Antioxidant enzymatic defense system
noun phrasePronunciation: /ˌæntiˈɒksɪdənt ɛnˌzaɪˈmætɪk dɪˈfɛns ˈsɪstəm/
The coordinated network of catalytic proteins including superoxide dismutase (SOD), catalase (CAT), and peroxidases that neutralize reactive oxygen species (ROS) generated during abiotic stress. This system prevents oxidative damage to cellular lipids, proteins, and nucleic acids.
Plain English
Protective enzymes that plants use to remove harmful oxygen molecules produced during stress conditions.
Etymology & History
Usage
"The antioxidant enzymatic defense system, particularly elevated SOD and CAT activity, mitigates oxidative stress during water deficit conditions."
Style guide notes: Specify enzyme names (SOD, CAT) when discussing mechanisms; use full term when providing overview of plant defenses.
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Frequently Asked Questions
How do antioxidant enzymes prevent cellular damage?
SOD converts superoxide to hydrogen peroxide; CAT and peroxidases break H₂O₂ into harmless water and oxygen molecules.
Why is this system important during abiotic stress?
Stress conditions generate excess ROS that damage membranes and proteins; enzymatic defenses prevent this secondary damage.
Why Test Candidates on This?
Essential examination content for stress physiology covering oxidative stress mechanisms and plant defense biochemistry.
Required skill level: Mid