how do plants recycle hydrogen during cellular respiration

Answer 1

During cellular respiration in plants, hydrogen is not directly recycled. Instead, hydrogen is used as an electron carrier in metabolic reactions within the cells.

1. Glycolysis: The process of cellular respiration begins with glycolysis, which occurs in the cytoplasm of plant cells. During glycolysis, glucose is broken down into two molecules of pyruvate. During this process, some hydrogen atoms are transferred to NAD+ (nicotinamide adenine dinucleotide), forming NADH.

2. Citric Acid Cycle (Krebs Cycle): Pyruvate molecules from glycolysis are transported into the mitochondria, where they undergo further breakdown in the citric acid cycle. In this cycle, hydrogen atoms are transferred to coenzymes such as NAD+ and FAD (flavin adenine dinucleotide), producing NADH and FADH2.

3. Electron Transport Chain (ETC): The NADH and FADH2 generated from glycolysis and the citric acid cycle donate their high-energy electrons to the electron transport chain, which is located in the inner mitochondrial membrane. As electrons pass through the ETC, they release energy, which is used to produce ATP (adenosine triphosphate).

4. Oxygen as the Final Electron Acceptor: At the end of the electron transport chain, oxygen serves as the final electron acceptor. It combines with hydrogen ions (H+) to form water (H2O), completing the process of cellular respiration.

So, although hydrogen is not recycled in the sense that it is reused within the plant, it is used as an intermediary in the transfer of electrons during cellular respiration.