micronutrients (4.3.4)

Question 1

which micronutriens help in structural function

Answer 1

calcium and phosphorus in bones/ teeth
sulfer in keratin

Question 2

which micronutrient help in thyroid hormone regulation

Answer 2

iodine (and selenium)

Question 3

what happens if iodine is inadequate

Answer 3

low T3 and T4 levels leading to excess TSH production, so the thytoid gland enlarges (Goiter)

Question 4

what is excess iron called

Answer 4

haemochromatosis

Question 5

where is iron stored

Answer 5

Ferritin protein

Question 6

name 4 enzymes containing iron and their function

Answer 6

1)Cytochromes: ATP production in mitochondria
2)Cytochrome p-450: detoxification
3)Catalase and peroxidase: prevent free radicals from damaging the cell
4)NADPH dehydrogenase/ any energy metabolism enzymes

Question 7

which glycoprotein transports iron in the blood

Answer 7

Transferrin

Question 8

what are the symptoms of iron deficiency/ anemia

Answer 8

skin paleness, shortness of breath, low blood pressure, dizziness, fatigue, fainting

Question 9

how to assess iron levels

Answer 9

Haemoglobin levels
Serum ferritin
Transferrin saturation

Question 10

what are the symptoms of zinc deficiency

Answer 10

dwarfism, diarrhoea and hypergonadism

Question 11

how to assess zinc levels

Answer 11

measure circulating levels in plasma
measure RBCs metallothionein

Question 12

what is the function of metallothionein

Answer 12

Detoxifies heavy metals (Ca, Pb, Hg) and regulates essential metal ions such as Zn and Cu

Question 13

what is the function of zinc

Answer 13

involved in nucleic acid synthesis, protein digestion, and protection against free radical formation
neuromodulator

Question 14

what is the function of bound zinc

Answer 14

stabilizes RNA + DNA structures by “zinc finger motifs”

Question 15

name 3 enzymes containing selenium and their function

Answer 15

Gluthione peroxidase (GSGPx): protects cell from free radical attack/ ROS
Thoredoxin reductase (TRs): antioxidant and regulates gene expression
Deiodinases (D1, D2, D3): catalyses removal of iodine atoms from thyroid hormones

Question 16

What are the symptoms of selenium toxicity

Answer 16

Selenosis: Vomiting, diarrhoea, hair and nail loss, lesions of the skin and nervous system

Question 17

which vitamins are lipid soluble

Answer 17

Vitamin A, D, E, K

Question 18

What is the function of vitamin A

Answer 18

Visual pigments in the retina (especially in night vision)

Question 19

what is caused by vitamin A deficiency

Answer 19

night blindness

Question 20

what is the chemical name for vitamin D

Answer 20

Calciferol

Question 21

what is the function of vitamin D

Answer 21

Maintainance of calcium levels

Question 22

what is caused by vitamin D deficiency

Answer 22

Rickets (in children)
oesteoperosis (in adults)

Question 23

which vitamins are water soluble

Answer 23

Vitamin B1, B2, B3, B6, and B12

Question 24

what is the chemical name for B9

Answer 24

Folic acid

Question 25

explain what is caused by B9 deficiency

Answer 25

Megaloblastic anaemia; abnormality in RBC production -> large RBCs

Question 26

explain what is caused by B12 deficiency

Answer 26

Pernicious anaemia (autoimmune disease); body's innability to absorb B12

Question 27

What is the chemical name for vitamin c

Answer 27

Ascorbic acid

Question 28

explain the function of vitamin C

Answer 28

Vitamin C is an antioxidant. It enhances the absorption of iron by oxidising iron from Fe 3+ (ferric iron) to Fe 2+ (ferrous iron). Fe 2+ is more easily absorbed

Question 29

List the steps of vitamin D formation from UV-rays

Answer 29

Skin | | v Cholecalciferol (inactive Vitamin D3) | | Liver hydrolysis cholecalciferol by adding OH at position 25 | v 25 Hydroxycholecalciferol (1st activation) | | Kidney hydrolysis 25 Hydroxycholecalciferol by adding OH at position 1 | v 1,25 Dihydroxycholecalciferol (Calcitriole- actual active form of vitamin D) | | | v intestinal absorption of calcium via calcium binding protein, calcium stimulating ATPase, and alkaline phosphate | | | v high plasma calcium concentration