week 10 revision questions

Question 1

Mandatory fortification

Answer 1

replacing lost nutrients
It is the compulsory fortification of food to replace nutrients lost in processing and to add nutrients that are deemed important for public health. Examples: Iodine in salt, folate and thiamin in flour for making bread, vitamin D in margarine

Question 2

Voluntary fortification

Answer 2

adding nutrients to enhance product

Question 3

Coenzyme

Answer 3

when a prosthetic group on an enzyme is an organic compound

Question 4

Cofactor

Answer 4

when a prosthetic group on an enzyme is a metal ion

Question 5

water-soluble vitamin that has significant storage

Answer 5

folate

Question 6

water soluble vitamin that can be made in body

Answer 6

niacin can be endogenously synthesised by tryptophan

Question 7

Water soluble vitamin can be damaged/reduced in concentration

Answer 7

during food preparation/cooking when exposed to heat, light, oxygen and alkaline substance

Question 8

Thiamin coenzyme

Answer 8

thiamin pyrophosphate (TPP)

Question 9

Thiamin main function

Answer 9

a coenzyme in carb metabolism and energy release

Question 10

Thiamin deficiency

Answer 10

berberi - anorexia, weight loss, weakness

Question 11

Riboflavin coenzyme

Answer 11

flavin adenine dinucleotide (FAD)
flavin mononucleotide (FMN)

Question 12

Riboflavin main function

Answer 12

coenzyme in numerous oxidation-reduction reactions including those of energy release

Question 13

Riboflavin deficiency

Answer 13

ariboflavinosis - inflammation of mouth and tongue, crack in corner of mouth

Question 14

Niacin coenzyme

Answer 14

Nicotinamide adenin dinucleotide (NAD)

nicotinamide adenine dinucleotide phosphate (NADP)

Question 15

Niacin main function

Answer 15

coenzyme in numerous oxidation-reduction reactions in energy metabolism, synthesis and breakdown of FAs

Question 16

Niacin deficiency

Answer 16

pellagra - diarrhea, dermatitis, dementia and death

Question 17

Pantothenic acid coenzyme

Answer 17

coenxyme A (CoA)

Question 18

Pantothenic acid main function

Answer 18

coenzyme in energy metabolism and fatty acid synthesis

Question 19

pantothenic acid deficiency

Answer 19

very rare

- weakness, fatigue, impaired muscle function, GIT disturbance

Question 20

Biotin coenzyme

Answer 20

N-carboxyylbiotinyl lysine

Question 21

Biotin main function

Answer 21

coenzyme for carboxylase enzymes that particpate in fatty acid, amino acid and energy metabolism

Question 22

Biotin deficiency

Answer 22

is rare

- dermatitis, conjunctivitis, hair loss and nervous system abnromalities

Question 23

Pyridoxine coenzyme

Answer 23

pyridoxal phosphate (PLP)

Question 24

Pyridoxine main function

Answer 24

coenzyme in amino acid metabolism, heme synthesis, lipid, metabolism, homocysteine metabolism

Question 25

Pyridoxine deficiency

Answer 25

Microcytic hypochronic anemia

Question 26

Folate coenzyme

Answer 26

tetrahydrofolic acid

Question 27

Folate main function

Answer 27

coenzyme in DNA synthesis, homocysteine metabolism

Question 28

folate deficiency

Answer 28

megaloblastic anemia, birth defects

Question 29

Cobalamin coenzyme

Answer 29

methylcobalamin

Question 30

Cobalamin main function

Answer 30

coenzyme affecting folate matabolism, homocysteine metabolism

Question 31

Cobalamin deficiency

Answer 31

pernicious anemia

Question 32

RDI for folate is expressed as ___

why?

Answer 32

folate equivalent

to accound for both folate (green leafy veges) and folic acid (fortified foods) and their different in bioavailability

Question 33

What is meant by the methyl folate trap?

Answer 33

transfer of methyl group from 5MeTHFA to cobalamin to make them both biologically active
if one is deficient the other is stuck in non active form

Question 34

absorption pathway of cobalamin?

Answer 34

• Cobalamin is bound to protein in food, e.g. meat
• Bioavailability from food sources: 11% in liver, 24-40% in egg-fish, >60% in mutton /chicken
• Cobalamin released by action of HCl and pepsin in stomach
• Free cobalamin binds to R-protein (from salivary cells + parietal cells)
• In small intestine, pancreatic proteases release cobalamin from R- protein
• Free cobalamin binds to intrinsic factor (IF) (from parietal cells) - IF + B12 travel to and are absorbed in the terminal ileum by endocytosis

Question 35

What are two water soluble vitamins that are stored in the liver in significant amount?

Answer 35

Folate and cobalamin

Question 36

Why is the RDI for niacin stated as “niacin equivalents”?

Answer 36

This is to include the niacin found naturally in food and the niacin that can be produced (endogenously) from tryptophan from dietary protein in the diet.

Question 37

What is a good vegetarian food source of cobalamin?

Answer 37

The answer can include anything found in a “vegetarian diet” e.g. egg or dairy products; or also “B12 fortified foods” - for vegan.

Question 38

What is the typical cause leading to pernicious anemia in elderly?

Answer 38

Atrophic gastritis: resulting in poor production of IF; loss of good teeth for eating/chewing meat; decreased HCl production: unable to free B12 from protein adequately; antibody against IF: B12 can’t not bind on IF .

Question 39

How does ascorbic acid specifically contribute to the formation of strong collagen?

Answer 39

To form the triple helix of collagen, lysine and proline must be hydroxylated (to form hydroxyproline and hydroxylysine). Lysil and prolil hydroxylases are the metalloenzymes performing the hydroxylation. Iron is the cofactor to these enzymes. Ascorbic acid keeps the iron in the reduced form in order for enzymatic activity to continue (the iron is oxidized when the enzymatic activity takes place)