Nutrients, Oxidation and Antioxidants Flashcards Preview

CMBM exam 3 > Nutrients, Oxidation and Antioxidants > Flashcards

Flashcards in Nutrients, Oxidation and Antioxidants Deck (85)
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1

Is vitamin E water or lipid soluble?

Lipid soluble

2

Is vitamin C water or lipid soluble?

Water soluble

3

What is oxidative stress?

O2 will steal an electron from a reduced metal, flavin etc and become superoxide) O2-

4

Superoxide and its products are known as;

Reactive Oxygen Species or ROS

5

The gas hormone nitric oxide (NO) is known as a;

Reactive Nitrogen Species (RNS)

6

How are ROS and RNS formed?

By accident in the electron transport chain
On purpose by immune cells

7

What can have its structure modified by oxidative or nitrosative stress?

Proteins, lipids, carbohydrates, individual nucleotide bases

8

Is it good or bad that a hydroxyl group can react with anything around it?

Bad

9

What can aldehydes do that are considered bad?

Create cross links between proteins

10

How is iron important?

Key role in many enzymes (cytochromes)
Catalysis and electron transfer, oxygen transport

11

How is iron toxic?

It is insoluble in presence of oxygen
Catalyzes the Haber-Weiss-Fenton Reactions
Produces a free radical hydroxyl

12

How does iron help defend against the toxins it makes?

With Superoxide dismutase to aid in conversion of superoxide to more stable form

13

Where and how is iron stored?

In ferritin and hemosiderin mostly in the liver

14

What molecule moves iron from various organs and cells into tissues and bones?

Transferrin

15

How much iron should a person have in a day to maintain stores?

At least 8 mg

16

How is the transferrin receptor complex internalized?

By receptor medicated endocytosis

17

How is iron release?

By acidification

18

How is non-heme iron uptake inhibited?

By phytate and polyphenols in common food (plant sources) like;
- black tea
- cocoa
- chamomile
Polyphenols numerous rings chelate the iron increasing its elimination

19

How is iron uptake stimulated?

Vitamin C
Organic acids
Heme

20

What is a hereditary excess in iron called?

Hemochromatosis

21

What is a dietary overload of iron called and how can someone get it?

Hemosiderosis
Alcohol (red wines) and over using supplements (children)

22

What drugs does iron decrease the absorption of?

Thyroxine, tetracyclin, ciprofaloxacin
occurs because numerous rings on the molecules act as chelators and this more effectively eliminates the drug and iron along with it

23

What is anemia?

Abnormally low blood hemoglobin

24

What enzymes can protect you from reactive oxygen species?

Superoxidase dismutases
Catalases
Peroxidases

25

What chemicals can protect you from ROS?

Bilirubin, glutathione, catalase, vitamin E, B-carotene and ascorbate (vit C)

26

What is glutathione?

A small tripeptide reversibly oxidized/reduced and can be regenerated by NADPH and glutathione reductase

27

Superoxide Dismutase

catalyzes superoxide to hydrogen peroxide

28

What is the danger in an ischemic/reperfusion injury?

the initial return of oxygen creates a burst of ROS species

29

Reactive Nitrogen species -RNS

NO
Peroxynitrite is ONOO- which is O2- + NO

30

Although H2O2 is not a free radical but ...

it can generate free radicals by encountering a transition metal