NHM 454 EXAM 2 QUESTIONS AND ANSWERS
What determines if a compound can act as an antioxidant? - CORRECT ANSWER✅✅if a compound can
donate a hydrogen or electron and not become a radical itself, it is a compound with antioxidant
potential. It is all about the chemical structure of the compound.
What does oxidation and reduction reactions involve? - CORRECT ANSWER✅✅involves the transfer of
oxygen, hydrogen, or electrons
What is oxidation and reduction reactions commonly referred to as? - CORRECT ANSWER✅✅redox
reactions
What is an antioxidants? - CORRECT ANSWER✅✅substances which markedly delay or prevent the
oxidation of a substrate
Resonance stability - CORRECT ANSWER✅✅stability of antioxidant after it donates either a H+ or e-
What are the antioxidant actions in a compound? - CORRECT ANSWER✅✅3 ways: 1) they can donate
hydrogen or electon to a free radical;; 2) bind metals or compounds that can initate oxidation;;
3)antioxidant can bind to free radical (servces as stabilizer)
What is oxidation by O2? reduction? - CORRECT ANSWER✅✅gain of oxygen --- loss of oxygen
What is redox reaction by H transfer? - CORRECT ANSWER✅✅oxidation = loss of a hydrogen ----
reduction = gain of a hydrogen
What is redox reaction by electron transfer? - CORRECT ANSWER✅✅oxidation = loss of electrons ---
reduction = gain of electrons
Most common type of redox reaction? - CORRECT ANSWER✅✅By transfer of H+
H+ to be extracted from protein, lipid, DNA
,Hydrogen Atom Transfer Mechanism - CORRECT ANSWER✅✅H+ have to be added to the compound
that was oxidized in order to stabilize it
What is the compound stability based on? - CORRECT ANSWER✅✅the instability of the valence shell is
in free radicals and where antioxidants come in
What can be a free radical? - CORRECT ANSWER✅✅ANY compound that has lost an e- from its valence
shell
Can an O2 become a free radical? How? - CORRECT ANSWER✅✅Yes becuase of their role in generation
of ATP -- terminal electron acceptor in mitochondria that in its ground state, oxygen has two unpaired
electrons in outer shell. electrons have the same spin, so oxygen can only receive one electron at a time
int he ETC. the rate of the elctrons in ETC stomeimes slows or speeds --> free electron linkage occurs.
when they link the readily bind oxygen, if the rate excessed the ability of oxygen to bind, free radicals
will form due to a leark OR superoxide can form from the slowing flow that causes a oxygen to spin out
with one free valence electron in cell
How much of oxygen results in production of reactive oxygen species? - CORRECT ANSWER✅✅2-5% of
oxygen in gneeration of ATP
What is a source of oxidative stress? Why? Quenches this stress? - CORRECT ANSWER✅✅exercise is a
source of oxidative stress due to increase O2 intake --- food quenches it
What is superoxide? - CORRECT ANSWER✅✅an oxygen that became a free radical due to the unpaired
valence electron in its outer cell
What is ROS? - CORRECT ANSWER✅✅reactive oxidative species
free radicals containing O2 (w/ unpaired e- in outer shell)
are strong oxidants and can be beneficial
detrimental at high levels
What are examples of ROS? - CORRECT ANSWER✅✅hydroxyl radical, singlet oxygen, hydrogen
peroxide, peroxyl radical, etc.
, What does excess ROS do? - CORRECT ANSWER✅✅overwhelms protective enzymes resulting in
oxidative stress (destroying tissues/disrupting DNA)
What is the most potent radical? - CORRECT ANSWER✅✅oxygen
What are endogenous antioxidant enzymes? - CORRECT ANSWER✅✅superoxide dismutase
gluathione peroxidase
catalase
glutathone reductase
*produced based on amnt of BASAL oxidative stress*
What were endogenous antioxidant enzymes created for? - CORRECT ANSWER✅✅By body to:
-quench the radicals created to aeorbic respiration
-detoxify/breakdown oxidative species
What causes disease onset? - CORRECT ANSWER✅✅increase oxidative stress and inadequate diet
What are endogenous source for free radicals? - CORRECT ANSWER✅✅aerobic respiration
peroxisomes
cytochrome P450
phagocytic cells
(these sources cant be avoided and diet must compensate)
What do peroxisomes do? - CORRECT ANSWER✅✅breaks down fatty acids
How do peroxisomes create free radicals? - CORRECT ANSWER✅✅produce hydrogen peroxide as by
product of breakdown of FA
(endogenous source)
What determines if a compound can act as an antioxidant? - CORRECT ANSWER✅✅if a compound can
donate a hydrogen or electron and not become a radical itself, it is a compound with antioxidant
potential. It is all about the chemical structure of the compound.
