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28 Cards in this Set
- Front
- Back
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What is the required amount per day of protein needed by an adult? |
45 g/day |
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How much protein per day do young children need? (per kg) |
4 g/day/kg |
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Where does protein in stool come from? |
Bacteria and desquamated cells |
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Where is protein "stored" in the body? |
Muscle (first tissue to be broken down) |
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What food source is considered of complete protein? |
Animal proteins |
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Which peptidases act on interior bonds of polypeptides? |
Endopeptidases = interior bonds
exopeptidases = exterior bonds |
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What percent of protein does pepsin hydrolyze? |
~15% |
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At what pH is pepsin inactivated? |
pH > 4.5 |
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In what part of the intestines are brush border peptidases and carboxypeptidases concentrated? |
Proximal jejunum |
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Are single amino acids absorbed more quickly than dipeptides? |
No, dipeptides are |
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What ions are necessary for the absorption of amino acids and peptides? (2) |
Na+ & H+ |
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Describe how peptides are absorbed? |
Na+/K+ ATPase drives (3Na out / 2K in) the sodium gradient; Na+/H+ antiporter kicks hydrogen ion out; H+/di-&tripeptide symporter brings peptides and proton in. |
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In what case is pinocytosis of larger peptides is important? |
Absorbing antibodies in fetuses and infants |
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Would low levels of sodium in lumen inhibit absorption? |
Yes (as in hyponatremia) |
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What dysfunction of protein digestion/absorption is characterized by high protein in the feces? |
creatorrhea |
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What causes protein absorption problems with CF? |
pancreatic enzymes are absent |
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What is nontropical sprue? |
Celiac disease: no brush border, microvilli, nor membrane bound enzymes (gluten allergy) |
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What is Hartnup's disease? |
Hereditary deficiency in transport of neutral amino acids |
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What percentage of water that is secreted into the gut lumen is absorbed? |
70-90% |
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What is paracellular transport? |
Substances moving along concentration and electric gradients around cells and straight into the basal lamina |
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What chemical can knockout the Na+/K+ ATPase? |
Ouabain |
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What ion is actively secreted into the lumen of the colon?
What hormone upregulates this? |
K+
Aldosterone |
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What protein binds calcium in the intestines along the brush border? |
Calcium-binding protein (CBP) |
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What hormone and vitamin regulate calcium absorption of the gut? |
PTH & Vitamin D |
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What ion of iron is absorbed into the enterocyte? |
Fe2+ |
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What enzyme helps store iron in the enterocyte?
When is this complex moved to circulation? |
Transferrin
When iron is needed |
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What enzyme binds iron and holds it in the enterocyte to be sloughed off with the cell? |
Ferritin |
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Where does transferrin first meet iron-II? |
In the lumen |
