Redox Biology Flashcards

1
Q

What does Redox stand for?

A

Reduction and Oxidation

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2
Q

what is OILRIG?

A
Oxidation
Is
Loss (Of Electrons)
Reduction
Is
Gain (Of Electrons)
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3
Q

What is a ROS?

A

Reactive Oxygen Species

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4
Q

What is Superoxide?

A

Oxygen with an extra electron(O2e-). A free radical

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5
Q

What is another name for ROS?

A

RONS: Reactive Oxygen Nitrogen Species

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6
Q

What are free radicals?

A

Any species capable of independent existence that contains 1 or more unpaired electrons.

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7
Q

What is the relationship between ROS and Free Radicals

A

All Free Radicals are ROS but not all ROS are free radicals

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8
Q

What are some free radicals apart from superoxide?

A

Hydroxyl radical

Nitric Oxide

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9
Q

What is an example of a ROS that isn’t a free radical?

A

Hydrogen Peroxide, H2O2

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10
Q

What are the two types of Antioxidants?

A

Dietary and Enzymatic

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11
Q

Give some examples of dietary antioxidants

A

Vitamin C and E

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12
Q

What is a key enzymatic antioxidant?

A

SOD; Superoxide Dismutase

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13
Q

What is a key antioxidant cofactor, and what is it called when reduced or oxidised?

A

Glutathione (reduced; GSH. oxidised; GSSG)

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14
Q

What is Oxidative Stress?

A

When the ROS outweigh the antioxidants

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15
Q

What is Redox Balance?

A

The ratio of ROS to Antioxidants

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16
Q

Is ROS always bad?

A

No. Low levels of ROS cause adaptation, only when the levels get too high do they cause damage.

17
Q

What is the relationship beteen exercise intensity/volume and ROS?

A

Low intensity is associated with low ROS production, and so adaptation. High intensity associated with higher ROS production, and so damage.

18
Q

What is the relationship between activity level and ROS concentration?

A

High when sedentary/inactive, decreases until you ebecome active, but starts to increase as you become very active/elite, though not as high as sedentary.

19
Q

Other than Biomarkers, how do you indirectly measure ROS?

A

Place a probe into contracting muscle, infuse a liquid into the probe that would be oxidised by ROS. Measure how much of it is oxidised as it comes out of the muscle

20
Q

How do you use biomarkers to measure ROS?

A
  • Measure the concentration of antioxidants
  • Measure biomarkers in plasma, muscle or cells that are linked to changes in protein, lipids or DNA. (e.g. pentane in exhaled air, or MDA due to lipid peroxidation by ROS)
21
Q

When does peak damage to proteins occur after exercise?

A

4 hours post

22
Q

When does Glutathione hit lowest levels after exercise?

A

2 hours post

23
Q

How is cortisol affected by exercise?

A

The greater the intensity of exercise the greater the cortisol secretion

24
Q

What role does AMP play in redox biology?

A

It is a byproduct of recycling ATP that needs to be removed, and produces Uric acid as a result

25
Q

What is the first step of AMP being removed from the cell?

A

Turned into IMP and NH3 using water, and Adenylate Deaminase.

26
Q

What is IMP converted into?

A

Inosine, which, with inorganic phosphate, converts to hypoxanthine

27
Q

What is hypoxanthine converted to?

A

Xanthine, then Uric Acid

28
Q

What is the relevance of Uric Acid in Redox balance?

A

Uric Acid leads to an antioxidant response

29
Q

What are the two methods by which AMP is converted to ammonia and uric acid?

A

Xanthine Dehyrogenase system and Xanthine Oxidase system.

30
Q

What system of AMP breakdown is primarily used in tissue hyperoxia?

A

Xanthise dehydrogenase

31
Q

What system of AMP breakdown is primarily used in tissue hypoxia?

A

Xanthise oxidase

32
Q

Explain the Xanthine Dehydrogenase system

A

Hypoxanthine is converted to Xanthine, then Uric Acid, by oxidising NAD to NADH

33
Q

Explain the Xanthine Oxidase system

A

Hypoxanthine is converted to Xanthine then Uric acid, by oxidising oxygen to superoxide.

34
Q

What is a biomarker of DNA damage?

A

8-oxoguanine