When body cells need more iron, the number of transferrin receptors on the cell
ID: 97145 • Letter: W
Question
When body cells need more iron, the number of transferrin receptors on the cell increases. decreases. remains unchanged. Which of the following factors increases iron absorption? high intakes of zinc high stores of iron low gastric acidity increased need for iron A deficiency of dietary iodide is characterized by osteoporosis. goiter. dental caries. decreased glucose tolerance. Which factor limits absorption of dietary calcium? Phytic acid Chronic diarrhea Tannins in tea Vitamin D deficiency All of these choices are accurate.Explanation / Answer
4. A. Increase.
Transferrin receptor is a carrier protein for transferrin. It is needed for the import of iron into the cell and is regulated in response to intracellular iron concentration. It imports iron by internalizing the transferrin-iron complex through receptor-mediated endocytosis. Low iron concentrations promote increased levels of transferrin receptor, to increase iron intake into the cell.
5. D. Increased need for iron
Absorption is increased in iron deficiency and reduced in iron overload. High intake of zinc and gastric acidity have no effect on iron absorption.
6. B. Goiter
A goiter is a swelling in the neck resulting from an enlarged thyroid gland. It is associated with not properly functioning of thyroid. Over 90% of goitre cases are caused by iodine deficiency.
7. E. All of these choices are accurate
Phytic acid has a strong binding affinity to important minerals, such as calcium, iron, and zinc, and the binding of calcium with phytic acid is pH-dependent.
Antimotility agents are the most effective for the treatment of chronic diarrhea. Attention should be paid to replacing any mineral and vitamin deficiencies, especially calcium, potassium, magnesium and zinc.
The tannins in tea increasing rheumatoid arthritis risk by causing a calcium-phosphorus imbalance.
Vitamin D serves several important functions in the body. These include promoting calcium absorption and maintaining normal calcium level.
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