| Question |
Answer |
| why can't you measure uncongjugated bilirubin directly? |
it is still attached to albumin |
| what are the 10 essential amino acids? |
PVTTIMHALL (Phenylalanine, Valine, Tryptophan, Threonine, Isoleucine, Methionine Histidine, Arginine, Lysine, Leucine) |
| what are the only possiuble sources of essential amino acids? |
protein turnover and diet |
| what are some products of amino acids? |
purines, pyrimidines, porphyrins, and neurotransmitters |
| what is a positive or negative nitrogen balance? |
input>output; output>input |
| tyrosine is synthesized from what essential amino acid? |
phenylalanine |
| what is an example of a porphyrin? |
heme |
| carbon portions of amino acid degradation can be used to make what? |
fatty acids, ketones, glucose |
| alanine, aspartate, and glutamate are made from transamination of what? |
pyruvate, oxaloacetate, and a-ketoglutarate |
| where is arginine created? |
in the urea cycle |
| where does cysteine get its sulfur from? |
methionine |
| what are the 3 cofactors required for amino acid synthesis? |
pyridoxal phosphate (PLP), tetrahydrofolate, and tetrahydrobiopterin |
| what is pyridoxal phosphate (PLP) made from? |
B6 |
| in what 2 ways is nitrogen removed from amino acids? |
deamination and transamination |
| what is the main difference between deamination and transamination? |
deamination produces ammonia |
| aminotransferases are also called what? what do most aminotransferases require as a cofactor? |
transaminases; pyridoxal phosphate (PLP) |
| what are the roles of alpha-ketoglutarate and glutamate in transamination? |
amino acid gives its amino group to alpha-ketoglutarate to produce glutamate |
| what are the 2 important transaminases? what are their reversible products? |
ALT and AST; alanine<->pyruvate and oxaloacetate<->aspartate |
| if liver function is impaired, what will happen to albumin? |
it is also impaired |
| what does glutamate dehydrogenase do? |
it deaminates glutamate to produce alpha-ketoglutarate |
| glutamate and an extra ammonia form what molecule? what enzyme does this? |
glutamine; glutamine synthase |
| in the liver, glutamine is broken down into glutamate and an extra ammonia how? |
glutaminase |
| aside from glutamate, what other molecule can transport ammonia to the liver? |
alanine |
| what are the roles of pyruvate and ALT in alanine transporting ammonia to the liver? |
pyruvate will take the ammonia from glutamate via ALT, becoming alanine; it then transports the ammonia to the liver, where it gives the ammonia back to glutamate |
| which amino acids are ultimately degraded to pyruvate or TCA cycle intermediates, glucogenic or ketogenic? |
glucogenic |
| which amino acids are ultimately degraded to acetyl CoA or acetoacetate, glucogenic or ketogenic? |
ketogenic |
| which hormone promotes amino acid uptake and protein synthesis? which hormone induces ubiquitin synthesis to stimulate gluconeogenesis? |
insulin; cortisol |
| which 2 hormones stimulate amino acid uptake into the liver? |
cortisol and glucagon |
| what is a state of increased body fuel usage? |
hypercatabolic |
| what enzyme converts bicarbonate and ammonia into carbamoyl phosphate? which step is this in the urea cycle? |
carbamoyl phosphate synthase 1; first |
| which enzyme converts carbamoyl phosphate and ornithine into citrulline? which step is this in the urea cycle? |
ornithine transcarbomylase; second |
| arginine is essential for what process? |
growth only |
| in the urea cycle, you need what amino acid to make what tca cycle product? |
aspartate; fumarate |
| what are the two important products of the urea cycle? |
arginine and fumarate |
| where do the nitrogens come from in the urea cycle? |
1 from ammonia; 1 from aspartate |
| in the urea cycle, what molecule gets regenerated? |
ornithine |
| urea cycle regulation is primarily what kind of loop? |
feedforward |
| what synthesizes n-acetylglutamate (NAG)? |
glutamate or acetyl coa |
| what is n-acetylglutamate's effect on CPS1? |
allosteric regulator |
| what are the two possible fates of urea? |
filtered and urinated by kidney; broken down by bacteria into ammonia and put back through the cycle |
| what happens to BUN in kidney failure? liver failure? |
elevated; reduced |
| what is the common precursor of both ammonia and aspartate? |
glutamate |
| what is the most common urea cycle disorder? |
otc |
| otc is what kind of hereditary disease? |
x-linked |
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