How do aerobes survive and grow in oxygen?
The correct answer and explanation is:
Aerobes are organisms that require oxygen for survival and growth. They thrive in environments where oxygen is present because they rely on it for cellular respiration, which is the process of converting nutrients, mainly glucose, into energy. This energy is stored in the form of ATP (adenosine triphosphate), which is used by cells to perform various functions.
In aerobes, oxygen acts as the final electron acceptor in the electron transport chain, which is the last step of aerobic respiration. During this process, high-energy electrons are transferred through a series of protein complexes in the inner mitochondrial membrane (in eukaryotes) or the cell membrane (in prokaryotes). As electrons pass through these complexes, energy is released and used to pump protons across the membrane, creating an electrochemical gradient.
This gradient drives the synthesis of ATP through the enzyme ATP synthase. At the end of the electron transport chain, oxygen accepts the electrons and combines with protons to form water. This is why oxygen is crucial for aerobic organisms—they rely on it to efficiently produce ATP.
In addition to the electron transport chain, aerobes also utilize glycolysis and the citric acid cycle (Krebs cycle). Glycolysis occurs in the cytoplasm and breaks down glucose into pyruvate, generating a small amount of ATP. The pyruvate is then transported into the mitochondria, where it is further broken down in the citric acid cycle, releasing more energy and electrons for the electron transport chain.
Aerobes have specialized enzymes, such as catalase and superoxide dismutase, to protect their cells from reactive oxygen species (ROS) that can form during oxygen metabolism. These enzymes help neutralize harmful free radicals, ensuring the cell’s survival in an oxygen-rich environment.