Question

How do pathogens respond to reactive oxygen molecules?

A) They become resistant to oxidative stress.
B) They use oxygen to neutralize the molecules.
C) They produce antioxidants to counteract the effects.
D) They are damaged and may be killed by the molecules.

Answer 1

Pathogens are damaged and may be killed by reactive oxygen species (ROS), which are highly reactive molecules capable of causing cellular damage. Enzymes like superoxide dismutase and catalase help neutralize these molecules, but when ROS overwhelm these defenses, oxidative stress results, leading to cell damage.

Step-by-step explanation:

Pathogens respond to reactive oxygen species (ROS) such as peroxides and free radicals, which are highly reactive byproducts of cellular processes like mitochondrial ATP production and oxygen metabolism. When pathogens encounter these reactive oxygen molecules, they can be damaged and may be killed by the molecules (Answer D). ROS like the hydroxyl radical (OH), hydrogen peroxide (H2O2), and superoxide (O2−) can cause significant cellular damage by oxidizing lipids, proteins, carbohydrates, and nucleic acids, potentially leading to cell death.

Defense mechanisms exist within cells that neutralize many of these molecules. Enzymes such as superoxide dismutase, peroxidase, and catalase are crucial in the detoxification process. Additionally, antioxidants found in fruits and vegetables can halt the destructive reaction cascades initiated by free radicals. However, when ROS levels exceed the capacity of these defenses, oxidative stress occurs, leading to damage to cellular components, which can cause a range of diseases and is believed to be a major contributor to the aging process.