Term
| A condition that could cause a negative Nitrogen balance (when there is more output than input) |
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Definition
| Starvation and some disease states |
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Term
| A condition that would cause a positive nitrogen balance( more input than output) |
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Definition
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Term
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Definition
| Continuous degradation and resynthesis of body protein – rate of protein synthesis is sufficient to replace the protein that is degraded. |
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Term
| 2 wyays proteins are degraded |
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Definition
1. ubiquitin-proteosome-used for intercelllar degradation-requires ATP
2. Lysosmes-used for extracellular degradation |
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Term
| Which type of AAs are most reactive/least reactive? |
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Definition
charged(most reactive)
nonpolar(least reactive) |
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Term
| What are the 3 AA classifications? |
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Definition
| Essential, Nonessential, and conditionally essential |
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Term
| What are essential AAs and give examples. |
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Definition
essential in the diet - obtained from food
lysine, isoleucine, leucine, tyrosine, valine, tryptophan, phenylalanine, methionine, histidine, (arginine)
LIL TV To PM, HA |
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Term
| What are nonessential AA? |
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Definition
| AAs that are synthesiszed by the body |
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Term
| What are some conditionally essential AAs? |
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Definition
AAs that become essential under certain circumstances.
Arginine (Arg, R): not required by adults; essential for growth (needed in young children)e.g. kidney disease
Cysteine (Cys, C): becomes essential if methionine supply is inadequate – sulfur group obtained from methionine
Tyrosine (Tyr, Y): derived from the essential AA phenylalanine |
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Term
| Where does cysteine get its sulfur group? |
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Definition
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Term
| Which AA is derived from the eesential AA phenylalanine? |
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Definition
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Term
| Two ways an AA can be classified based on the fate of the C skeletons |
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Definition
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Term
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Definition
| carbon skeletons can be converted to glucose precursor – produce pyruvate or intermediates of the TCA cycle |
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Term
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Definition
| carbon skeletons can be converted directly to acetyl CoA and acetoacetate |
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Term
| What are the only 2 strictly ketogenic AA |
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Definition
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Term
| What are the 3 main components of the digestive system that produces enzymes break down proteins? |
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Definition
| stomach, pancreatic, intestinal |
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Term
| What enzymes are produced by the stomach that break down proteins |
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Definition
| HCl and pepsinogen(pepsin) |
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Term
| What is the fuction of digestive enzymes in the stomach? |
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Definition
| To begin the process of breaking down proteins. In the stomach proteins are converted to oligopeptides |
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Term
| How is pepsinogen activatied? |
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Definition
| It is activated by HCL and can be autoactivated by other activated pepsinogen |
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Term
| What are the name of the enzymes produced by the pancreas? |
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Definition
| HCO3, trypsin, chymotrypsin, elastase, carboxypeptidases A and B. |
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Term
| Which pancreatic enzymes are considered endopeptidases? |
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Definition
| trypsin, chymotrypsin, and eleastase |
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Term
| What does carboxypeptidase A cleave? |
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Definition
| hydrophobic AA at the C terminus |
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Term
| What does carboxypeptidase B cleave? |
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Definition
| Arg and Lys at the C terminus |
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Term
| What does elastase cleave? |
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Definition
| the C end of Ala, Gly, and Ser withon the peptide |
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Term
| What does chymotrypsin cleave? |
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Definition
| Phe, Typ, Tyr, Leu at the C end within proteins |
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Term
| What does trypsin cleave? |
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Definition
| Arg and Lys ay the C end within a polypeptide |
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Term
| WHat cleaves Phe, Tyr, Glu, Asp? |
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Definition
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Term
| What cleaves the amino peptide of a protein? |
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Definition
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Term
| Converts peptides to di and tri peptides in the small intestine |
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Definition
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Term
| Converts di and tri AA to AA |
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Definition
| aminopeptidases in the brush border |
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Term
| What is the role of CCK and secretin? |
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Definition
| its produced by the muscosal cells in the intestine and is activated by HCL. it then cativates the 1st pancreatic enzyme to be activated, trypsin. |
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Term
| What causes the activation of trypsinogen |
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Definition
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Term
| What enzyme activates chymotrypsin, proeleastase, and procarboxypetidase |
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Definition
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Term
| By what mechanism is protein metabolism hindered for a person with cystic fibrosis? |
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Definition
Caused by drying and thickening of pancreatic secretions which blocks pancreatic ducts that normally carry pancreatic enzymes to small intestines
Pancreatic enzymes unable to enter intestinal lumen to digest dietary proteins.
This causes protein malabsorption, bulky foul smelling oily stools, poor growth & malnutrition. |
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Term
| What is the treatment for pancreatitis and surgical removal of the pancreas? |
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Definition
| treat with oral pancreatic enzymes |
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Term
| How is the Na-AA cotransporter specificity determined? |
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Definition
| there are 6 different types and the the specificity is based on the R group ( basic, acidic, ....) |
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Term
| When [AA] is low in the intestine how is it taken from circulation? |
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Definition
| the AA transporter is bidirectional so when [AA] gets too low it is passively transported from the portal vein. |
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Term
| WHy is AA absorption abnormal in a person with cystinuria? |
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Definition
Common genetic error of AA transport.
Cause a Defect in transport system responsible for the uptake of cystine and the dibasic AAs cystine, ornithine, arginine & lysine (COAL).
High levels of these AA in urine, but not in the blood. |
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Term
| Other than abnormal AA absorption what other symptom is found in Cystinuria and how is it treated? |
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Definition
Precipitation of cystine form kidney stones, block urinary tract, bleeding, severe pain.
-Treat with large water intake and drugs to increase urine pH. |
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Term
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Definition
Genetic error of AA transport.
Defective transport of neutral AAs (e.g. tryptophan), intestinal malabsorption and low kidney reabsorption (aminoaciduria).
Loss of tryptophan, precursor of niacin.
-Pellagra-like rash and some neurological symptoms
-Treat with niacin (nicotinic acid). |
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Term
| What is the fate of ansorbed AA? |
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Definition
57% oxidized in liver
23% pass through liver intact to muscle via blood (branched-chain AAs)
14% to synthesis of liver proteins
6% to synthesis of plasma proteins
Excess AA not stored - rapidly degraded |
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Term
| Where are most branched AAs metabolized? |
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Definition
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Term
| What is the fate of Nitrogen during AA break down? |
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Definition
N is converted to asparatate(which is a zwitterion at physiologic pH)
or
ammonuim (NH4) will enter the urea cycle and be converted urea |
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Term
| What is the fate of Carbon in AA catabolism? |
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Definition
the carbon can be broken down further to CO2 and H2O to produce energy.
or
it can be converted to glycogen and stored. |
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Term
| the 2 AA that do not undergo aminotransferase reaction |
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Definition
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Term
| WHat coenzyme is required for aminotransferase reaction as a cofactor |
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Definition
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Term
| Describe to alanine aminotransferase reaction |
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Definition
| the NH3+ on alanine in transferred to alpha ketoglutarate to form glutamate and alpha keto acid. This reaction is catalyzed by alanine aminotransferase |
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Term
| The strictly ketogenic AA |
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Definition
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Term
| The glucogenic and ketogenic AAs |
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Definition
PITTT
phenyalanine
isoleucine
trytophan
threonine
tyrosine |
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