The science of oxidative stress and cellular damage
Key Concept: Watch this video to understand the fundamental concepts of Free Radical Injury before diving into the interactive lessons.
Free radicals are unstable molecules with unpaired electrons, making them highly reactive. Unlike stable molecules with paired electrons, free radicals desperately seek to pair with other electrons to become stable. This chemical instability makes them potentially harmful to the body.
Chain Reaction Example:
Free radical (A•) steals an electron from stable molecule (B), turning it into a new free radical (B•) that continues the chain reaction.
Free radicals attack cell membranes (lipid bilayers), creating a chain reaction that damages membrane structure and function.
Free radicals cause strand breaks and base modifications (like 8-hydroxyguanine), leading to mutations if not repaired.
Oxidation changes protein structure, causing unfolding, loss of function, and potential cellular dysfunction.
Oxidative Stress:
Occurs when free radical production overwhelms the body's antioxidant defenses, leading to cumulative cellular damage over time.
Inflammation Connection:
Free radicals and inflammation form a vicious cycle - inflammation produces free radicals which cause more tissue damage, leading to more inflammation.
Neutralization Mechanism:
Antioxidants donate electrons to free radicals without becoming reactive themselves, effectively stopping the chain reaction of cellular damage.
Exercise Paradox:
While intense exercise temporarily increases free radical production, regular exercise strengthens antioxidant defenses and makes cells more resistant to oxidative stress.
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