respiration. Therefore, the utilization of oxygen is crucial for the energy production phase of a plant's life cycle, marking it as the primary gas used during respiration.