Micronutrients 1: Water-soluble And Fat (lipid)- Soluble vitamins

Question 1

What are macronutrients?

Answer 1

Carbohydrates, fats and proteins and, in humans, the catabolism of macronutrients to supply energy is an important aspect of nutrition

Question 2

What are micronutrients?

Answer 2

Vitamins and minerals, (vitamins) of which are compounds necessary for metabolic processes, but the body is either unable to synthesise them, or synthesise sufficient amounts for needs, so they must be obtained from dietary sources

Question 3

What is the traditional role of a daily multivitamin?

Answer 3

To prevent nutritional deficiency

Question 4

What are the general features of vitamins?

Answer 4

1. Required in small amounts
2. Are not building blocks for larger molecules
3. Do not yield energy when broken down
4. Humans need at least 12 vitamins in diet

Question 5

How can vitamins be grouped?

Answer 5

Into water soluble and fat soluble

Question 6

What are water soluble vitamins?

Answer 6

Vitamin B group, vitamin C

Question 7

What are fat soluble vitamins?

Answer 7

Vitamins A, D, E and K

Question 8

Which vitamins are highly variable in structure?

Answer 8

Water soluble

Question 9

What vitamins are structurally similar and all isoprenoid compounds?

Answer 9

Fat soluble

Question 10

Features of water soluble vitamins?

Answer 10

1. Functional uniformity
2. Carry mobile metabolic groups (activated carriers, co-enzymes)
3. All except vitamin C require modification for function (precursor molecules)
4. Readily excreted
5. Labile- degraded

Question 11

Features of lipid-soluble vitamins?

Answer 11

1. Functionally diverse
2. Not as readily absorbed/extracted from dietary foods
3. Generally not co-enzymes/activated carriers
4. Vit A, D act more like hormones (and are toxic in excess)

Question 12

What are almost all activated carriers that act as co-enzymes derived from?

Answer 12

Vitamins

Question 13

Co enzyme derived from riboflavin?

Answer 13

Flavin adenine dinucleotide (oxidation-reduction) deficiency leads to cheliosis and angular stomatitis (lesion of the mouth), dermatitis)

Question 14

Co enzyme derived from nicotinic acid?

Answer 14

Nicotinamide adenine dinucleotide (oxidation reduction)

Question 15

Coenzyme derived from folic acid?

Answer 15

Tetrahydrofolate (transfer of one carbon component- thymine synthesis)- deficiency leads to anemia, neural tube defects in development

Question 16

What’s the function and deficiency of vitamin C (absorbed acid)?

Answer 16

Antioxidant

Scurvy (swollen and bleeding gums, subdermal hemorrhaging)

Question 17

Function and deficiency of vitamin D?

Answer 17

Regulation of calcium and phosphate metabolism

Rickets (children); skeletal deformities, impaired growth
Osteomalacia (adults); soft, bending bones

Question 18

Deficiency of vitamin A?

Answer 18

Night blindness, cornea damage, damage to respiratory and gastrointestinal tract

Question 19

Deficiency of vitamin E?

Answer 19

Inhibition of sperm production

Lesion in muscles and nerves

Question 20

Deficiency of vitamin K?

Answer 20

Subdermal hemorrhaging

Question 21

Three forms of ascorbic acid? (Vitamin C)

Answer 21

Ascorbic acid
Ascorbate
Dehydroascorbic acid

Question 22

What is ascorbate?

Answer 22

The ionised form of ascorbic acid

Question 23

What is dehydroascorbic acid?

Answer 23

The oxidised form of ascorbate

Question 24

Can humans synthesis vitamin c?

Answer 24

No

Question 25

What step can humans not perform to achieve vitamin c biosynthesis?

Answer 25

The conversion of l-gulono-G-lactone into ascorbic acid

Question 26

What catalysed the L-gulono-G-lactone into ascorbic acid?

Answer 26

The enzyme gulonolactone oxidase

Question 27

Is the gene that codes for gulonolactone oxidase present in humans?

Answer 27

Yes, but it’s not active due to the accumulation of several mutations which have turned it into a non-functional pseudo gene

Question 28

What are two common nutritional deficiencies?

Answer 28

1. Famine

2. Vitamin C deficiency (scurvy- 2mill dead, 1:100,000 now- largely elderly, alcoholics and mental ill

Question 29

Who discovered a treatment for scurvy?

Answer 29

James Lind (12 people trial with 6 different supplements)

Question 30

What is vitamin C required for?

Answer 30

The formation of scar tissue

Question 31

What is the amino acid structure of collagen?

Answer 31

Proline, hydroxyproline (abundant) and every third is a glycine (frequent tripeptide)- other amino acids present

Question 32

What does extra cellular collagen contain?

Answer 32

Three helical peptide chains, each nearly 1000 residues long

Question 33

What does the stabilisation of the collagen triple helix require?

Answer 33

Hydroxproline (which needs vitamin c for synthesis)

Question 34

What is vitamin c?

Answer 34

An electron donor (reducing agent or antioxidant)

Question 35

What does ascorbate interact with?

Answer 35

Enzymes having either monooxygenase or dioxygenase activity

Question 36

What does vitamin c accelerate?

Answer 36

Hydroxylation in numerous bio synthetic pathways

Question 37

What is one example of the ways vitamin c acts as an electron donor for 8 enzymes in humans?

Answer 37

Three participate in hydroxylation required for collagen synthesis

Question 38

What requires vitamin c?

Answer 38

The hydroxylation of proline in collagen proteins to hydroxyproline