Nutritional biochemsitry Flashcards

1
Q

What substance is most likely deficient following excess consumption of raw eggs?

A

biotin

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2
Q

The use of ___ and ingestion of ___ may cause a deficiency in biotin.

A

antibiotics

raw eggs

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3
Q

What are the major biochemical functions of potassium?

A

maintains fluid and electrolyte balance across membranes, maintains pH, maintains excitability of nerves

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4
Q

Name three clinical consequences of taking too much vitamin D.

A

hypercalcemia, loss of appetite, stupor

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5
Q

Symptoms: hemolysis, neurologic problems, retinitis pigmentosa. Vitamin deficiency?

A

Vitamin E

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6
Q

Where is the body is calcium distributed?

A

99% bone

1% in blood/tissues

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7
Q

Vitamin C facilitates absorption of ___.

A

iron

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8
Q

Name two symptoms caused by a deficiency of vitamin A.

A

night blindness and dry skin

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9
Q

What are the three main causes of vitamin B12 deficiency?

A

malabsorption, lack of IF, absence of terminal ileum

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10
Q

What is the precursor of coenzyme A?

A

panthothenate (B5)

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11
Q

Where in the body is phosphorus distributed?

A

85% bone

15% as esters (lipids, proteins, anhydrides) and inorganic phosphate

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12
Q

Where in the body is selenium distributed?

A

kidney, heart, liver, pancreas, muscle

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13
Q

Name three key enzymes that require ascorbate as a cofactor. Identify the related pathways.

A

prolyl and lysyl hydroxylases (collagen synthesis)

dopamine hydroxylase (catecholamine synthesis)

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14
Q

Symptoms: metaplasia of corneal epithelium, dry eyes, bronchitis, pneumonia, follicular hyperkeratosis. What vitamin deficiency?

A

vitamin A

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15
Q

Name the crucial vitamin that must be included in the treatment of an alcoholic with hypoglycemia.

A

thiamine

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16
Q

What does a deficiency of vitamin B1 cause?

A

Beriberi dz and Wernicke-Korsakoff syndrome

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17
Q

Where is vitamin K synthesized?

A

in the intestines by normal flora

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18
Q

When vitamin B6 is converted to ___, it is a cofactor in what three processes?

A

pyridoxal phosphate

cofactor in transamination, decarboxylation, trans-sulfuration

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19
Q

Name the enzyme type that requires niacin (B3) as a cofactor.

A

dehydrogenases

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20
Q

Name the vitamin that is a cofactor for oxidative decarboxylation of alpha-keto acids and is involved with the enzyme transketolase in the HMP shunt.

A

B1 (thiamine)

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21
Q

Vitamin C is necessary for the ___ of proline and lysine in ___ synthesis.

A

hydroxylation

collagen

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22
Q

Vitamin C is necessary as a cofactor for the conversion of dopamine to ___.

A

norepinephrine

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23
Q

What are the major biochemical functions of selenium?

A

a component of glutathione peroxidase, which helps to destroy free radicals, protection against heavy metal toxicity

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24
Q

Vitamin E functions as an ___ to protect RBCs from ___.

A

antioxidant

hemolysis

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25
Q

Where in the body is potassium distributed?

A

major intracellular cation

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26
Q

What are the major biochemical functions of chromium?

A

forms glucose tolerance factor (w/ nicotinic acid)

GTF promotes formation of disulfide bridges between insulin and its receptor, improving uptake of glucose into cells

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27
Q

Why does thiamine deficiency have such strong neural symptoms?

A

B1 is a cofactor of pyruvate dehydrogenase

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28
Q

Deficiency of vitamin E causes?

A

increased fragility of erythrocytes

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29
Q

Name four enzymes that require pantothenic acid as a cofactor. Identify the related pathways.

A

fatty acid synthase (fatty acid metabolism), fatty acyl CoA synthase (fatty acid metabolism), pyruvate dehydrogenase (PDH), alpha-ketoglutarate dehydrogenase (TCA)

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30
Q

Name the two key enzymes that require cyanocobalamin (B12) as a cofactor. Identify the related pathways.

