Biochem Diseases Flashcards
In what benign condition do you see excretion of large amounts of fructose after ingestion?
Essential fructosuria (fructokinase deficiency)
What drug blocks the F0 portion of the adenosine triphosphatase (ATPase) system of the ETC?
oligomycin
What drug blocks the ETC by attahing itself to K+ for pasage through the membrane, negating the charge gradient?
Valinomycin
A patient who presents with cardiomegaly and hepatomegaly has what glycogen storage disease?
Pompe’s disease (lysosomal glucosidase def)
What hormone is activated in adipose tissue when blood glucose levels decrease?
Hormone-sensitive lipase
What disease is produced by a deficiency in the enzyme tyrosinase?
Albinism (tyrosine is converted to melanin by the enzyme tyrosinase)
What 2 enzymes are blocked by lead?
- ALA dehydratase
2. Ferrochelatase
What enzyme is blocked by allopurinol?
Xanthine oxidase (suicide inhibitor)
What 3 organs are used to produce vit D?
Skin
Liver
Kidney
Lack of what enzyme can lead to wernicke-korsakff synd through lack of activity in the HMP shunt
TPP
Which enzyme is deficient in PKU?
phenylalanine hydroxylase
Which enzyme is deficient in alcaptonuria?
Homogentisic acid
In a diabetic patient, glucose is converted to what by aldose reductase?
Sorbitol (resulting in cataracts)
Which enzyme is deficient in a patient who presents with: liver damage and severe hypoglycemia?
Aldolase B (hereditary fructose intolerance)
Which enzyme is deficient in a patient who presents with: jaundice, vomiting, lethargy, cataracts, galactosemia, and galactosuria?
Galactose 1-phosphate uridyltransferase
What disease presents with weakness and cramps on exercise without an inc in blood lactate levels?
McArdle’s disease (muscle glycogen phosphorylase def)
What disease presents with an enlarged liver and kidneys, dwarfism, hypoglycemia, acidosis, and hyperlipidemia?
VonGierke’s disease (Glucose-6-phosphatase deficiency)
Deficiency in the liver glycogen phosphorylase enzyme is known as what?
Hers disease
What causes the lysis of RBC by oxidizing agents in a glucose-6-phosphate dehydrogenase deficiency?
Lack of glutathione peroxidase activity results in dec in NADPH production, leaving glutathione in the reduced state.
What disease presents with hepatomegaly and a normal EKG?
glycogen storage disease, type III
Forbes disease, Cori disease
What enzyme is blocked by disulfiram?
Aldehyde dehydrogenase
What 2 enzymes are Vit B12 dependent?
- Homocysteine methyl transferase
2. methylmalonyl CoA transferase
What enzyme is deficient in a patient 2 years of age or younger who presents with vomiting, lethargy, coma, hypoketosis, and hypoglycemia following a fast of more than 12 hours?
medium chain acyl dehydrogenase
What form of alcohol did a patient drink if he becomes blind as a result?
Methanol (wood alcohol)
What type of damage to the kidneys is caused by drinking ethylene glycol (antifreeze)?
Nephrotoxic oxylate stones
What is the order of fuel use in a prolonged fast?
- glucose from liver glycogen
- glucose from gluconeogenesis
3, body protein - body fat
What enzyem deficiency will rsult in an increase in blood ammonia and increase in uracil and orotate concentrations in both the blood and urine?
Ornithine transcarbamolyase (OTC) deficiency - also called ornithine carboamyltransverase (OCT) def
What aa is the precursor of the following substances: serotonin
tryptophan
What aa is the precursor of the following substances: GABA
glutamate
What aa is the precursor of the following substances: histamine
histidine
What aa is the precursor of the following substances: creatine
glycine/arginine
What aa is the precursor of the following substances: NAD
tryptophan
What aa is the precursor of the following substances: N2O
arginine
What enzyme deficiency will result in an increase in blood ammonia, but no increase in uracil concentrations?
Carbamoyl-phosphate synthetase
What are the 3 diseases of sphingolipids?
- Niemman-Pick disease
- Gauger disease
- Tay-Sachs disease
What type of jaundice is seen in Rotor’s syndrome?
Conjugated (direct) hyperbilirubinemia
What enzyme is blocked by hydroxyurea?
ribonucleotide reductase
What enzyme is deficient in hereditary protoporphyria?
Ferrochelatase
What enzyme is blocked by 5-FU
thymidylate synthetase
What disease has a genetically low level of UDPglucuronate transferase, resulting in elevated free unconjugated bilirubin?
Gilbert syndrome
What form of bilirubin can cross the BB?
unconjugated free bilirubin
What enzyme is blocked by methotrexate/trimethoprim?
DHF reductase
What type of jaundice is seen in Dubin-Johnson syndrome?
Conjugated (direct) hyperbilirubinemia (transport defect)
What form of bilirubin is carried on albumin?
unconjugated (indirect)
What disease is there a genetic absence of UDPgulcuronate transferase, resulting in inc in free unconjugated bili?
Crigler-Najjar syndrome
What enzyme is deficient in acute intermittent porphyria?
Uroporphyrinogen I synthetase
What enzyme is deficient in congenital erythropoietic porphyria?
Uroporphyrinogen III cosynthase
What disease has a genetic deficiency in adenosine deaminase?
