Free Radicals
What characteristic makes free radicals highly reactive?
They contain unpaired electrons.
What are the two major categories of free radical sources?
Endogenous (internal) and exogenous (external).
What condition occurs when free radicals overwhelm the antioxidant defense system?
Oxidative stress.
What is the main function of antioxidants?
To neutralize free radicals and reduce oxidative damage.
What are phytochemicals?
Non-nutritive plant chemicals with protective or disease-preventive properties.
Free radicals can act as both oxidants and reductants. What determines this behavior?
Whether they lose or gain an electron.
Which external habit listed in the presentation increases exposure to free radicals?
Cigarette smoking, alcohol consumption, exposure to UV radiation, pesticides, industrial solvents.
Mention two diseases associated with oxidative stress.
Diabetes, cancer, atherosclerosis, Alzheimer's disease, Parkinson's disease, hypertension, cardiovascular disease.
Name one enzymatic antioxidant found in the human body.
Superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione reductase.
Which phytochemical gives tomatoes their powerful antioxidant activity?
Lycopene.
Name two reactive oxygen species (ROS) mentioned in the presentation.
Hydroxyl radical (OH•), superoxide ion (O₂•), hydrogen peroxide (H₂O₂), singlet oxygen, ozone, peroxynitrate.
How does hyperglycemia contribute to free radical production?
It increases glucose metabolism through pathways that promote ROS formation and decrease antioxidant defenses.
According to the presentation, how can oxidative stress damage cells?
By damaging DNA, proteins, enzymes, and lipid membranes.
What is the difference between enzymatic and non-enzymatic antioxidants?
Enzymatic antioxidants are enzymes that detoxify ROS, while non-enzymatic antioxidants are molecules that directly neutralize free radicals.
Why are plant-derived non-enzymatic antioxidants considered promising for human health?
Because they are abundant in foods, easily extracted, and help supplement the body's antioxidant defenses.