A

homocysteine methyl transferase (Met, SAM), methylmalonyl-CoA mutase (odd chain FAs, valine, met, ile, thr)

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31
Q

What substance is most likely deficient? Sxs: megaloblastic macrocytic anemia, neural tube defects, homocysteinemia, DVT

A

folate

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32
Q

What are the major biochemical functions of calcium?

A

mineralization of bone, contraction of muscles, membrane permeability, propagation of nerve signals, coagulation and enzyme regulation

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33
Q

Where in the body is copper distributed?

A

muscle, bone, liver, kidney, brain

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34
Q

Name the enzyme class that requires riboflavin (B2) as a cofactor.

A

dehydrogenase

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35
Q

The absorption of fat-soluble vitamins depends largely on what two organs?

A

small intestine, pancreas

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36
Q

Name the enzymes that require thiamine as a cofactor. Identify the related pathways.

A

pyruvate dehydrogenase (PDH), alpha-ketoglutarate dehydrogenase (TCA), transketolase (HMP shunt)

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37
Q

What vitamin does NAD come from?

A

Niacin (B3)

38
Q

What are the clinical findings of scurvy?

A

swollen gums, bruising, anemia, poor wound healing

39
Q

Name the enzyme required for the final conversion of Vitamin D to 1,25-vitamin D.

A

1-alpha-hydroxylase

40
Q

What substance is most likely deficient? Symptoms: alcoholism, ataxia, nystagmus, ophthalmoplegia, high output cardiac failure, confabulation psychoses

A

thiamine (B1)

41
Q

Name three symptoms of beriberi.

A

polyneuritis, cardiac pathology, edema

42
Q

Name three enzymes that require biotin as a cofactor. Identify the related pathways.

A

pyruvate carboxylase (gluconeogenesis), acetyl-CoA carboxylase (FA synthesis), propionyl-CoA carboxylase (odd chain FA, valine, met, ile, thr)

43
Q

In which population is a thiamine deficiency most often observed?

A

alcoholics

44
Q

What is the major activated carrier of CO2 in the body?

A

biotin

45
Q

What is the storage form of Vitamin D?

A

25-OH D3

46
Q

What coagulation factors require Vitamin K?

A

factors II, VII, IX, X

proteins C, S

47
Q

Prolonged exposure to broad spectrum antibiotics causes a deficiency of which vitamin? Why?

A

vitamin K

destruction of intestinal bacteria that supply vitamin K

48
Q

What are the major biochemical functions of manganese?

A

collagen formation, cholesterol synthesis, mitochondrial superoxide dismustase, maintain normal brain chemistry.

49
Q

Name the enzymes(s) that require pyridoxine (B6) as a cofactor. Identify the related pathway(s).

A

aminotransferases (protein catabolism), AST, ALT (heme synthesis)

50
Q

Where in the body is magnesium distributed?

A

50% bone
25% muscle
25% extracellular tissues

51
Q

Folic acid is important in the synthesis of ___.

A

nitrogenous bases in DNA and RNA

52
Q

A patient has cirrhosis of the liver. Which enzyme action may be altered in the synthesis of Vitamin D?

A

25-hydroxylase

53
Q

Folic acid is important in the synthesis of ___.

A

Nitrogenous bases in DNA and RNA

54
Q

Biotin is a cofactor for which three carboxylations?

A

pyruvate to oxaloacetate, acetyl-CoA to malonyl CoA, and propionyl-CoA to methylmalonyl-CoA

55
Q

What substance is most likely deficient? Symptoms: poor wound healing, easy bruising, perifolicular hemorrhage, bleeding gums, increased bleeding time, painful glossitis, anemia

A

ascorbate

56
Q

Name the enzyme defect in rickets. Where is the defect located?

A

1-alpha hydroxylase

proximal renal tubules

57
Q

What substance is most likely deficient? Symptoms: diarrhea, dementia, dermatitis

A

niacin (B3)

58
Q

Vitamin D increases the intestinal absorption of ___ and ___.

A

calcium and phosphate

59
Q

Where in the body is sodium distributed?

