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Nutrition Biochemistry Flashcards

1
Q

List the pancreatic digestive enzymes

A

zymogens
-trypsinogen, chymotrypsinogen, proelastase, procarboxypeptidases
active enzymes
-a-amylase, lipases, colipase, phospholipases, cholesterol esters, RNAase, DNAase
ions
-HCO3

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2
Q

What controls pancreatic enzyme secretion at each stage of digestion?

A

cephalic: ACh
gastric: ACh, gastrin
intestinal: CCK, secretin

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3
Q

What is pancreatic section of HCO3- controlled by?

A

ACh

Secretin

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4
Q

What enzymes are needed for the digestion of fat?

A

lipase, phospholipase, cholesterol esterases

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5
Q

Where and how are fat’s absorbed?

A

via micelles in the duodenum and jejunum

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6
Q

How are fats transported in the blood once they’re absorbed?

A

chylomicrons

VLDL

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7
Q

How does an endopeptidase work?

A

cleaves in the center of proteins & peptides

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8
Q

How does an exopeptidase work?

A

cleave from N or C terminal end of peptide and proteins

-carboxypeptiases, aminopeptidases

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9
Q

How are amino acids absorbed?

A

AA transporters

-tripeptidase and dipeptidase on epithelial cells break down into individual AAs for absorption

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10
Q

What enzymes are needed for the digestion of carbohydrates?

A

a-amylase

Di and trisaccharidases

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11
Q

How and where are carbohydrates absorbed?

A

via SGLT1 & GLUT 5 receptors in the duodenum and jejunum

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12
Q

What are the symptoms of lactase deficiency?

A

loss of function w/age

bloating and diarrhea due to bacterial degradation of lactose

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13
Q

How much of the world population is lactase deficient?

A

75%

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14
Q

What are the essential amino acids?

A

arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine

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15
Q

What are the essential fatty acids?

A

linoleic acid, linolenic acid

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16
Q

What are the calorie densities for the major nutrient groups?

A

(in kcal/g)

carbs: 4
proteins: 4
fat: 9
alcohol: 7

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17
Q

What percentages of each nutrient makes up dietary goals?

A

45-65 carbs
10-35 protein
20-35 fat

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18
Q

Where are the 2 protein storing compartments?

A

somatic protein-skeletal muscle stores

visceral protein-visceral organ stores

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19
Q

What is marasmus?

A 
severe reduction in caloric intake
>60% body wt reduction
depletion of somatic protein compartment
albumin normal
growth retardation
anemia
immunodeficiency
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20
Q

What is kwashiorkor?

A

more severe than marasmus
protein deprivation greater than caloric deprivation
can be due to malabsoprtion or chronic protein loss
loss of visceral protein stores
hypoalbuminemia
sparing muscle mass

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21
Q

What populations does protein malnutrition occur in in the US?

A

chronically ill, hospitalized, cachectic cancer patients, AIDS

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22
Q

What are complications from protein energy malnutrition?

A

infeciton
impaired wound healing
sepsis
death after surgery

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23
Q

What is obesity?

A

excessive body weight (BMI >30)

overweight BMI 25-29.9

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24
Q

What are medical complication of obesity?

A 
metabolic syndrome/type 2 diabetes
cardiovascular morbidity
cholelithiasis
cancers
pulmonary embolus/DVT
obstructive sleep apnea
hypoventilation syndorme
osteoarthritis
steatosis
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25
Q

How many people in the US are obese?

A

> 20%

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26
Q

What are the water soluble vitamins?

A

Bvitamins
-thiamne (B1), Riboflavin (B2), Niacin (B3), Pantothenic acid, biotin, folate (B9), B12, B6 (pyridoxine, pyridoxal, pyridoxamine)
Vitamin C

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27
Q

What are the fat soluble vitamins?

A

A (retinol, carotenes)
D (cholecalciferol)
E (tocopherois)
K (phlloquinones)

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28
Q

Features of Thiamine/Vitamin B1

A

absorbed in the duodenum and jejunum
non-toxic
excess is excreted, stores depleted in 14 days
active form is thiamine pyrophosphate

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29
Q

What are the functions of B1/thiamine?

A

cofactor for pyruvate dehydrogenase
cofactor in pentose phosphate pathway
maintains neural membranes and normal nerve conduction

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30
Q

What are sources of thiamine?

