Micronutrients

Question 1

What is the chemical name for Vitamin B1?

Answer 1

Thiamine

Question 2

What is the role of thiamine?

Answer 2

Precursor to thiamine pyrophosphate, cofactor for pyruvate dehydrogenase (Pyruvate to acetyl CoA) and alpha-ketoglutarate dehydrogenase (alphaketoglutarate to succinyl CoA)

Question 3

What is the chemical name for vitamin B2?

Answer 3

Riboflavin

Question 4

What is the role of riboflavin?

Answer 4

Precursor of FAD (cofactor of glutathione synthase + electron carrier in krebs cycle) and FMN (cofactor of NADH dehydrogenase)

Question 5

What is the chemical name of vitamin B3?

Answer 5

Niacin

Question 6

What is the role of Niacin

Answer 6

Primary constituent of the coenzymes NAD+ and NADP+

Required for nutrient metabolism including cholesterol and fatty acid synthesis

Question 7

What is the chemical name of Vitamin B6?

Answer 7

Pyridoxine

Question 8

What is the role of pyridoxine?

Answer 8

Component of pyridoxal phosphate:
—involved in glycolysis, gluconeogenesis and lipid metabolism
—Synthesis of neurotransmitters
—Synthesis of haeme protein (specifically porphyrin synthesis)
—Immune function (specifically production of interleukin 2)

Question 9

Consequences of thiamine deficiency?

Answer 9

Wernicke Syndrome:
— ophthalmoplegia
— sixth nerve palsy
— nystagmus
— ptosis
— ataxia
— confusion
— coma —> death

Korsakoff’s psychosis
— where confusion persists after thiamine deficiency has been treated

Question 10

Consequences of riboflavin deficiency?

Answer 10

Anaemia
Thyroid disfunction
Eye disease
Stomatitis

Question 11

Consequences of niacin deficiency?

Answer 11

4 Ds:
— Diarrhoea
— Dermatitis
— Dementia
— Death

Question 12

Consequences of pyridoxine deficiency?

Answer 12

Infants —> convulsive seizures
Adults —> confusion, depression, insomnia

Anaemia

Difficulty walking, weakness

Question 13

What is the chemical name for vitamin B9?

Answer 13

Folic acid

Question 14

What is the role of folic acid

Answer 14

Precursor for tetrahydrofolate used in purine and pyrimidine synthesis, and amino acids

Question 15

Consequences of folic acid deficiency? What about during pregnancy?

Answer 15

Megaloblastic anaemia
Diarrhoea
Neurological symptoms

Pregnancy: important for proper neural tube closure of foetus, so deficiency can lead to defects like spina bifida

Question 16

What is the role of vitamin B12?

Answer 16

Coenzyme in reaction converting methylmalonyl CoA —> succinyl CoA, leading to neurotoxic build up of methylmalonic acid

Coenzyme in methionine synthesis from cysteine

Question 17

Consequences of vitamin B12 deficiency?

Answer 17

Megaloblastic anaemia

Neurological change

Depression and irritability

Question 18

Dietary intake of zinc?

Answer 18

4-14 mg/day

Question 19

Dietary intake of copper?

Answer 19

1.2mg/day

Question 20

Dietary intake of iron?

Answer 20

8.7mg/day

Young women = 14.8mg/day

Question 21

Zinc roles?

Answer 21

Nutrient metabolism

Immune system function

Reproductive system development

DNA and RNA polymerase activity

Question 22

Copper roles?

Answer 22

Important component of cytochrome C

Required for superoxide dismutase

Involved in connective tissue synthesis

Involved in regulation of gene expression

Question 23

Iron roles?

Answer 23

Haemoglobin synthesis

Cytochrome activity

Required in urea cycle activity

Required for cholesterol biosynthesis