Biochemistry- Vitamins

Front 1

Water-soluble vitamins are often used to form what?

Back 1

coenzymes

Front 2

What are the fat-soluble vitamins?

Back 2

- Vitamin A (retinol, beta carotene)
- Vitamin D (cholecalciferol)
- Vitamin K (phylloquinones, menaquinones)
- Vitamin E (tocopherols)

Front 3

Which fat-soluble vitamin is also a coenzyme?

Back 3

Vitamin K

Front 4

What is the non-B-complex water-soluble vitamins?

Back 4

Ascorbic acid (Vitamin C)

Front 5

What are the B-complex, energy-releasing, water-soluble vitamins?

Back 5

- Thiamine (Vitamin B1)
- Riboflavin (Vitamin B2)
- Niacin (Vitamin B3)
- Biotin
- Pantothenic acid

Front 6

What are the hematopoietic water-soluble vitamins?

Back 6

- Folic acid
- Vitamin B12

Front 7

What are the other B-complex, water-soluble vitamins that are not considered energy releasing or hematopoietic?

Back 7

- Pyridoxine (Vitamin B6)
- Pyridoxal
- Pyridoxamine

Front 8

What do the fat-soluble vitamins need for emulsification and uptake into mucosal cells?

Back 8

bile salts

Front 9

How are fat-soluble vitamins transported?

Back 9

They are transported via chylomicrons to the liver

Front 10

Patients with defects of lipid digestion often become deficient in what?

Back 10

lipid-soluble vitamins

Front 11

What are Vitamins A and D used for?

Back 11

They are used to form hormone-like compounds that act on the nucleus (retinoic acid and dihydroxy-vitamin D, respectively)

Front 12

What does retinoic acid (Vitamin A) do?

Back 12

Retinoic acid leads to gene expression of a variety of proteins and is essential for cellular differentiation. Another function is in the vision cycle where it acts as retinal.

Front 13

What does dihydroxy-D (Vitamin D)?

Back 13

Dihydroxy-D regulates the blood plasma levels of calcium. It also leads to the synthesis of a specific calcium-binding protein in intestinal mucosal cells.

Front 14

What is Vitamin K used for?

Back 14

Vitamin K is used in the liver to form the coenzyme for glutamyl-gabba carboxylase (GGC) which acts on specific inactive blood clotting factors and makes them more efficient for blood clotting.

Front 15

What is Vitamin E used for?

Back 15

Vitamin E acts together with Vitamin C (water-soluble non-B-complex) as radical scavenger.

Front 16

Vitamin B1 leads to what?

Back 16

thiamine pyrophosphate (TPP)

Front 17

What is thiamine pyrophosphate (Vitamin B1) a coenzyme for?

Back 17

- pyruvate dehydrogenase complex linking glycolysis to the TCA cycle
- alpha ketoglutarate dehydrogenase complex as part of the TCA cycle
- transketolase used in the reversible steps of the Pentose Phosphate Pathway (PPP)
- the enzyme complex for the degredaiton of branched-chain alpha keto acids formed after transamination of branched-chain amino acids

Front 18

What are the consequences of moderate Vitamin B1 deficiency?

Back 18

Affects mainly transketolase of the PPP. This can lead to Wernicke-Korsakoff Syndrome

Front 19

What is the treatment for Wernicke-Korsakoff Syndrome?

Back 19

treatable by vitamin infusion and later on oral vitamins

Front 20

What are the symptoms of Wernicke-Korsakoff Syndrome?

Back 20

apathy, unsteady gait while walking, mental confusion, nystagmus

Front 21

What are the consequences of severe Vitamin B1 deficiency?

Back 21

Affects the energy metabolism (PDH and TCA) and can lead to Beriberi

Front 22

Wet Beriberi

Back 22

Cardiac system. The heart cannot efficiently use lactate (PDH, TCA) or fatty acids and ketone bodies (TCA) for energy metabolism

Front 23

Dry Beriberi

Back 23

Nervous system. The brain cannot use glucose (PDH, TCA) in general or cannot use ketone bodies (TCA) during fasting

Front 24

What is Riboflavin (Vitamin B2) used to form?

