Nutrition 1: Vitamins fat and water and C

Question 1

What is the difference between vitamins and macronutrients

Answer 1

Macronutrients are carbohydrates, fats and proteins which are catabolised to produce energy. Can be produced by body.
Whereas Micronutrients are vitamins and minerals which are necessary for metabolic processes but we cannot synthesise them/ synthesise enough. They do not produce energy.

Question 2

How much vitamins is required for humans

Answer 2

12 vitamins, ug to mg.

Question 3

What are the key features of fat soluble hormones (ADEK) :

structure, function, absorption and storage

Answer 3

1. Fat soluble are structurally similar - all isoprenoid compounds
2. Functionally diverse- can act like hormones
3. Generally not co-enzymes or activated carriers
4. Not as readily absorbed from food.
5. Can be stored in the body, therefore buildup can lead to toxicity.

Question 4

What are the key features of water soluble hormones (Gp B + Vit C) :
structure, function, absorption and storage

Answer 4

1. Water soluble are structurally diverse
2. Functionally similar
3. Enzymes or active carriers (B vit)
4. They require modification (B vit) so precursor
5. Readily excreted + lable (easily degraded) - not toxic

Question 5

What is an activated carrier (B vitamins). What is its aka

Answer 5

These are molecules that carry activated groups in metabolism eg. electrons, Pi. They are derived from vitamin precursors of the B group. AKA COENZYME

Question 6

What carrier molecule is derived from Riboflavin (B2), what group does it carry. What is the consequences of deficiency

Answer 6

FADH2 which carries electrons.

Consequences: inflammatory diseases such as cheliosis, angular stomatitis and dermatitis

Question 7

What carrier molecule is derived from Nicotinate (niacin) B3 and what group does it carry. What is the consequences of deficiency

Answer 7

NADH + NADPH which carries electrons

Consequences: Pellagra (dermatitis, depression, diarrhoea and death)

Question 8

What carrier molecule is derived from Pantothenate (B5) and what group does it carry

Answer 8

Coenzyme A which carries acyl groups

Question 9

What carrier molecule is derived from Folate (B9) and what group does it carry. What is the consequences of deficiency

Answer 9

Tetrahydrofolate which carries one-carbon components

Consequences: Anemia and neural tube defects

Question 10

What is the function and consequence of deficiency of Vitamin A

Answer 10

function in vision, growth and reproduction. Deficiency leads to night blindness, cornea damage, respiratory and GI tract damage

Question 11

What is the function and consequence of deficiency of Vitamin C

Answer 11

Function: antioxidant/ reducing agent.

Deficiency leads to Scurvy

Question 12

What is the function and consequence of deficiency of Vitamin D

Answer 12

Function: regulation of calcium and phosphate metabolism. Deficiency leads to rickets, skeletal deformities, impaired growth in children.
In adults it leads to soft bending bones called Oestomalacia

Question 13

What are the 3 forms of Vitamin C

Answer 13

1. Intake as Ascorbic acid in diet
2. Ionised as Ascorbate (one H lost)
3. Oxidised as Dehydroascorbic acid- another H lost

Question 14

Why can humans, higher order primates not produce Vit C

Answer 14

Humans have a pseudogene for enzyme Gulonolactone oxidase which converts the last step for L-gulono y lactone into ascorbic acid.

Question 15

What are the advantages for humans not to produce Vit C

Answer 15

1. Producing Vit C involves producing H2O2 which is highly reactive oxygen species causing damage
2. Vit C regulates hypoxia inducible factor a which is a key transcriptional factor turning on stress response.
3. Pseudogenes can have signifivatn affects on regulating other genes.

Question 16

How was Vit C involved with connective tissue formation

Answer 16

Vit C is an electron donor and interacts with (monoo/di oxygenase activity) enzymes by accelerating the hydroxylation in biosynthetic pathways.

In Collagen Vit C is required for the synthesis of hydroxyproline, an amino acid which stabilises the triple helix structure of collagen by making hydrogen bonds.

Question 17

How does Vit C help proline hydroxylase do its job + what job, what required

Answer 17

Proline hydroxylase job is to add an OH to the C4 of proline and to add another O to the a-Kglutarate-> succinate.
In order to keep the reaction going it needs Fe2+ and O2 but after it does the reaction, it makes Fe3+ and CO2.

Vitamin C donates an e- to Fe3+ to make it Fe2+ so reaction can continue and in the process is oxidised to dehyrdoxyascorbate

Question 18

What is the common triplet of amino acids in collagen strands

Answer 18

Gly- Pro- Hydroxyproline, with every 3rd amino acid being Gly

Question 19

What was the two historical experiments relating to Vit C

Answer 19

Scurvy : James Lind, sailors and diet

Wound healing: John cranden cutting himself