Biochemistry- First Aid Flashcards
Amino Acids necessary for purine synthesis
Glycine, Aspartate, Glutamine
Drugs that interfere with de novo pyrimidine and purine synthesis
Leflunomide, Mycophenolate, ribavirin, hydroxyurea, 6-mercaptopurine, azathiopirine, 5-fluorouracil, methotrextate, trimethoprim, pyrimethamine
FA P. 67
Adenosine deaminase
Converts Adenosine–> Inosine
Deficiency leads to decreased DNA synthesis and decreased lymphocyte count (cause of AR SCID)
Lesch-Nyhan syndrome (loss of HGPRT, x-linked)
HGPRT converts guanine–> GMP and hypoxanthine–> IMP
Results in excess uric acid production and de novo purine synthesis
Findings: intellectual disability, self-mutilation, aggression, hyperuricemia, gout, dystonia
RNA polymerase types in the eukaryote
I- makes rRNA
II- makes mRNA
III- makes tRNA
Note- 1 RNA polymerase makes all 3 kinds of RNA in prokaryotes
RNA processing in eukaryotes
Capping of the 5’ end with 7-methylguanosine cap
Polyadenylation of 3’ end
Splicing out of introns
Regulators of the cell cycle
Cyclin-CDK complexes Tumor supressors (p53 and hypophosphorylated Rb inhibit G1 to S progression)
Inclusion Cell Disease
Defect in phosphotransferase which phosphorylates mannose residues on glycoproteins destined for the lysosome
Findings: coarse facial features, clouded corneas, restricted joint movement, high plasma levels of lysosomal enzymes
Drugs that act on microtubules
Mebendazole (anti-helminthic), Griseofulvin (anti-fungal), Colchicine (anti-gout), Vincristine (anti-cancer), Paclitaxel (anti-cancer)
Collagen Types
I- most common, found in bone, skin, tendon, fascia, cornea, and late wound repair
II- cartilage, vitreous body, nucleus pulposus
III- reticulin, blood vessels
IV- basement membrane, basal lamina lens
Marfan syndrome (cause)
Defect in fibrillin (fibrillin-1), a glycoprotein scaffold for elastin
Emphysema (cause)
Loss of alpha-1-antitrypsin, an inhibitor of elastase activity
Trinucleotide repeat diseases
Fragile X- CGG
Friedreich ataxia- GAA
Huntington’s- GAG
Myotonic dystrophy- CTG
Findings of Down syndrome (trisomy 21)
ID, flat facies, prominent epicanthal folds, single palmar crease, gap between 1st 2 toes, duodenal atresia, Hirschsprung disease, congenital heart disease, ASD
Findings of Edwards syndrome (trisomy 18)
severe ID, rocker-bottom feat, micrognathia, low-set ears, clenched hands, prominent occiput, congenital heart disease
Findings of Patau syndrome (trisomy 13)
severe ID, rocker bottom feat, microphthalmia, microcephaly, cleft lip/palate, holoprosencephaly, polydactyly, congenital heart disease
Cri-du-chat syndrome
Congenital microdeletion of short arm of chromosome 5
Microcephaly, moderate to severe intellectual disability, high pitched crying, epicanthal folds, VSD
Williams syndrome
Congenital microdeletion of long arm of chromosome 7
Distinctive “elfin” facies, ID, hypercalcemia, well-developed verbal skills, extreme friendliness with strangers, cardiovascular problems
22q11 microdeletion
DiGeorge syndrome- thymic aplasia, parathyroid aplasia, cardiac defects
Velocardiofacial syndrome- cleft palate, abnormal facies, cardiac defects
TCA Cycle
citrate–> isocitrate–> alpha-ketoglutarate–> succinyl coA–> succinate–> fumarate–> malate–> oxaloacetate
Urea Cycle
ornithine + carbamoyl phosphate–> citrulline–> arginosuccinate–> arginine
Uses of NADPH (electron acceptor)
Steroid and fatty acid synthesis, respiratory burst, cytochrome P-450, glutathione reductase
Regulation of Pyruvate Dehydrogenase
ATP, Acetyl-CoA, NADH (-)
Citrate synthase
APT (-)
Isocitrate Dehydrogenase
ATP, NADH (-), ADP (+)
Alpha-KG dehydrogenase
Succinyl-CoA, NADH, ATP (-)
Electron transport inhibitors
Decrease proton gradient and block ATP synthesis
Ex. Rotenone, cyanide, antimycin A, CO
ATP synthase inhibitors
Directly inhibit mitochondrial ATP synthase, causing an increased proton gradient but not ATP snythesis
Ex. Oligomycin
Uncoupling agents
Increase permeability of membrane causing decreased proton gradient and increased consumption of O2, ATP synthesis stops but electron transport continues, generating heat
Ex. 2,4 Dinitrophenol, aspirin
Cause of essential fructosuria
defect in fructokinase
Cause of fructose intolerance
deficiency in aldolase B
Galactokinase deficiency
AR hereditary deficiency in galactokinase
Classic galactosemia
absence of galactose-1-phosphate uridyltransferase
Essential Amino Acids
Methionine, Valine, Histidine, Isoleucine, Phenylalanine, Threonine, Tryptophan, Leucine, Lysine
Phenylketonuria (AR deficiency in phenylalanine hydroxylase) findings
ID, growth retardation, seizures, fair ski, eczema, musty body odor
Alkaptonuria (cause)
congenital deficiency of homogentisate oxidase (homogentisic acid–> maleylacetoacetic acid, tyrosine–> fumarate)
Alkaptonuria (findings)
dark connective tissue, brown pigmented sclerae, urine turns black on prolonged exposure to air, arthralgias (homogentisic acid is toxic to cartilage)
Homocystinuria (findings)
increased homocysteine in urine, ID, osteoporosis, tall stature, kyposis, lens subluxation, thrombosis, atherosclerosis (stroke and MI)
Fabry disease (deficient enzyme, accumulated substrate, findings)
alpha-galactosidase A; ceramide trihexose; peripheral neuropathy of hands/feet, angiokeratomas, cardiovascular/renal disease
Gaucher disease (deficient enzyme, accumulated substrate, findings)
glucocerebrosidase; glucocerebroside; hepatosplenomegaly, pancytopenia, aspetic necorsis of femur, bone crises, Gaucher cells
Niemann-Pick disease (deficient enzyme, accumulated substrate, findings)
sphingomyelinase; sphingomyelin; progressive neurodegeneration, hepatosplenomegaly, cherry red spot on macula, foam cells
Tay-Sachs disease (deficient enzyme, accumulated substrate, findings)
hexosaminidase A; GM2 ganglioside; progressive neurodegeneration, developemental delay, cherry-red spot on macula, lysosomes with onion skin, no hepatosplenomegaly
Krabbe disease (deficient enzyme, accumulated substrate, findings)
Galactocerebrosidase; galactocerebroside; peripheral neuropathy, developemental delay, optic atrophy, globoid cells
Metachromatic leukodystrophy (deficient enzyme, accumulated substrate, findings)
arylsufatase A; cerebroside sulfate; central and peripheral demyelination with ataxia, dementia
Hurler syndrome
alpha-L-iduronidase; heparan sulfate; developemental delay, gargoylism, airway obstruction, corneal clouding, hepatosplenomegaly
Hunter syndrome
iduronate sulfatase; heparan sulfate; mild hurler with agressive behavior, no corneal clouding
Pyocyanin
Produced by P. aeruginosa, functions to generate ROS to kill competing microbes
Lactoferrin
protein found in secretory fluids and neutrophils that inhibits microbial growth via iron chelation
