Antioxidants and fat soluble vitamins

Question 1

fat soluble vitamins require what compounds for absorption?

Answer 1

bile salts

Question 2

tocotrienols have a role in metabolism of what compound?

Answer 2

cholesterol

Question 3

how does vitamin E react with glutathione reductase?

Answer 3

1. reacting and terminating the carbon centered radicals of free radicals
2. vitamin E has a relationship with selenium containing amino acids, which are required for glutathione and glutathione peroxidase synthesis

Question 4

what is the function of vitamin E?

Answer 4

maintenance of membrane integrity in cells by preventing oxidation of unsaturated fatty acids

Question 5

what are the functions of vitamin D?

Answer 5

1. maintain blood calcium via kidney, bone, intestine
2. cell differentiation
3. immunity

Question 6

where is 7-dehydrocholesterol synthesized?

Answer 6

sebaceous glands of skin

Question 7

UVB converts 7-dehydrocholesterol into what compound?

Answer 7

pre-vitamin D3

Question 8

the liver converts vitamin D3 into what compound?

Answer 8

25-hydroxy vitamin D3 (calcidiol)

Question 9

where does 25-hydroxy vitamin D3 (calcidiol) go after it leaves the liver?

Answer 9

kidney

Question 10

where is 25-hydroxy vitamin D3 (calcidiol) converted to 1, 25-dihydroxyvitamin D3 (calcitriol)

Answer 10

kidney

Question 11

what is the active form of vitamin D in the body?

Answer 11

1,25-dihydroxyvitamin D3 (calcitriol)

Question 12

what is the sole factor that stimulates intestinal calcium absorption?

Answer 12

vitamin D

Question 13

definition: retinal

Answer 13

prosthetic group of rhodopsin, the light harvesting pigment protein of rod cells (night blindness)

Question 14

definition: retinoic acid

Answer 14

transcriptional regulator that binds to many nuclear hormone receptors

Question 15

how does retinoic acid influence cell growth and differentiation?

Answer 15

binding to and activating specific nuclear receptor proteins that in turn bind to specific regions of DNA to stimulate or inhibit transcription

Question 16

what are the functions of vitamin K?

Answer 16

1. post-translational modification of proteins - carboxylation of glutamic acid residues (eg prothrombin to thrombin)
2. blood clotting proteins require vitamin K - prothrombin (factor II), factors 7, 9, 10
3. skeletal tissue proteins - bone G1a protei (osteocalcin) and matrix G1a protein
4. kidney G1a protein

Question 17

how does warfarin interact influence vitamin K metabolism?

Answer 17

interferes with various enzymes in the vitamin K cycle

1. quinone reductase - required to oxidize vitamin K
2. epoxide reductase - prevention of vitamin K regeneration