SCID
In what idsease is there a deficiency in hypoanthine guanine phosphoribosyl transferase (HGPRT)
Lesch-Nyhan syndrome
What enzyme is deficient in selective T cell immunodeficiency?
purine nucleoside phosphorylase
What substrate builds up in Tay-Sachs disease?
Ganglioside GM2
What toxin ADP-ribosylates via Gs protein to inc cAMP?
cholera toxin
What vit derivatives are used for growth and differentiation of epithelium for reproductive and embryonic development?
Vit A
Light causes isomerization of what in the eyes?
11-cis-retinal to trans-retinal (activated rhodopsin)
What are the 2 actions of calcitonin?
- inc ca excretion from the kidney
2. inc bone mineralization
What causes an inc in bone mineralization and Ca2+, as well as PO4 absorption from teh GI tract and kidney tubules?
Vit D
What 2 factors cause PTH to be secreted?
- Dec in blood Ca2+
2. Dec in PO4 conc
What in the human genome differs in each indiv that can serve as an ID marker?
RFLP - restriction fragment length polymorphism
What test is used to ID HIV positive patients?
ELISA
What toxin ADP-ribosylates via Gi to inc cAMP
pertussis toxin
What vit is essential for normal Ca2+ and PO4 metabolism?
vit D
What vit is deficient in a person who has impaired taste, night blindness and inc ris for having an abortion?
Vit A
What bond does an endonuclease cleave?
3’, 5’ internal phosphodiesterase bond
What protein separates base pairs and unwinds DNA at the replication fork?
helicase (ATP-dependent)
What vit def cause liver necrosis and RBC fragility?
Vit E def
What direction is a new DNA strand made?
5’ to 3’
What enzyme has a 5’ to 3’ synthesis activity and 3’ exonuclease activity?
DNA polymerase III
what enzyme makes a ds cut through DNA, needs ATP, and introduces neg supercoiling?
topoisomerase II
What eukaryotic DNA polymerase is used for: DNA replication?
a- and delta polyerase
What eukaryotic DNA polymerase is used for: replication in mito?
gamma-polymerase
What eukaryotic DNA polymerase is used for: DNA repair?
b-polymerase
What is the orientation of the gene seq strand?
5’ to 3’ (same as RNA)
What is the location of the TATA box in prokaryotes?
10 bases downstream
What binds to the promotor region in procaryote?
Sigma factor
What enzymes has a 5’ to 3’ synthesis of the Okazaki fragments, 3’ exonuclease activity, and 5’ exonuclease activity?
DNA polymerase I
What position of the anticodon does the “wobble” hypothesis occur?
position 1 of the anticodon (the 5’ end) which is the same as position 3of the codon (the 3’ end)
3 stop codons?
UAA, UAG, UGA
What stops transcription in procaryotes?
Rho factor or a hairpin loop
3 post-transcriptional modifications?
- 7 methyl guanine cap on 5’ end
- polyA tail on 3’ end
- removal of introns
Mutation in which a diff codon is added –> dif aa?
missense mutation
Aa attached to the 3’ end of the tRNA in eukaryotes?
methionine
Enzyme that makes tRNA and the 5sRNA
RNA pol III
2 aa requiring vit C for hydroxylation?
proline, lysine
Mutation that has a stop codon in place of previous codon
nonsense mutation
aa attached to the 3’ end of the tRNA in procaryotes
f-methionine
Enzme that makes rRNA (barring the 5s subunit)
RNA pol I
Site of action of cycloheximide?
peptidyl transferase (60s)
What translation factor is blocked by erythromycin?
EF - G
Lack of what vit causes multiple carboxylase def?
biotin
Enzyme that makes hnRNA/mRNA?
RNA pol II
What enzyme is def in cystathioninuria?
Cystathionase
What enzyme is deficient in maple syrup urine disease?
branched chain keto acid dehydrogenase
What is the site of action of puromycin?
aminoacyl tRNA (A site)
What translational factor is blocked by both diphtheria and Pseudomonas toxins?
Elongtaion factor 2
What substrate gets built up in Gaucher’s disease?
Glucosyl cerebroside
What enzyme is deficient in homocystinuria?
homocysteine methyl transferase or cystathionine synthetase
What substrate is bult up in Niemann-Pick disease?
sphingomyelin
What is the second messenger system used by growth factors?
Tyrosine kinase
What is the name of the sequence on mRNA that precedes the start codon in prokaryotes?
Shine-Dalgarno seq
What aa undergoes N-glycosylation/
Aspargine
What translational factor is blocked by tetracycline?
EF-tu
What translational facotr is blocked by streptomycin?
IF-2
Which organisms have polycistronic mRNA
Prokaryotes (polycistronic and Prokaryotes both start with P)
In what disease are lysosomal enzymes released into the extracellular space where an accum of inclusion bodies compromises the cell’s function?
I-cell disease
Site of action of chloramphenicol?
peptidyl transferase (50s)
Is the hydroxyl (-OH) end of DNA and RNA at the 3’ or 5 end?
3’ (phsphate is at the 5’ end)
What tumor suppressor gene prevents a cell from enetering S phase when no growth factors are present?
Rb gene
Tumor suppressor gene that prevents a cell with damaged DNA from entering S phase
p53 gene
