1. Which of the following statements about free radicals is true?
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Free radicals are considered good because they are good
oxidizing agents.
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Free radicals are considered good because they are easily
oxidized.
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Free radicals are considered bad because they are easily
oxidized by healthy tissue.
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Free radicals are considered bad because they can oxidize
healthy tissue.
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Vitamin C
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Vitamin E
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O2
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All of these are common non-enzymatic antioxidants in the human
body.
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Answer
General guidance
Antioxidants: Molecules that are capable of inhibiting oxidation in other molecules are termed as antioxidants. There are both natural and synthetic antioxidants.
Vitamin C: The chemical name of vitamin C is L-ascorbic acid. The levorotatory isomer of ascorbic acid occurs naturally and exhibits the biological activity of vitamin C. Synthetic vitamin C is purified to separate the levorotatory isomers.
Vitamin E: A class of compounds including tocopherols and tocotrienols are termed as Vitamin E.
, which is the most commonly found vitamin E.
Step-by-step
Step 1 of 6
(1) The following statements about free radicals are false. Free radicals are considered good because they are good oxidizing agents. Free radicals are considered good because they are easily oxidized. Free radicals are considered bad because they are easily oxidized by healthy tissues.
Free radicals are oxidizing agents, but they do this in an uncontrolled, non-selective fashion. This makes the manner of their reactions and the corresponding products unpredictable. Hence, they are not considered good because of their oxidizing property. Oxidation of a specie involves removal of electrons from it. Removing an electron from a free radical is not very easy because of the electron deficiency already manifest in the radical. Hence, they are not oxidized easily. Free radicals are species that are electron deficient. Oxidizing them involves the removal of electrons, which is not very easy and hence requires vigorous conditions. These conditions are barely available in most of the advanced organisms. Hence, oxidation of free radicals by healthy tissues is almost impossible.
Step 2 of 6
The right statement about free radicals would be, Free radicals are considered bad because they can oxidize healthy tissues.
Free radicals are considered bad because they can oxidize healthy tissues.
Free radicals negate their electron deficiency by abstracting a single electron from other species. This converts the species from which the electron is taken, into a free radical. This free radical further generates free radicals. These radicals react with each other and form ‘alien’ species that are useless or even harmful to the body. In effect, free radicals cause a disease in the human body because they disrupt the normal functioning of cells.
Step 3 of 6
(2) Antioxidant activity is observed from a wide range of molecules from diverse classes of biomolecules.
Antioxidants are found in various classes of biomolecules such as enzymes, carotenoids, phenolics, vitamins, mineral, saponines, and steroids.
Step 4 of 6
They are mostly covalently bonded species with varied degrees of polarity. Their molecules are relatively large in size. Hence, the given statement is false.
The given statement is ‘False’
Antioxidants are found in various classes of biomolecules such as enzymes, carotenoids, phenolics, vitamins, mineral, saponines, and steroids. These are large, mostly non-polar molecules, which are bonded covalently.
Step 5 of 6
(3) The following are common non-enzymatic antioxidants. Vitamin C Vitamin E
Antioxidants are classified as enzymatic or non-enzymatic based on their activity. Non-enzymatic antioxidants function by interrupting free radical chain reactions. Vitamin C and E are known to interrupt radical chain reactions. They are generated within the body by processing food supplements. Hence, they are quite common in the body.
Step 6 of 6
The following are not common non-enzymatic antioxidants.
Oxygen is the species responsible for oxidation of cells in an organism. Hence, it cannot be classified as an antioxidant.
Answer
Free radicals are considered bad because they can oxidize healthy tissues.
The given statement is ‘False’
Answer only
Free radicals are considered bad because they can oxidize healthy tissues.
The given statement is ‘False’