A

pork, whole grains, fortified breads and cereals, legumes and nuts

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31
Q

Features of thiamine/B1 deficiency?

A

extremely common in alcoholics
polyneuropathy “dry beriberi”
dilated cardiomyopathy “wet beriberi”
wernicke korsakoff syndrome

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32
Q

How is thiamine B1 deficiency treated?

A

banana bag

oral supplementation

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33
Q

What is wernicke-korsakoff syndrome?

A

aka wernicke encephalopathy
reversible, opthalmoplegia, confustion/disorientation, nystagmus, ataxi
has a chronic stage-korsakoff syndrome

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34
Q

What is korsakoff syndrome?

A

irreversible/chronic stage of wernicke-korsakoff syndrome
memory disturbances, confabulation
perivenricular and mammilary body hemorrhage/necrosis

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35
Q

Features of pantothenic acid/Vitamin B5?

A

absorbed in the duodenum
excess excreted, very little stored
active form is coenzyme A
-acyl carrier protein function, for fatty acid synthesis

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36
Q

Sources of pantohenic acid/B5?

A

wide spread in food

esp: whole grains, meats, fish, poultry

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37
Q

What is vit B5/pantothenic acid deficiency/Toxicity frequency?

A

deficiency-very rare

toxicity-excess excreted, no symptoms

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38
Q

Features of riboflavin/B2 function?

A 
absorbed in the duodenum and jejunum
mostly exreted
active forms (FMN & FAD)
functions as an electron carrier (complex dehydrogenases, citric acid cycle to electron transport chain)
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39
Q

Sources of riboflavin/Vit B2?

A

milk, milk products, eggs, meat, fish and whole grains, fortified breads and cereals, nuts and legumes

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40
Q

What are the symptoms or B2/riboflavin deficiency?

A

rare except in alcoholics
cheilosis (scaling and fissures at the corners of the mouth)
angular stomatitis (inflammation at the corner of the mouth)
glossitis (inflammation of the tongue-bald tongue)
dermatitis

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41
Q

Features of vitamin B3/niacin

A

absorbed in the duodenum and jejunum
excreted, not stored
active forms: NADH/NAD+, NADPH/NADP+

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42
Q

What is the function of NADH?

A

generated during degradation of carbohydrates, fats, amino acids and nucleic acids
carries electrons from the citric acid cycle to the electron transport chain

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43
Q

What is the function of NADPH?

A

generated by glucose-6-phosphate dehydrogenase in the pentose phosphate shunt
used in synthesis reactions for carbohydrates, fats, amino acids and nucleic acids

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44
Q

What are sorces of B3/niacin?

A

meat, fish, milk, eggs, whole grains, fortified cereal and breads, nuts legumes

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45
Q

What are the symptoms of niacin/vit B3 deficiency?

A

pellagra
uncommon except in alcoholics and impovershed
dermatitis (sun exposed skin), diarrhea, dementia

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46
Q

Niacin/B3 toxicity symptoms?

A

flushing
gastric irritation
rashes

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47
Q

Biotin/B7 features?

A

absorbed in duodenum and jejunum
active form: biotin bound to carboxylase
most excreted, not stored

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48
Q

What is the function of B7/Biotin?

A

carboxylase cofactor
-pyrubate carboxylase
acetyle CoA carboxylase

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49
Q

What are sources of B7/Biotin?

A

liver, milk, eggs, fish, peanuts, chocolate, nuts, whole grains, legumes
synthesized by intestinal bacteria

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50
Q

What are symptoms of biotin/B7 deficiency?

A

rare, usually in elderly
can occur by binding biotin to avidin in raw egg whites
biotinidase deficiency-inability to convert dietary derived biocytin to free biotin
porr growth, neuro disorders in infants
dermatitis and hair loss in adults/kids

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51
Q

B7 toxicity?

A

no, excreted

52
Q

Features of pyridoxine/B6?

A 
absorbed in the jejunum and ileum
small amount stored, most excreted
active form: pyridoxal phosphate
coenzyme involved in
-aminoacids degradation/conversion to other important molecules
-glycogen degradation
-porphyrin synthesis
53
Q

Pyridoxine/B6 sources?

