Phosphorus Flashcards
Phosphorus is second only to calcium as what?
the most abundant what inorganic element in the body
How much phosphorus is in the body?
about 700 grams
What is the best source of phosphorus?
animal products
What enzyme is needed to free phytate bound phosphates?
phytase
In bone phosphorus is found complexed with calcium as part of what bone mineral?
hydroxyapatite
How does PTH, clacitriol, and calcitonin affect phosphorus levels?
PTH - resporption of bone phosphate and excretion of phosphorus
cacitriol - promotes phosphate absorption in small intestine
calcitonin - prevents bone phosphate resporption
Phosphorus plays what 3 roles in regard to nucleotide/nucleoside phosphates?
- structural role - sugar phosphate backbone
- energy storage/transfer - high-energy phosphate bonds
- second messenger
How is the potential E of these high-energy phosphate bonds released?
hydrolysis of the phosphoanhydride bond
Phosphorus acts as a second messenger by activating which kinases?
- PI 4,5-bisphosphate
- Inositol 1,4,5-trisphosphate
How does phosphorus act as the main intracellular buffer?
Phosphorus removes free hydrogen ions and increase pH
What is the most important acid buffering organ in the body?
kidney
What hormones increases phosphate excretion?
PTH
What can cause hypophosphatemia?
excessive amounts of antacid ingestion
Exsessive phosphorus intake can inhibit what enzyme, which then reduces the absorption of what mineral?
inhbited 1-hydroxyase leads to reduced calcium absorption