Back 24

FMN and FAD. FAD contains FMN and AMP

Front 25

What is FMN a component of?

Back 25

Complex I of the ETC

Front 26

What is FAD a prosthetic group of?

Back 26

- succinate dehydrogenase (TCA)
- acyl-Coa dehydrogenase (beta oxidation
- digydrolipoyl dehydrogenase, activity of the PDH or the alpha ketoglutarate DH complex

Front 27

What does nitric oxide synthase contain?

Back 27

FMN and FAD

Front 28

Niacin (Vitamin B3) and nicotinamide (and very little trp) can be used to form what?

Back 28

NAD+ and NADPH

Front 29

What is added during the formation of NADH (NADPH)?

Back 29

hydride ion

Front 30

What occurs after the addition of a hydride ion?

Back 30

A new absorption maximum at 340 nm (photometer)

Front 31

The reduction of NAD+ leads to what?

Back 31

NADH and H+

Front 32

What is biotin a prosthetic group for?

Back 32

most carboxylations using carbon dioxide
- pyruvate carboxylase
- acetyl-CoA carboxylase
- propionyl-CoA carboxylase

Front 33

What is pantothenic acid a component of?

Back 33

CoA and also the acyl-carrier protein (ACP) of the de-novo fatty acid synthase complex

Front 34

What is Vitamin C used for?

Back 34

Vitamin C is a strong natural reducing agent

Front 35

Deficiency of Vitamin C can lead to what disease?

Back 35

Scurvy

Front 36

What is Vitamin C a coenzyme for?

Back 36

- prolyl- and lysyl-hydroxylase during procollagen synthesis
- dopamine hydroxylase (with copper) forming norepinephrine
- radical scavenger together with Vitamin E

Front 37

What is the result of Pyridoxine deficiency?

Back 37

- microcytic anemia
- amino acid metabolism
- glycogen degredation

Front 38

What is the result of Cobalamin (B12) deficiency?

Back 38

- macrocytic anemia
- CNS damage

Front 39

What is the result of folate deficiency?

Back 39

- macrocytic anemia
- neural tube defects

Front 40

How can microcytic anemia occur in Vitamin B6 (Pyridoxine) deficiency?

Back 40

Due to reduced heme synthesis, as ALA synthase lacks PLP

Front 41

What are the symptoms of Vitamin B6 (Pyridoxine) deficiency?

Back 41

general tiredness, irritability and depression. In more severe forms it leads to peripheral neuropathy and convulsions.

Front 42

Administration of ___________ is necessary during tuberculosis treatment along with isoniazid.

Back 42

Pyridoxine

Front 43

The drug isoniazid used in TB treatment leads to what kind of deficiency?

Back 43

PLP deficiency

Front 44

____________ replaces PLP in enzymes which can happen in the liver after excessive alcohol consumption.

Back 44

Acetylaldehyde

Front 45

What is PLP a coenzyme for?

Back 45

- ALA synthase for heme synthesis (glycine and succinyl-CoA)
- Aminotransferases for synthesis and degredation of amino acids
- Amino acid decarboxylases for formation of biologically active amines
- Synthesis of sphingolipids (serine and palmitoyl-CoA)
- Formation of methylene-THF from THF and serine or from THF and glycine
- Degredation of homocysteine (total degredation of methionine)
- Glycogen phosphorylase (this leads to a high demand for Vitamin B6 in muscle)

Front 46

What is the difference between the structure of Vitamin B12 and heme?

Back 46

Ring system is a corrin ring (not porphyrin) and cobalt is in the center (not iron)

Front 47

Cobalamin is needed as a coenzyme for what enzymes?

Back 47

homocysteine methyltransferase and methylmalonyl-Coa mutase

Front 48

The uptake of Vitamin B12 needs what?

Back 48

intrinsic factor (IF)

Front 49

What synthesizes intrinsic factor?

Back 49

parietal stomach cells

Front 50

What is Vitamin B12 bound to in the stomach lumen?