A

beans, nuts, legumes, meats, eggs, fish, whole grains, fortified grains & cereals

54
Q

Symptoms of B6/pyridoxine deficiency?

A 
cheilosis
angular stomatitis
glossitis (bald tongue)
dermatitis
peripheral neuropathy
microcytic hypochromic anemia
confusion and irritability
55
Q

causes of B6/pyridoxine deficiency?

A

alcoholics and kidney failture pts

causes by isoniazid for tuberculosis

56
Q

Symptoms of B6/pyridoxine toxicity?

A

peripheral sensory neuropathy

57
Q

What are the hematopoeitic vitamins?

A

folate/B9

Cobalamin/B12

58
Q

What are features of folate/B9?

A

absorbed in the duodenum, jejunum and ileum
most excreted, small amount stored
active form: tetrahydrofolate
carrier of 1 carbon units for: purine synthesis, dTMP synthesis, conversion of homocysteine to methionine for S-adenosylmethionine synthesis

59
Q

Sources fo folate/b9?

A

beans, legumes, citrus fruits, dark green leafy vegetables, whole grains, fortified grains, cereals, meat

60
Q

Causes of folate/b9 deficiency?

A

inadequate intake
associated w/antifolate tx (methotrexate, 5FU)
prevent w/ supplementation

61
Q

Symptoms of folate/B9 deficiency?

A

megaloblastic anemia
leukopenia
fetal neural tube defects (spina bifida occulta–> anencephaly)
glossitis

62
Q

What are some features of cobalamin/vit b12?

A

absorbed w/intrinsic factor in ileum
stored in liver (stores last ~2 years)
active form is cobalamin

63
Q

What is the function of b12/cobalamin?

A

methionin synthase &
methyl malonyl coenzyme A mutatse rxns
myelination

64
Q

Sources of B12/cobalamin?

A

meat, shellfish, fish, eggs, milk, cheese, yogurt

65
Q

What are causes of B12 deficiency?

A 
impaired absoprtion (IF def, ileal resection)
decreased intake
tapeworm
66
Q

What are the symptoms of B12 deficiency?

A

megaloblastic (perniciuos) anemia
neural tube defects
subacute combined neural degeneration (sensory ataxia, parasthesias, spastic paraparesis)

67
Q

What vitamines have antioxidant and post-translational modication functions?

A

C, E, B-carotene (provitamin A)-antioxidant

C, K-post translational modication

68
Q

What are some features of VitC/Ascorbate?

A

absorbed in the jejunum and ileum
excreted, not stored
active form is ascorbic acid (ascorbate)

69
Q

What is the function of vitamin C?

A

Antioxidant-reduces ROS, oxidized vit E
Cofactor of enzymes that reduce metal ions
post translational modification of proteins-collagen
synthesis of neurotransmitters and hormones

70
Q

What are sources of vitamin C/ascorbate?

A

ALL fruits and vegetbles

highest in citrus fruits, strawberries, green peppers, broccoli, green leafy vegetables, tomatoes and potatoes

71
Q

What occurs with vitamin C deficiency?

A

scury

  • easy bruising
  • corkscrew hairs
  • petechial hemorrhages
72
Q

What occurs with vitamin C toxicity?

A

usefulness for high levels for colds controversial, slowly reduce high levels

73
Q

What are some features of tocopherol/Vitamine E?

A

most active form: a-tocopherol
absorbed via micelles in duodenum and jejunum
distributed via chylomicrons
stored in adipose tissue, liver, muscle

74
Q

What is the function of vitamin E/tocopherol?

A

antioxidant-scavenges free radicals

75
Q

What are good sources of vitamin E?

A

vegetable oils, liver and eggs

76
Q

What occurs wtih vitamin E deficiency?

A

irritability, edema, hemolytic anemia

uncommon except w/malabsorption syndromes, TPN and premature infants

77
Q

Is there vitamin E toxicity?

A

no

78
Q

What is a pharmacological use of vitamin E?

A

Alzheimer’s disease progression inhibitor

79
Q

What are some features of vitamin K/phylloquinones?

A

absorbed from micelles in duodenum, jejunum and ileum
distributed via chylomicrons
stored in the liver
active form: K1

80
Q

What are some functions of vitamin K/phylloquinones?

