Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

46 Cards in this Set

  • Front
  • Back
Oxygen is _
Radical defintion
Reactive atom or group of atoms that contains one or more unpaired electrons
ROS definition
Highly reactive radicals derived from oxygen
Oxidative stress is _
When rate of production of ROS exceeds rate of removal by cellular defense mechanisms (enzymes, antioxidants, etc)
Name ROS
Superoxide O2 -
Hydrogen Peroxide H2O2
Hydroxyl radical OH -
How many electrons can O2 accept and describe what happens with each electron
Can accept 4 electrons
1 - Superoxide O2 -
2 - Hydrogen Peroxide H2O2
3 - Hydroxyl radical OH -
4 - Water H2O
Describe how hydroxyl radicals can be generated spontaneously
Haber Weiss Reaction - Superoxide + Hydrogen peroxide --> Oxygen + Water + Hydroxyl radical
Fenton reaction - Hydrogen peroxide is converted to hydroxyl radical and hydroxyl ion
What is the most potent ROS
Hydroxyl radical
Name some of disease states associated with ROS
Alcoholic liver disease
Ischemia reperfusion
Name 6 sources of ROS
1. Ionizing radiation - splitting water in hydroxyl and hydrogen radicals
2. Various drugs and pollutants
3. Intermediates escaping from active site of enzymes (oxygenase, cytochrome P450) and respiratory chain (CoQ)
4. Oxidase reactions producing H2O2
5. Spontaneous oxidation of hemoglobin (superoxide)
6. Respiratory burst during phagocytosis
Respiratory burst results from the activity of _ and produces _
Formation of hypochlorous acid from hydrogen peroxide is catalyzed by _
Describe cellular damage caused by ROS
Peroxidation of lipids - disrupts structural organization of membranes, aldehyde products cross link proteins
Oxidation of amino acids in proteins causes fragmentation, cross linking, aggregation, increased susceptibility to proteolytic digestion
Damage to DNA - strand breaks, base alterations ( guanine to 8 - hydroxyguanine)
Name 4 cellular defenses against oxygen toxicity
Antioxidant enzymes
Free radical scavengers
Repair mechanisms
Antioxidant enzymes
Superoxide dismutase
Glutathione peroxidase (requires Se for full activity)
Glutathione reductase
Free radical scavengers
Vitamin E
Vitamin C
Beta carotene (uric acid)
Describe compartmentation
Enzymes producing H2O2 sequestered in peroxisomes (with antioxidant enzymes)
Fe tightly bound to ferritin
Superoxygen dismutase is in mitochondria
Describe repair mechanisms
DNA repair mechanisms
Removal of oxidized fatty acids from lipids
Oxidized proteins degraded and replaced
_ can terminate free radical chain reactions in membrane lipids
vitamin E
What can scavenge free radicals
Vitamin C
What inhibits lipid peroxidation
Beta carotene
Where are flavonoids present
Green tea
Red wine
How ROS involved in atherogenesis
LDL oxidation plays role in atherogenesis
How ROS involved in ischemia - reperfusion injury
Some damage resulting from ischemic conditions may be due to excessive ROS production during reperfusion with oxygen
How ROS involved in macular degeneration
Photoreceptor /retinal pigment complex is exposed to sunlight - exposed to high oxygen levels, have high membrane content of unsaturated fatty acids
Eicosanoid family
Modified C20 fatty acids
-produced by almost every cell in the body
-potent regulators of cellular function
Parent eicosanoid is _
Arachidonic acid
Name eicosanoids
Leukotrienes and Lipoxins - produced by leukocytes, contain 3 double bonds in series
Thromboxanes - lead to blood clot formation
General functions of Eicosanoids
1. Act as hormones that DO NOT enter blood stream but act locally (autocrine + paracrine)
2. Inflammatory response - pain, swelling, fever, allergic reaction
3.Increase Water and Na excretion by kidneys
4. Regulate smooth muscle contraction - affect BP, bronchoconstriction and dilation, intestinal and uterine contractions
Arachidonic acid can be found in _
Dietary plants
Synthesized from essential fatty acids
Two major essential fatty acids from plants are
Linoleic from plant oils
Phospholipase A2 releases _
Arachidonic acid from C2 position of membrane phospholipids --> eicosanoid production
Phoshpholipase C produces _
DAG and IP3
PKC activation
Name 3 pathways of eicosanoid synthesis
Cyclooxygenase - prostaglandins + thromboxanes
Lipooxygenase - leukotrienes, HETE, lipoxins
Cytochrome P 450 - epoxides (diHETE, HETE)
These are all derived from arachidonic acid
Capital letters in prostaglandins denote _
Ring substitutions at positions 9 and 11
Arabic numbers in prostaglandins denote _
Series 1, 2, or 3 --> number of double bonds present in linear portion of hydrocarbon chain
Prostaglandin series 1
Derived from fish oils
Present is small amounts in human diet
Prostaglandin series 2
Derived from plant oils
Present in greatest amount in human diet
Prostaglandin series 3
Derived from fish oils
Present in small amounts in human diet
Stimulate - vasodilation, cAMP levels
Inhibit - platelet aggregation, leukocyte aggregation, T cell proliferation
PGF 2alpha stimulates _
Smooth muscle contraction
Cyclooxygenase is inhibited by _
Aspirin + NSAID
Thromboxan structure
6 membered ring with oxygen atom, otherwise similar to prostaglandins
Thromboxanes are produced by _
Thromboxanes cause _
Platelet aggregation
Lipooxygenase pathway generates _