What does oxidation and reduction reactions involve? - CORRECT ANSWER✅✅involves the transfer of
oxygen, hydrogen, or electrons
What is oxidation and reduction reactions commonly referred to as? - CORRECT ANSWER✅✅redox
reactions
What is an antioxidants? - CORRECT ANSWER✅✅substances which markedly delay or prevent the
oxidation of a substrate
Resonance stability - CORRECT ANSWER✅✅stability of antioxidant after it donates either a H+ or e-
What are the antioxidant actions in a compound? - CORRECT ANSWER✅✅3 ways: 1) they can donate
hydrogen or electon to a free radical;; 2) bind metals or compounds that can initate oxidation;;
3)antioxidant can bind to free radical (servces as stabilizer)
What is oxidation by O2? reduction? - CORRECT ANSWER✅✅gain of oxygen --- loss of oxygen
What is redox reaction by H transfer? - CORRECT ANSWER✅✅oxidation = loss of a hydrogen ----
reduction = gain of a hydrogen
What is redox reaction by electron transfer? - CORRECT ANSWER✅✅oxidation = loss of electrons ---
reduction = gain of electrons
Most common type of redox reaction? - CORRECT ANSWER✅✅By transfer of H+
H+ to be extracted from protein, lipid, DNA
,Hydrogen Atom Transfer Mechanism - CORRECT ANSWER✅✅H+ have to be added to the compound
that was oxidized in order to stabilize it
What is the compound stability based on? - CORRECT ANSWER✅✅the instability of the valence shell is
in free radicals and where antioxidants come in
What can be a free radical? - CORRECT ANSWER✅✅ANY compound that has lost an e- from its valence
shell
Can an O2 become a free radical? How? - CORRECT ANSWER✅✅Yes becuase of their role in generation
of ATP -- terminal electron acceptor in mitochondria that in its ground state, oxygen has two unpaired
electrons in outer shell. electrons have the same spin, so oxygen can only receive one electron at a time
int he ETC. the rate of the elctrons in ETC stomeimes slows or speeds --> free electron linkage occurs.
when they link the readily bind oxygen, if the rate excessed the ability of oxygen to bind, free radicals
will form due to a leark OR superoxide can form from the slowing flow that causes a oxygen to spin out
with one free valence electron in cell
How much of oxygen results in production of reactive oxygen species? - CORRECT ANSWER✅✅2-5% of
oxygen in gneeration of ATP
What is a source of oxidative stress? Why? Quenches this stress? - CORRECT ANSWER✅✅exercise is a
source of oxidative stress due to increase O2 intake --- food quenches it
What is superoxide? - CORRECT ANSWER✅✅an oxygen that became a free radical due to the unpaired
valence electron in its outer cell
What is ROS? - CORRECT ANSWER✅✅reactive oxidative species
free radicals containing O2 (w/ unpaired e- in outer shell)
are strong oxidants and can be beneficial
detrimental at high levels
What are examples of ROS? - CORRECT ANSWER✅✅hydroxyl radical, singlet oxygen, hydrogen
peroxide, peroxyl radical, etc.
, What does excess ROS do? - CORRECT ANSWER✅✅overwhelms protective enzymes resulting in
oxidative stress (destroying tissues/disrupting DNA)
What is the most potent radical? - CORRECT ANSWER✅✅oxygen
What are endogenous antioxidant enzymes? - CORRECT ANSWER✅✅superoxide dismutase
gluathione peroxidase
catalase
glutathone reductase
*produced based on amnt of BASAL oxidative stress*
What were endogenous antioxidant enzymes created for? - CORRECT ANSWER✅✅By body to:
-quench the radicals created to aeorbic respiration
-detoxify/breakdown oxidative species
What causes disease onset? - CORRECT ANSWER✅✅increase oxidative stress and inadequate diet
What are endogenous source for free radicals? - CORRECT ANSWER✅✅aerobic respiration
peroxisomes
cytochrome P450
phagocytic cells
(these sources cant be avoided and diet must compensate)
What do peroxisomes do? - CORRECT ANSWER✅✅breaks down fatty acids
How do peroxisomes create free radicals? - CORRECT ANSWER✅✅produce hydrogen peroxide as by
product of breakdown of FA
(endogenous source)
