NBME Final- Biochem + genetics 2024-2025. Questions & Correct Verified Answers. Graded A+, Exams of Biochemistry

Download NBME Final- Biochem + genetics 2024-2025. Questions & Correct Verified Answers. Graded A+ and more Exams Biochemistry in PDF only on Docsity! NBME Final- Biochem + genetics 2024- 2025. Questions & Correct Verified Answers. Graded A+ 22q11 deletion syndromes - ANSMicrodeletion at chromosome 22q11 variable presentations including Cleft palate, Abnormal facies, Thymic aplasia T-cell deficiency, Cardiac defects, and Hypocalcemia 2° to parathyroid aplasia. DiGeorge syndrome—thymic, parathyroid, and cardiac defects. Velocardiofacial syndrome—palate, facial, and cardiac defects. CATCH-22. Due to aberrant development of 3rd and 4th branchial pouches. Achondroplasia - ANSMutation of fibroblast growth factor receptor 3 (FGFR3) inhibits chondrocyte proliferation. Most common cause of dwarfism; limb length affected more than head or torso size. Full penetrance. Actonimyces - ANSanaerobe; normal flora in oral, reproductive, and GI; Causes oral/facial abscesses that drain through sinus tracts, forms yellow "sulfur granules;" can also cause PID with IUDs; treat with penicillin Acute phase reactants - ANSFactors whose serum concentrations change significantly in response to inflammation; produced by the liver in both acute and chronic inflammatory states. Notably induced by IL-6; includes C reactive protein, ferriting, fibrinogen, hepcidin, serum amyloid A Adenosine deaminase deficiency - ANS*Excess ATP* - prevents DNA synthesis due to (-) feedback -> low lymphocytes Albinism - ANSAutosomal recessive Defective tryosine-3-monooxygenase Tyrosine not converted to melanin Alkaptonuria - ANSCongenital deficiency of homogentisate oxidase in the degradative pathway of tyrosine to fumarate > pigment-forming homogentisic acid accumulates in tissue. Autosomal recessive. Usually benign. Findings: bluish-black connective tissue and sclerae (ochronosis); urine turns black on prolonged exposure to air. May have debilitating arthralgias (homogentisic acid toxic to cartilage). Aminoacyl-tRNA syntheses - ANSBinds correct AA to 3' end of tRNA via peptide bond Responsible for AA accuracy Anaphylaxis complement - ANSC3a, C4a, C5a AngelMan Syndrome - ANSPaternal imprinting: gene from dad is normally silent and Maternal gene is deleted/mutated. Results in inappropriate laughter ("happy puppet"), seizures, ataxia, and severe intellectual disability. 5% of cases due to paternal uniparental disomy (two paternally imprinted genes are received; no maternal gene received). ATP synthase inhibitors - ANSDirectly inhibit mitochondrial ATP synthase, causing an increase proton gradient. No ATP is produced because electron transport stops. Oligomycin. Autosomal Dominant Diseases (that we have covered) - ANSAchondroplasia, familial (absence of vas deferens, spermatogenesis may be unaffected) and subfertility in women (amenorrhea, abnormally thick cervical mucus). Nasal polyps, clubbing of nails. Composition of collagen - ANStranslation of collagen α chains (preprocollagen)—usually Gly-X-Y (X and Y are proline or lysine). Glycine content best reflects collagen synthesis (collagen is 1⁄3 glycine). hydroxylation of specific proline and lysine residues. Requires vitamin C; deficiency > scurvy. Cori disease - ANSdeficient debranching enzyme (alpha-1,6-glucosidase); findings= similar to Von Gierke, but milder, normal blood lactate levels. Accumulation of limit dextrin-like structures in cytosol. Cre-Lox system (experimental technique) - ANSCan inducibly manipulate genes at specific developmental points (eg, to study a gene whose deletion causes embryonic death). Cri-du-chat - ANSdeletion of 5p retardation, speech delay, heart defect Cri-du-Chat Syndrome - ANSCongenital microdeletion of short arm of chromosome 5 (46,XX or XY, 5p−). Findings: microcephaly, moderate to severe intellectual disability, high- pitched crying/mewing, epicanthal folds, cardiac abnormalities (VSD). Cri du chat = cry of the cat. Cystic Fibrosis - ANSAutosomal recessive CFTR gene - 3 nucleotide deletion (lose Phe) Cl- channel defective - misfolded channel protein gets degraded and lose Cl- secretion Thick mucous in bronchi, GI Cystic Fibrosis - ANSAutosomal recessive; defect in CFTR gene on chromosome 7; commonly a deletion of Phe508. Most common lethal genetic disease in Caucasian population. CFTR encodes an ATP- gated Cl− channel that secretes Cl− in lungs and GI tract, and reabsorbs Cl− in sweat glands. Most common mutation > misfolded protein > protein retained in RER and not transported to cell membrane, causing decreased Cl− (and H2O) secretion; increased intracellular Cl− results in compensatory increase in Na+ reabsorption via epithelial Na+ channels > increased H2O reabsorption > abnormally thick mucus secreted into lungs and GI tract. Increased Na+ reabsorption also causes more negative transepithelial potential difference. Cytokines secreted by all T cells - ANSIL2 and IL3 Cytokines secreted by macrophages - ANSIL1, IL6, IL8, IL12, TNF alpha Cytokines secreted by Th2 cells - ANSIL4, IL5, IL10 Cytosine Deamination - ANSTurns C -> U De novo nucleotide synthesis - ANS*Aspartate + glutamine* -> ribonucleotide -> deoxyribonucleotide *Methoxtrexate* - inhibit