Exam - Reactive Oxygen Species and Vitamin E

Question 1

how are reactive oxygen species produced

Answer 1

as a by-product of the ETC when proper electron flow fails (leakage)

Question 2

where do reactive oxygen species occur

Answer 2

oxygen rich environments where oxygen can react with electrons

Question 3

what do radicals have

Answer 3

unpaired electrons

Question 4

what can radicals caused

Answer 4

mutations in SOD which cause ALS

Question 5

what does H2O2 get converted to H2O by

Answer 5

glutathione peroxidase and catalase

Question 6

supplement label on vitamin E

Answer 6

mixed tocopherol antioxidant support

Question 7

what is vitamin E a general term for

Answer 7

8 structurally-related compounds (vitamers)

Question 8

what are the 8 vitamers grouped into

Answer 8

4 tocopherols
4 tocotrienols

Question 9

difference between tocopherols and tocotrienols

Answer 9

tocopherols - saturated side chains with 16 carbons
tocotrienols - unsaturated side chains with 16 carbons

Question 10

which vitamer is the only one with significant activity in the body

Answer 10

alpha-tocopherol

Question 11

where are the vitamers found

Answer 11

naturally in food

Question 12

what is the antioxidant site on alpha-tocopherol

Answer 12

the hydroxyl group

Question 13

what does the alpha isoform contain more of

Answer 13

most methylated ring

Question 14

what configuration is natural alpha-tocopherol

Answer 14

RRR - fits into binding pocket of the tocopherol transport protein

Question 15

do tocopherols or tocotrienols have lower levels in food

Answer 15

tocotrienols

Question 16

where do tocotrienols have antioxidant activity

Answer 16

liver only - that’s where they stay

Question 17

food sources of vitamin E

Answer 17

nuts, seeds, vegetable oils, avocado - sensitive to preparation

Question 18

where is vitamin E stored in animals

Answer 18

adipose

Question 19

what is vitamin E RDA based on

Answer 19

only alpha-tocopherol

Question 20

while vitamin E deficiencies are rare, where can they occur

Answer 20

pre-mature infants
people with fat malabsorption disorders/gallbladders removed
people with genetic defect in lipoproteins or TTP

Question 21

what are vitamins E deficient pre-mature infants at risk for

Answer 21

hemolytic anemia because they are kept in oxygen rich incubators

Question 22

what fraction of vitamin E radical is excreted as quinone through urine

Answer 22

1/3

Question 23

what fraction of vitamin E radical is excreted as vitamin E dimer through bile

Answer 23

2/3