Back 50

intrinsic factor

Front 51

The Vitamin B12-IF complex is resistant to what?

Back 51

proteases

Front 52

The dietary Vitamin B12 is mainly transported bound to what?

Back 52

transcobalamin II

Front 53

What can Vitamin B12 deficiency lead to?

Back 53

severe, irreversible neurological damage and THF deficiency

Front 54

What is the treatment for Vitamin B12 deficiency?

Back 54

Vitamin B12 (orally or intramuscular injection) combined with leucovorin administration

Front 55

What can cause microcytic anemia?

Back 55

- Deficiency in iron
- Deficiency in copper
- Deficiency in pyridoxine

Front 56

What can cause normocytic anemia?

Back 56

Protein-calorie malnutrition

Front 57

What can cause macrocytic anemia?

Back 57

- Deficiency in Vitamin B12
- Deficiency in folate

Front 58

What minerals are abundant in humans?

Back 58

sodium, potassium, phosphate, magnesium, calcium, chloride

Front 59

What minerals are trace in humans?

Back 59

cobalt, copper, iodine, iron, molybdenum, selenium, zinc

Front 60

What is copper a cofactor for?

Back 60

- dopamine beta-hydroxylase
- cytochrom C oxidase
- superoxide dismutase
- lysyl oxidase
- tyrosinase

Front 61

Copper is toxic in what disease?

Back 61

Wilson's disease

Front 62

What is Wilson's disease?

Back 62

- Onset mostly mid-adolescence
- Defectve biliary excretion of copper
- Toxic levels of copper mainly in liver, brain and eye (lesions Kaiser-Fleischer Rings)
- Neuropsychiatric manifestation

Front 63

What is zinc a cofactor for?

Back 63

- ALA dehydrase
- carbonic anhydrase
- matrix metalloproteases (MMP) cleave collagen

Front 64

What are characteristics of zinc deficiency in children? adults?

Back 64

Children - poor growth, impaired sexual development

Adults - poor wound healing, decreased taste acuity

Front 65

Iron uptake is diminished by what?

Back 65

tannates (tea) and chlorophyll (vegetables)

Front 66

Iron uptake can be enhanced by what?

Back 66

Vitamin C

Front 67

Why is the demand for iron high in pregnant women?

Back 67

Because human milk is low in iron and newborns have a reservoir of iron lasting for about 3 months

Front 68

What is Hereditary Hemochromatosis?

Back 68

Defect in iron transport. Iron accumulation lifelong, primary defect in intestinal absorption. Symptoms show up mainly after 30-40 years with a tried of damaged organs: liver, pancreas, skin

Front 69

What are the symptoms of Hereditary Hemochromatosis?

Back 69

cirrhosis, skin pigmentation (slate-grey) and diabetes mellitus due to pancreatic damage

Front 70

In the blood, retinyl esters are transported by what?

Back 70

retinol-binding protein (RBP)

Front 71

Inside the cells, retinol is changed to what?

Back 71

Retinoic acid which has steroid hormone-like character. It will be transported into the nucleus and will lead to gene expression of specific proteins and general cellular differentiation

Front 72

Retinol can enter the retina and is is converted to what?

Back 72

cis-retinal which is involved with the vision cycle

Front 73

What is bound to opsin in the retina?

Back 73

cis-retinal which later forms rhodopsin which can be cleaved by light to all trans retinal and opsin

Front 74

All-trans retinal is changed back to what in the vision cycle?

Back 74

cis-retinal

Front 75

Deficiencies of dietary retinoids can lead to what?

Back 75

Night blindness, less fertility, slowed growth and skin problems.

Front 76

As drugs, what effects does retinol have?

Back 76

Used to treat acne and psoriasis. Can be teratogenic.

Front 77

Vitamin D (cholecalciferol) can be formed in the skin by what?

Back 77

7-dehydrocholesterol

Front 78

How does Vitamin D reach the liver?

Back 78

via chylomicrons

Front 79

In the liver, what happens to Vitamin D?

Back 79

hydroxylated to 25-OH-D

Front 80

25-OH-D is released into the blood from the liver and then what happens?

