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Pharmacy BSI > BSI Lecture 39-40 Free Radicals and Antioxidants > Flashcards

BSI Lecture 39-40 Free Radicals and Antioxidants Flashcards

1
Q

What is another name for free radicals?

A

Reactive Oxygen Species (ROS) or Reactive Nitrogen Species (RNS)

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2
Q

What is a free radical?

A

An atom or molecule with an unpaired electron.

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3
Q

T or F? Free radicals are very reactive with other molecules.

A

True

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4
Q

What is the name of O2 (superscript dot)?

A

Superoxide

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5
Q

What is the name of HO (superscript dot)?

A

Hydroxyl radical

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6
Q

What is the name of NO (superscript dot)?

A

Nitric Oxide

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7
Q

What are the ROS/RNS that are technically not free radical?

A

Hydrogen peroxide (H2O2) and Peroxynitrite (ONOO-)

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8
Q

What do ROS/RNS do?

A
  1. Act as signaling molecules

2. Damage other molecules (i.e proteins, lipids, nucleic acids)

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9
Q

How do ROS/RNS react with other molecules?

A
  1. Attach itself to another molecule
  2. Act as an oxidizing agent
  3. Act as reducing agents
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10
Q

Where in the cells are ROS/RNS produced?

A

Mitochondria

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11
Q

T or F? ROS/RNS are produced only in certain cells.

A

False, they are produced in all cells of the body during aerobic respiration

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12
Q

Single electrons “leak” from complexes ___ and ____ of the ETC and attach to O2 to form superoxide.

A

1; 3

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13
Q

What converts superoxide to H2O2?

A

Superoxide dismutase

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14
Q

Hydrogen peroxide is converted into H2O by what enzyme?

A

Catalase or Glutathione peroxidase (GPX)

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15
Q

Increase production of peroxide and/or an increased amount of reduced iron can cause peroxide to be converted into a _____

A

Hydroxyl radical

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16
Q

Nitric oxide and peroxy nitrite are produced in the ____________

A

Mitochondria

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17
Q

What enzyme produces Nitric oxide?

A

Nitric Oxide Synthase

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18
Q

In conditions where there is increased production of superoxide and/or nitric oxide, superoxide and nitric oxide can react to form _________

A

peroxynitrite

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19
Q

What is the ideal pathway for superoxide?

A

To be converted to H2O2 and then immediately to H2O

20
Q

T or F? White blood cells produce bleach?

A

True

21
Q

What type of cell produces superoxide, hydrogen peroxide, hydroxyl radical and hypochlorous acid?

A

White Blood Cells

22
Q

In WBC, what is the function of ROS?

A

To kill bacteria and viruses

23
Q

T or F? ROS can leak out of WBC and damage surrounding healthy tissue.

A

True

24
Q

What are the environmental/external sources which can contain or stimulate ROS/RNS production in cells?

A
  1. UV light
  2. Ionizing radiation
  3. Smoking
  4. Air pollution
  5. Medications (such as acetaminophen and doxorubicin)
25
Q

How do cells protect against ROS/RNS?

A
  1. Antioxidant
  2. Enzymatic antioxidants
  3. Non-enzymatic antioxidants
26
Q

_____ converts a reactive species into a less reactive species.

A

Antioxidant

27
Q

What are the 3 enzymatic antioxidants?

A
  1. Superoxide dismutase
  2. Catalase
  3. Glutathione peroxidase (GPX)
28
Q

List 7 non-enzymatic antioxidants

A
  1. Glutathione (GSH)
  2. Coenzyme Q
  3. Alpha-lipoic acid
  4. Vitamin C
  5. Vitamin E
  6. N-acetylcystein (NAC)
  7. Flavonoids
29
Q

______ is tripeptide consisting of cysteine, glutamate, and glycine, are synthesized in all cells of the body.

A

Glutathione (GSH)

30
Q

What are the 2 mechanisms of how GSH can neutralize ROS/RNS/Xenobiotics?

A
  1. Hydrogen peroxide (H2O2) via GPx and 2(GSH) reacting to form glutathione disulfide (GSSG) and 2 H2O
  2. GSH can also be conjugated to chemicals to neutralize them.
31
Q

T or F? When H2O2 is neutralized, GSH is being conjugated to it.

A

False, not conjugation, GSH is donating it’s H’s.

32
Q

What enzyme creates a conjugation between GSH and a xenobiotic or chemical to create a Glutathione-S-Conjugate?

A

Glutathione-S-transferase (GST)

33
Q

T or F? Conjugation can also occur without an enzyme catalyzing the reaction.

A

True

34
Q

What happens to the Glutathione-S-Conjugate after it is formed?

A

It is filtered out of the body

35
Q

What is used to determine the oxidative stress level in a cell?

A

The ratio between GSH and GSSH

36
Q

High levels of GSH and low Levels of GSSG indicates that the cell is in _____ level of oxidative stress.

A

Low

37
Q

What non-enzymatic antioxidants are produced by the body?

A

Glutathione, Coenzyme Q and Alpha-lipoic acid

38
Q

What are the 3 details of Alpha-lipoic acid?

A
  1. Water and lipid soluble
  2. Can protect against free radicals in all parts of cell
  3. It can also enhance function of vitamin C and E
39
Q

Which antioxidants are not synthesized by the body?

A

Vitamin C -Water Soluble
Vitamin E - Lipid Soluble (protects agains ROS/RNS damage in membranes)
N-Acetylcysteine (NAC)
Flavonoids

40
Q

What does N-acetylcysteine (NAC) do?

A

Acts as a donor of cysteine for GSH biosynthesis

Available as a drug (mucomyst) used to treat acetaminophen overdose

41
Q

The term used to describe an imbalance between ROS/RNS production and antioxidant status.

A

Oxidative stress

42
Q

T or F? Oxidative stress causes damage to macromolecules?

A

True

43
Q

DNA damage by ROS/RNS can lead to what?

A

Increase mutation and deletions in nuclear DNA and mtDNA (mitochondria DNA)

44
Q

Damaged proteins by oxidation or nitration can lead to what?

A

Altered activity and /or function of the protein

45
Q

Damage lipids by lipid peroxidation can lead to what?

A

Loss of membrane fluidity or altered cell signaling.

46
Q

What is the ultimate outcome of damage caused by ROS/RNS?

A

Dysfunctional cells or cell death

47
Q

What are a few diseases that are caused by oxidative stress or plays a role in the progression of the disease?

A
  1. Cancer
  2. Cardiovascular disease
  3. Alzheimer’s disease
  4. Parkinson’s disease
  5. Diabetes
  6. Many more

Pharmacy BSI (58 decks)

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