A

post translational modification-cofactor for vitamin K dependent gamma-carboxylase
-cpag factors II, VII, IX, X, proteins S, C, bone calcium binding proteins
modifeid GIa residue binds calcium and localizes coagulation proteins on activated platelets

81
Q

What are good sources of vitamin K/phylloquinones?

A

green vegetables, spinach, kale, peas, cauliflower and cabbage

82
Q

What are features of vitamin K/S deficiency?

A

rare except w/warfarin tx, malabsoprtion syndrome, broad spectrum Abx, lack of gut flora in neonates, chronic bleeding
sx: bleeding/defective clotting ( bruising, hematomas), hemorrhagic disease of the newborn

83
Q

What are features of vitamin K/S toxicity?

A

shortened bleeding time

food as source no toxicity

84
Q

What are some features of vitamin A/carotenes/retinoids?

A

absorbed via micelles in the duodenum and jejunum
distributed via chylomicrons
stored in liver stellate cells or as retinyl esters (retinol)

85
Q

What are the functions of vitaminA?

A

Bcarotene-antioxidant, vit A precursor
retinol-major transport form
11-cis-Retinal (retinaldehyde)-vision
Retinoic acid (all-trans, 9-cis)-regulation of retinoid responsive gene expression (epithelial cell function, mucous cell function, immunity, reproduction)

86
Q

How does 11-cis-retinal aid with vision?

A

binds to rhodopsin in rods and to the cone pigments in cones
difference in minding to the 3 cone pigments results in absorption of different wavelengths of light
light absorbed by 11-cis retinal bound to rhodopsin in the rods and to the cone pigments in the cones of the retina, light converts 11-cis-ratinal into all-trans retinal, the g coupled receptor, transducin, in the rod and cone membranes changes conformation and acrivates the G-protein leading to activation of a phosphodiesterase, cleavage of cGMP closes the cGMP coupled iron channel and sending a signal to the brain

87
Q

What are good sources of vitamin A?

A 
Bcarotene: green leafy vegetables, other intensely colored vegetables (carrots, sweet potatoes, red peppers)
Retinyl Esters (RE): eggs, meat, dairy
88
Q

What is the result of a vitamin A deficiency?

A

impaired vision-night blindness
squamous metaplasia (mucus cells, epithelial cells-xeropthalmia, xerosis, bitot’s spots [keratin debris], corneal ulceration, keratomalacia, follicular hyperkeratitis)
renal, urinary calculi
predispostion to pumonary infections and diarrhea

89
Q

What occurs from vitamin A toxicity?

A

B carotene-non toxic, yellow skin due to fat depostion
Retinol-toxic at high levels (blurred vision, abd pain, peeling of skin, hair loss, headache, dizziness, vomiting, bone pain and deformities)
-extremely toxic at very high levels-death
Retinal-toxic at high levels esp to the retina
Retinoic acid-toxic at levels used to treat acne (teratogenic, peeling of skin)

90
Q

What are some key features of VitaminD/Calciferols?

A

dietary-D3, animals; D2, plants
hormone-D2-sunlight
Active: 1,25 dihydrovitamin D (cholecalciferol)
absorbed via micelles in duodenum, jejunum and ileum
distributed via chylomicrons
stored in the liver

91
Q

what is the function of vitamin D?

A

controls expression of vit D responsive genes
maintenance of normal calcium and phosphate plasma levels
controls cell cycle arrest, apoptosis, immune suppression, anti-inflammation, differentiation

92
Q

What are good sources of vitamin D?

A

cheese, butter, margarine, fortified milk, fish, fortified cereal

93
Q

What initiates synthesis of vitamin D from 7-dehydrocholesterol?

A

sunlight

94
Q

What are predisposing conditions for vitmain D deficiency?

A

inadequate synthesis or dietary deficiency
decreased absorption
metabolic errors
end organ resistance
phosphate depletion
less severe deficiencies assoc w/thyroid changes, cancer, CV disease, cognitive impairment, parkinson disease

95
Q

What occurs in kids & adults with vitamin D deficiency?

A 
kids-ricket's
-bowed legs, frontal bossing, pigeon breast
adults-osteomalacia
-soft, painful, bendable bones
-osteoporosis
-dowager's hump
96
Q

What occurs in vitamin D toxicity?