Back 80

It is taken up by the kidney and is hydroxylated again to 1,25-diOH-D

Front 81

What is the regulated step in Vitamin D metabolism?

Back 81

The formation of physiologically active 1,25-diOH-D which regulates the blood plasma levels of calcium ions

Front 82

What can deficiency of 1,25-diOH-D lead to?

Back 82

Reduced dietary calcium uptake. Rickets in children and osteomalacia in adults

Front 83

What is nutritional rickets?

Back 83

incomplete mineralization or demineralization of bone

Front 84

What is renal rickets?

Back 84

chronic renal failure leads to less 1,25-diOh-D

Front 85

Drug-Nutrient interaction: alcohol

Back 85

Deficiency - thiamine, folic acid, Vitamin B6

Front 86

Drug-Nutrient interaction: anticonvulsants

Back 86

Deficiency - Vitamin D, folic acid, Vitamin K

Front 87

Drug-Nutrient interaction: cholestyramine

Back 87

Deficiency - fat soluble vitamins, iron

Front 88

Drug-Nutrient interaction: isoniazid

Back 88

Vitamin B6

Front 89

Drug-Nutrent interaction: Oral contraceptive and estrogen

Back 89

Vitamin B6, folic acid, Vitamin B12

Front 90

What is Vitamin E used for?

Back 90

Acts as a redical scavenger together with Vitamin C

Front 91

How is Vitamin E transported to the liver?

Back 91

Via chylomicron remnants

Front 92

How is Vitamin E transported in the blood?

Back 92

transported in VLDL, LDL and HDL

Front 93

What are the three forms of Vitamin K?

Back 93

K1 - formed by plants (phylloquinone) and the uptake can be regulated via the diet
K2 - formed by intestinal bacteria (menaquinone) and uptake cannot be regulated via the diet
K3 - used as a drug

Front 94

What is Vitamin K1 formed by?

Back 94

Plants (phylloquinone)

Front 95

What is Vitamin K2 formed by?

Back 95

Intestinal bacteria (menaquinone)

Front 96

Which form of Vitamin K can be regulated via the diet?

Back 96

Vitamin K1

Front 97

What is Vitamin K a coenzyme for?

Back 97

glutamlyl-gabba-carboxylation of inactive blood cloting factors at their N-terminals in the liver

Front 98

Which blood clotting factor is in the extrinsic pathway?

Back 98

Factor Vii

Front 99

Which blood clotting factor is in the intrinsic pathway?

Back 99

Factor IX

Front 100

Which blood clotting factor is the connection of the extrinsic and intrinsic pathway?

Back 100

Factor X (Stuart factor)

Front 101

Which blood clotting factor cleaves as Factor IIa fibrinogen to fibrin?

Back 101

Factor II (prothrombin)

Front 102

__________ cleaves as ___________ to fibrin

Back 102

Factor II, Factor IIa fibrinogen

Front 103

What is another name for blood clotting Factor II?

Back 103

prothrombin

Front 104

Patients who have suffered a stroke can be given what?

Back 104

warfarin or dicumarol

Front 105

What do the drugs warfarin and dicumarol do?

Back 105

prevent "maturation" of inactive blood clotting factors in the liver

Front 106

In stroke patients, the dietary exclusion of Vitamin K alone is not sufficient. Why?

Back 106

Menaquinone is formed by bacteria

Front 107

Deficiency of blood clotting due to Vitamin K deficiency in the newborn can lead to what?

Back 107

Hemorrhagic disease (HDN)

Front 108

Why can hemorrhagic disease in the newborn occur?

Back 108

The neonatal liver is not ready for adequate prothrombin synthesis and gamma-carboxylation of inactive blood clotting factors

Front 109

In normal infants, Vitamin-K dependent blood clotting factors are about _____% of adult values at birth.

Back 109

20%

Front 110

Why is menaquinone not available in infants?

Back 110

The infant gut is sterile during the first few days of life

Front 111

What treatment is recommended for HDN?

Back 111

A prophylactic single intramuscular injection of Vitamin K