week 10 revision questions Flashcards

1
Q

Mandatory fortification

A

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

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2
Q

Voluntary fortification

A

adding nutrients to enhance product

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3
Q

Coenzyme

A

when a prosthetic group on an enzyme is an organic compound

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4
Q

Cofactor

A

when a prosthetic group on an enzyme is a metal ion

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5
Q

water-soluble vitamin that has significant storage

A

folate

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6
Q

water soluble vitamin that can be made in body

A

niacin can be endogenously synthesised by tryptophan

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7
Q

Water soluble vitamin can be damaged/reduced in concentration

A

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

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8
Q

Thiamin coenzyme

A

thiamin pyrophosphate (TPP)

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9
Q

Thiamin main function

A

a coenzyme in carb metabolism and energy release

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10
Q

Thiamin deficiency

A

berberi - anorexia, weight loss, weakness

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11
Q

Riboflavin coenzyme

A
flavin adenine dinucleotide (FAD)
flavin mononucleotide (FMN)
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12
Q

Riboflavin main function

A

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

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13
Q

Riboflavin deficiency

A

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

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14
Q

Niacin coenzyme

A

Nicotinamide adenin dinucleotide (NAD)

nicotinamide adenine dinucleotide phosphate (NADP)

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15
Q

Niacin main function

A

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

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16
Q

Niacin deficiency

A

pellagra - diarrhea, dermatitis, dementia and death

17
Q

Pantothenic acid coenzyme

A

coenxyme A (CoA)

18
Q

Pantothenic acid main function

A

coenzyme in energy metabolism and fatty acid synthesis

19
Q

pantothenic acid deficiency

A

very rare

- weakness, fatigue, impaired muscle function, GIT disturbance

20
Q

Biotin coenzyme

A

N-carboxyylbiotinyl lysine

21
Q

Biotin main function

A

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

22
Q

Biotin deficiency

A

is rare

- dermatitis, conjunctivitis, hair loss and nervous system abnromalities

23
Q

Pyridoxine coenzyme

A

pyridoxal phosphate (PLP)

24
Q

Pyridoxine main function

A

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

25
Q

Pyridoxine deficiency

A

Microcytic hypochronic anemia

26
Q

Folate coenzyme

A

tetrahydrofolic acid

27
Q

Folate main function

A

coenzyme in DNA synthesis, homocysteine metabolism

28
Q

folate deficiency

A

megaloblastic anemia, birth defects

29
Q

Cobalamin coenzyme

A

methylcobalamin

30
Q

Cobalamin main function

A

coenzyme affecting folate matabolism, homocysteine metabolism

31
Q

Cobalamin deficiency

A

pernicious anemia

32
Q

RDI for folate is expressed as ___

why?

A

folate equivalent

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

33
Q

What is meant by the methyl folate trap?

A

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

34
Q

absorption pathway of cobalamin?

A
  • 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
35
Q

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

A

Folate and cobalamin

36
Q

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

A

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.

37
Q

What is a good vegetarian food source of cobalamin?

A

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

38
Q

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

A

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 .

39
Q

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

A

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)