A 
diarrhea
dermatitis
headache
nausea
anorexia
calcification of soft tissue
kidney stones
decalcification of bones
97
Q

Which vitamin has a special purpose to help with vision?

A

vitamin A

98
Q

Which vitamins affect gene expression?

A

vitmain A, vitamin D and other vitamins

99
Q

Which vitamins are antioxidants?

A

vitamin C, viamin E and carotene (provitamin A)

100
Q

Which vitamins do posttranslational modification?

A

vitamin K, vitamin C

101
Q

Which vitamins are substrate carriers?

A

thiamine, pantothenic acid

102
Q

Which vitamins are electron transfer molecules?

A

riboflavin, niacin

103
Q

Which vitamins are substrate binding?

A

biotin, pyridoxine

104
Q

Which viamins have a hematopoeitic effect?

A

folate, vitamin B12

105
Q

What are some key features of iron?

A

absorbed in the 2+ form in the duodenum and ileum

stores w/ferritin and hemosiderin in the liver, spleen and bone marrow

106
Q

What are good sources of iron?

A

meats, fish, shellfish, lentils, beans,seeds, tofu, spinach

107
Q

What are functions of iron?

A

in heme
iron-sulfer complexes required for aconitase in citric acid cycle and electorn transport chian
enzyme co-factor

108
Q

What occurs with iron deficiency?

A 
hypochromic microcytic anemia/IDA
glossitis
angular stomatitis
cheilosis
impaired cognition and work capacity
immune deficiency
109
Q

What occurs with iron toxicity?

A

hemochromatosis-abnormal deposits in liver, pancrease, heart and skin

110
Q

where is zinc absorbed?

A

absorbed in jejunum

111
Q

What are good sources of zinc?

A

oysters/shellfish
meat
plants at lower levels

112
Q

What are the functions of zinc?

A

component of metabolic enzymes (metalloproteases, oxidases)
gene expression-Zn finger proteins
spermatogenesis
skin maintenance and wound healing

113
Q

What occurs w/zinc deficiency?

A

Rare
rash
anorexia
diarrhea
growth retardation
depressed wound healing and immune response
infertility due to inhibition of testosterone synthesis

114
Q

What populations is zinc deficienc more common in?

A 
pts w/
DM
malabsoprtion syndromes/chronic diarrhea
renal disease/dialysis
IV feeding
major burn patients
inborn error of Zn absorption
115
Q

What are key features of iodine?

A

absorbed in the stomach
found in salt water fish and shellfish, iodized salt
is a component of thyroid hormones

116
Q

What occurs in iodine deficiency?

A

goiter
cretinism
myxedema

117
Q

What is myxedema?

A

adults w/ dry skin, swelling of skin around nose and lips
mental deterioration
subnormal bsal metabolic rate

118
Q

What occurs with iodine toxicity?

A

goiter

thyrotoxicosis

119
Q

What are some key features of copper?

A

absorbed in the stomach and duodenum

found in liver, shellfish, chocolate, nuts and seeds

120
Q

What are some functions of alzheimers?

A

oxidation reactions including electron transport-cytochrome C oxidase, tyrosinase
neurotransmitter regulation-dopamine B-oxidase
antioxidants-superoxide dismutase
collagen crosslinking enzymes-lysyl oxidase
development of vascular and skeleton structures and the CNS

121
Q

What occurs in copper deficiency?

A 
microcytic hypochromic anemia
muscle weakness
neurological defects
abnormal collagen crosslinks leading to bleeding
neutropenia
122
Q

What occurs in copper toxicity?

A

usually genetic
neurological defects
corneal copper deposits

123
Q

What are some key features of fluoride?

A

absorbed in the stomach
found in water and toothpaste
needed by teeth to prevent dental carries

124
Q

What are symptoms of fluoride toxicity?

A

mottled tooth enamel

125
Q

What are key features of selenium?

A

absorbed in the duodenum
found in plans grown in selenium containing soil, fish and shellfish
component of glutathione peroxidase, antioxidant w/vitaminE and regulates thyroid hormone action

126
Q

What occurs in selenium deficiency?

A

myopathy

cardiomyopathy (kids)

127
Q

What occurs in selenium toxicty?

A 
hair and nail damage nad oss
tooth decay
neuropathy
liver cirrhosis 
depression

GI (20 decks)

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