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the amino acids with the longest biosynthetic pathways are the ________ amino acids
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essential
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what two amino acids are considered to be semiessental
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arginine and histidine
bc they are produced in the body, but not in sufficient quantities
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people that are decient in one or more amino acids go into what kind of a nitrogen balance
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negative
this means that they excrete more nitrogen from their bodies than they ingest
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when more protein is being synthesized than is being degraded a person is said to have a ___________ _________ __________
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positive nitrogen balance
this occurs in children or convalescing adults
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what is kwashiorkor?
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a disease that children in 3rd world countries when they are weened onto starchy protein-deficient diet
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what is the benefit to measuring 3-methylhistidine in the urine
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it is an indirect measurement of nitrogen balance. seen when muscle proteins are degraded at a high rate.
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what is one treatment of leukemic cells that inhibits their growth
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L-asparaginase
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pathways that produce acetyl CoA or acetoacetyl CoA are considered to be ________
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ketogenic
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alpha amino nitrogens can be removed by ________________ which is freely reversible.
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transamination
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what elevated serum level is a clinical indicator or marker of a myocardial infarction
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AST and AST/ALT
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what is a serum AST/ALT ratio that is low an indicator of
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liver disease
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how are ammonia levels kept low in the body
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by the liver by the urea cycle
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what are some of the symptoms of hyperammonemia
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tremors
slurred speech
coma
death
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many reactions of amino acid metabolism involve what vitamin
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pyridoxine (B6)
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transfer of CO2 groups to organic compounds (carboxylation) often requires the action of _________
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the B vitamin biotin
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one carbon groups are carried and transferred through the action of ____________
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tetrahydrofolate which is derived from the B vitamin folic acid (folate)
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severe folate deficiency causes _____________in which immature red blood cells accumulate in the bone marrow due to a block in their DNA replication
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megaloblastic anemia
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what is the name of the cancer chemotherapeutic agent that inhibits the enzyme dihydrofolate reductase
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methotrexate (an antifolate)
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diydrofolate reductase is required to synthesize ______________
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tetrahydrofolate
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a deficiency in tetrahydrofolate blocks the synthesis of ___________ bases and of _________nucleotides, thus ingibiting DNA repliaction which is why it is used as an anti-cancer drug
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purine
thymidine
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cells that are resistant to cancer drugs such as methotrexate have undergone gene amplification for the ____________________ _____________ gene
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dihydrofolate reductase
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what are two types of antifolates that are used as antibacterial antibiotics
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aminopterin
sulfa drugs (sulfanilimide)
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what is the function of sulfa drugs such as sulfnilimide?
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similar in structure to para-amino benzoic acid (PABA) which inhibits the incoporation of PABA into folic acid, thus producting a folate deficiency in bacteria
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what is the function of SAM
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biological methylation reactions:
creatine
methylated RNA and DNA
epinephrine
carnitine
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homocystinuria may play a role in what major diseases and symptoms?
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osteoporosis
atherosclerosis
lens dislocation
metal dysfunction
mental retardation
lethargy
thrombosis
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what can reduce the levels of homocysteine
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supplements of vit B6, B12, and folic acid
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what is the result of a vit B12 deficiency
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pernicious anemia
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how is B12 absorbed into the ileum
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intrinsic factor
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what is the danger of high folic acid supplimentation
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it can mask anemia and thus result in mental symptoms from those that have a vit B12 deficiency that leads to pernicioius anemia (megaloblastic anemia with neurological deterioration)
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what are the two main sources of Vit B12
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stomach of animal foods
baterial fermentation of plant products
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PKU is commonly caused by a genetic defect in the ___________ ______ structural gene or by a defect in the synthesis or regeneration of the _______ cofactor
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phenylalanine hydroxylase
biopterin
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why are the levels of phenylpyruvate/phenyllactate measured of all newborns?
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check for diagnosis of PKU to avoid mental retardation
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what is the second type of melanin fromed in red haired people called?
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pheomelanin
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albinism is most commonly caused by a genetic defect in the _________ structural gene
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tyrosinase
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what causes Parkinson's disease and how is it treated?
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caused by a lowered ability by the substantia nigra to synthesize dopamine
treated with DOPA
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what drug is given to Parkinson's Disease patients to counter the effects of DOPA outside of the Central nervous system
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carbidopa (bc it doesn't cross the blood brain barrier, but does inhibit DOPA decarboxylase)
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transaminases are ________________ dependend enzymes
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pryidoxal phosphate
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i thas been demonstrated that ammoniium intoxication leads to a depletion of the ________ pool
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ATP
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pyridoxal phosphate which is involved in many reations of amino acid metabolism is derived from ____________
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pryidoxine (vit B6)
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what is the MO of pyridoxal phosphate
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forms a Shiff base intermediate which acts as an electron sink, destabilizing the groups around the alpha carbon
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marginal folate deficiencies are responsible for the majority of ______________ cases which is why women take folate supplements before becoming pregnant
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spina bifida
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what do folates do with homocysteine and why is it important
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regenerate methionine
which then become SAM which does tons of stuff
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marginal deficiencies of B6, B12, and folic acid are risk factors for both _________ and ___________
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atherosclerosis
mental dysfunction
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a vit B12 deficiency will lead to an accumulation of folates in the form of __________________
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N-methyl-THF
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what are two symptoms of alkaptonuria
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urin turns black on studing due to oxidation of the homogentisic acid that accumulates
darkening of connective tissues and a form of arthritis
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pheomelanin (the melanin in red heads) is formed from what?
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cysteine resideus from glutathione
tyrosine
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what is the formation process of melanin
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tyrosine--> DOPA--> Dopaquinone---> Melanin
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what is used to treat thyperthyroidism?
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thiourea dn related compouds
(thyroid ablation or treatment with radioactive iodine, to partially destroy thyroid cells aae also used)
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