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Flashcards in Vitamins Deck (70):
1

Water soluble vitamins (2)

Vitamin C
B vitamins

2

Fat soluble vitamins (4)

Vitamin D
Vitamin A
Vitamin K
Vitamin E

3

Vitamin definition (3)

Organic compounds required for maintenance of health
They cannot be synthesised in the body (must be provided in the diet)
They are required in very small amounts

4

Water soluble vitamin characteristics (6)

Absorbed in blood
Freely transported
Excreted readily in urine
Possible toxicity from supplements
Required in frequent doses
Mainly co enzymes for energy metabolism

5

Lipid soluble vitamin characteristics (6)

Absorbed in lymph before entering blood
Often protein bound
Stored in cells associated with fat
Less readily excreted
Toxicity is likely from supplements
Requires periodic doses

6

Name b vitamins 1-6

Thiamin
Riboflavin
Niacin
Adenine
Pantothenic acid
B6- pyridoxine, pyridoxal, pyridoxamine

7

Name b vitamins 7 to 12

Biotin
Adenosine mono phosphate
Folate
PABA
PHGA
Cobalamin

8

Which b vitamin is non-essential and which AA is it derived from?

Niacin

Tryptophan

9

Similar features of the b vitamins (4)

Co factors in different enzyme systems
Found in the same foods
Water soluble so not stored in body for long
Frequently lost

10

What are b vitamins co enzymes involved in?(4)

Release of energy from foods
Metabolism regulation
Cell division of red blood cells
Cell division of GI tract

11

What are co enzymes (3)

Organic molecules required by certain enzymes to carry out catalysis
Bind to active site of enzyme
Often function as intermediate carriers of electrons or functional groups

12

Sources of thiamin (3)

Animal products
Wheat in bread (although must be fortied as it is lost in milling)
Germinating seeds

13

What is TTP involved in?(2)

Pyruvate dehydrogenase entering TCA cycle
a-ketogluterate dehydrogenase (TCA cycle)

14

Effects of thiamin deficiency

Beri beri

15

Beri beri symptoms (4)

Fatigue
Loss appetite
Nervous system dysfunction
Heart failure

16

Sources of riboflavin (b2)

Animal products

17

What are riboflavin co enzymes (FMN/FAD) involved in?(2)

Oxidation reduction reactions including :

Electron transport
Fatty acid synthesis and oxidation

18

Name of riboflavin deficiency

Ariboflavinosis

19

Symptoms of ariboflavinosis (4)

Cracks around mouth
Blood shot eyes
Skin rash
Magnets tongue

20

Best source of niacin (B3)

Meats (also found in some cereals)

21

What is the issue with niacin from cereals (2)

Low bioavailability
Due to it being bound to compounds in cereal

22

How much tryptophan is needed to make a gram of niacin

60g

23

Functions of niacin (3)

Co enzymes forms of niacin (NAD/NADP) involved in hydrogen transfer in body
Also needed by more than 200 enzymes

Involved in carbs, lipid and protein metabolism

24

What type of reactions is NADH involved in?

What type is NADPH involved in?

Energy production reactions

Anabolic reactions

25

What is a consequence of tryptophan and niacin deficiency

Pellagra

26

85% of pantothenic acid in food is as _______

CoA

27

Key functions of CoA (3)

First step of TCA cycle
Beta oxidation of FAs
Fatty acid synthesis

28

PA deficiency symptoms (4)

Skin sensations - burning feet
Fatigue
Muscle weakness
Depression

29

What is folic acid?(3)

Synthetic form of folate
Used in dietary supplements
Absorbed better than folate

30

Which type of foods are higher in folate

Raw

31

2 forms of folate

Monoglutamte
Polyglutamate

32

Which is the main form of folate in food?

Polyglutamate

33

Roles of folate (4)

Amino acid metabolism
DNA synthesis
Cell division
Red blood cell formation

34

Effects of folate deficiency (3)

Decreased metabolism of methionine which increase homocysteine
This is a risk factor for heart disease

35

3 stages of folate deficiency

Low folate plasma due to low intake
Red blood cell folate diminishes (after 4 months)
Megaloblastic anaemia occurs

36

Megaloblastic anaemia (5)

Release of large immature erythrocytes into blood
Large cells due to decreased DNA synthesis
Failure of cells to divide properly
Leads to excess Haemoglobin
However they are ineffective at delivering oxygen

37

Benefits of folate supplementation during pregnancy

Decrease incidence of neural tube defect

38

What is neural tube defect?

Opening in spinal cord or brain

39

Sources of vitamin B12

Animal foods only

40

What prevent vegans from becoming severely B12 deficient?

Bacterial contamination in food and water we consuming produces B12

41

What can also cause B12 deficiency?

Lack of intrinsic factor in gastric juice

42

What happens to B12 after use(3)

Returns to liver
Secreted in bile
Can be used again

43

Roles of B12 (2)

Co enzyme involved in:

Folate methionine cycle
Synthesis of succinyl CoA

44

Main cause of B12 deficiency

Inadequate absorption (not intake)

45

B12 deficiency outcomes (3)

Megaloblastic anaemia
Demethylation of nerves
May induce folate deficiency (increasing homocysteine)

46

Name the B6 vitamers

Pyridoxine - alcohol form
Pyridoxamine - amine form
Pyridoxal - aldehyde form

47

Name the metabolically active form of vitamin B6

Pyridoxal phosphate (PLP)

48

Functions of B6 (2)

Co enzyme for glycogen phosphorylase
AA transamination reaction

49

Secondary causes of B6 deficiency (4)

Malabsorption
Coeliac disease
Dialysis for renal failure
Chronic alcoholism

50

Which b vitamin has higher storage than usual and why?

B12
Can be bound to a protein

51

Which lipid soluble vitamin can be a co enzyme

Vitamin K

52

What can affect b vitamins?(3)

Heat during cooking
Exposure to light
Exposure to air

53

Ultimate role of co enzymes

Helps transfer functional groups from one compound to another

54

Symptoms of pellagra - the 4 Ds

Dermatitis
Dementia
Diarrhoea
Death

55

Vitamin B6 deficiency symptoms (4)

Inflammation of tongue
Lesions around lips and mouth
Peripheral neuropathy
Anaemia

56

What is vitamin D3 known as?

Cholecalciferol

57

What is vitamin D2 known as?

Ergocalciforel

58

What is involved in vitamin A transport?(3)

Transthyretin
Lipoproteins
Retinol binding protein

59

What enzyme in vitamin C synthesis is not produced by humans

L-gulono-gamma-lactose oxidase

60

What proportion of vitamin E is excreted?

70%

61

What kind of side chain does vitamin E contain?

Isoprenoid

62

Retinol is _____ to retinyl palmitate

Esterified

63

Retinoic acid is _______ to retinal

Reduced

64

Retinol is _____ to retinal

Oxidised

65

Which organ responses to a drop in phosphorus

Kidney

66

What percentage of vitamin A is absorbed?

80

67

What is 1, 25(OH)2 also know as?

Calcitrol

68

What vitamin converts homocysteine to methionine?

B12

69

What vitamin converts homocysteine to cystathionine and then to cysteine

B6

70

Which vitamin is key for the synthesis of purines and pyrimidines?

Folate