A

major extracellular cation

60
Q

What substance is most likely deficient? Symptoms: megaloblastic macrocytic anemia, progressive peripheral neuropathy

A

B12

61
Q

What are the major biochemical functions of iron?

A

oxygen transport (hemoglobin), oxygen storage (myoglobin), cofactor in ETC to generate ATP, activates O2 in WBCs to kill bacteria

62
Q

What are the major biochemical functions of sodium?

A

maintains fluid and electrolyte balance across membranes, maintains pH, maintains excitability of nerves

63
Q

Name the vitamin deficiency. Sxs: increased bruising and increased prothrombin time.

A

vitamin K (not C - there is normal PT in deficiency)

64
Q

Name the vitamin that is deficient in breast milk and is often postnatally injected.

A

vitamin K

65
Q

A deficiency in vitamin B5 causes what four problems?

A

dermatitis, enteritis, alopecia, adrenal insufficiency

66
Q

Bone pain and muscle weakness is most clearly associated with a deficiency of which fat soluble vitamin?

A

vitamin D

67
Q

Where in the body is manganese distributed?

A

throughout body, but concentrated in bone, liver, pancreas, and kidney

68
Q

Vitamin B12 is involved in which two conversions?

A

homocysteine to methionine and metholmalonyl-CoA to succinyl-CoA

69
Q

What is the major biochemical function of magnesium?

A

cofactor for many ATP involving reactions

70
Q

What are the major biochemical functions of copper?

A

cytochrome oxidase in the ETC, estrogen degradation, cytosolic SOD (defense against free radicals)

71
Q

The conversion of 7-dehydrocholesterol to cholecalciferol occurs where?

A

skin

72
Q

Cholecalciferol, also called ___, is formed where?

A

D3

sun-exposed skin

73
Q

What is the MC vitamin deficiency in North America?

A

folic acid

74
Q

Maintenance of healthy epithelium and vision are major functions of which vitamin?

A

vitamin A

75
Q

What are the major biochemical functions of phosphorus?

A

mineralization of bone; DNA, RNA, and ATP synthesis; enzyme regulation (phosphorylation), acid-base balance

76
Q

What substance is most likely deficient? Sxs: sideroblastic anemia, cheilosis, stomatitis, convulsions

A

pyridoxine (B6)

77
Q

Where is vitamin B12 stored?

A

liver

78
Q

Where in the body is iron distributed?

A

hemoglobin, myoglobin, transferrin in blood, ferritin in liver, spleen, bone marrow

79
Q

Excess endogenous vitamin D is seen in what disease state?

A

sarcoidosis, where epithelial macrophages convert vitamin D into its active form

80
Q

Where in the body is chromium distributed?

A

iron in kidney, liver, muscle, spleen, heart, pancreas, bone

81
Q

Is toxicity more common for fat or water soluble vitamins?

A

fat-soluble

82
Q

What substance is most likely deficient? Sxs: corneal neovascularization, cheilosis (stomatitis), magenta-colored tongue

A

riboflavin (B2)

83
Q

Deficiency of vitamin D in children causes ___. In adults it causes ___.

A

rickets

osteomalacia

84
Q

Name the enzyme that requires folate as a cofactor. Identify the related pathway.

A

thymidylate synthase (thymidine synthesis)

85
Q

What is vitamin B5 a constituent of?

A

CoA

86
Q

Which form of vitamin A (cis or trans) acts as a cofactor for the conversion of opsin to rhodopsin?

A

Cis

87
Q

What test is used to determine a deficiency of vitamin B12?

A

Schilling test

88
Q

Where does 1-alpha hydroxylase activate the final bioactive form of vitamin D?

A

kidney

89
Q

What are the symptoms of pellagra?

A

diarrhea, dermatitis, dementia

90
Q

Name four clinical manifestations as a result of B2 deficiency.

A

angular stomatitis, cheilosis, corneal vascularization

91
Q

What is the general function of vitamin B2?

A

cofactor in oxidation and reduction

92
Q

What is vitamin B3 a constituent of?

A

NAD+, NADP+