dihydrofolate reductase Di George syndrome - ANSmicrodeletion/duplication cleft palate, retardation, T-cell deficiency DNA Methylation - ANS*Distinguish* - mismatch repair enzymes distinguish between old + new DNA *CpG islands* - methylation makes it mute Down Syndrome (trisomy 21) - ANSFindings: intellectual disability, flat facies, prominent epicanthal folds, single palmar crease, gap between 1st 2 toes, duodenal atresia, Hirschsprung disease, congenital heart disease (eg, atrioventricular septal defect), Brushfield spots. Associated with early-onset Alzheimer disease (chromosome 21 codes for amyloid precursor protein) and ^ risk of ALL and AML. 95% of cases due to meiotic nondisjunction (^ with advanced maternal age; from 1:1500 in women < 20 to 1:25 in women > 45 years old). 4% of cases due to unbalanced Robertsonian translocation, most typically between chromosomes 14 and 21. 1% of cases due to mosaicism (no maternal association; postfertilization mitotic error). Incidence 1:700. Drinking age (21). Most common viable chromosomal disorder and most common cause of genetic intellectual disability. Duchenne Muscular Dystrophy - ANSX-linked disorder typically due to frameshift or nonsense mutations > truncated dystrophin protein > inhibited muscle regeneration. Weakness begins in pelvic girdle muscles and progresses superiorly. Pseudohypertrophy of calf muscles due to fibrofatty replacement of muscle A . Gower maneuver—patients use upper extremities to help them stand up. Waddling gait. Onset before 5 years of age. Dilated cardiomyopathy is common cause of death. Duchenne = deleted dystrophin ^ CK and aldolase are seen; Western blot and muscle (antimycin) A: complex 3 inhibitor. CO/CN: complex 4 inhibitors (4 letters). ELISA - ANS*Blood test* - to see if antigens or antibodies are present in the blood - use of color enzyme Encapsulated bacteria (that we have covered) - ANSStreptococcus pneumoniae, Escherichia coli, group B Strep Encapsulated bacteria vaccines - ANSPrevnar (PCV, pneumococcal conjugate vaccine), H influenzae B, meningococcal vaccine (conjugate vaccine) Endotoxin - ANSLipid A component of LPS (structural component, released when lysed); outer cell membrane of most G- bacteria; can lead to fever, shock (hypotension); induces TNF, IL1, and IL6 Enterococci - ANSGram cocci. Enterococci (E faecalis and E⊕ faecium) are normal colonic flora that are penicillin G resistant and cause UTI, biliary tract infections, and subacute endocarditis (following GI/GU procedures). Catalase , PYR , variable hemolysis. VRE ⊝ ⊕ (vancomycin-resistant enterococci) are an important cause of nosocomial infection. Essential Fructosuria - ANSInvolves a defect in fructokinase. Autosomal recessive. A benign, asymptomatic condition, since fructose is not trapped in cells. Symptoms: fructose appears in blood and urine Euk RNA polymerases - ANSRNA pol 1 - rRNA RNA pol 2 - mRNA RNA pol 3 - tRNA *Inhibitors* - Actinomycin D Familial adenomatous polyposis (FAP) - ANSColon becomes covered with adenomatous polyps after puberty. Progresses to colon cancer unless colon is resected. Mutations on chromosome 5q (APC gene); 5 letters in "polyp." Familial adenomatous polyposis cancer (APC) - ANSAutosomal dominant Colon covered w/ adenomatouss polyps. Colon cancer - 100% over 50 years old Flow Cytometry uses - ANS-Laboratory technique to assess size, granularity, and protein expression (immunophenotype) of individual cells in a sample. -Commonly used in workup of hematologic abnormalities (eg, paroxysmal nocturnal hemoglobinuria, fetal RBCs in mother's blood) and immunodeficiencies (eg, CD4 cell count in HIV). Fluorescence in situ hybridization (FISH) - ANSFluorescent DNA or RNA probe binds to specific gene site of interest on chromosomes. Used for specific localization of genes and direct visualization of chromosomal anomalies at the molecular level. -Microdeletion—no fluorescence on a chromosome compared to fluorescence at the same locus on the second copy of that chromosome - Translocation—fluorescence outside the original chromosome -Duplication—extra site of fluorescence on one chromosome relative to its homologous chromosome Fluorescence in- situ hybridization - ANSFluorescent DNA used to detect micro deletions and anomalies Fragile X syndrome - ANSAutosomal recessive *Mutation* - buildup of CCG repeats cause methylation -> inactivation *Male affected* - some may not show signs if not enough CCG mental handicap Fragile X Syndrome - ANSX-linked dominant inheritance. Trinucleotide repeat in FMR1 gene > methylation > decreased expression. The 2nd most common cause of genetic intellectual disability (after Down syndrome). Findings: post-pubertal macroorchidism (enlarged testes), long face with a large jaw, large everted ears, autism, mitral valve prolapse. Trinucleotide repeat disorder (CGG)n. Fragile X = eXtra large testes, jaw, ears Frameshift Mutation - ANS*Deletion or insertion of nucleotide* - misread frame downstream Duchenne muscular dystrophy Galactokinase deficiency - ANSHereditary deficiency of galactokinase. Galactitol accumulates if galactose is present in diet. Relatively mild condition. Autosomal recessive. Symptoms develop when infant begins feeding (lactose present in breast milk and routine formula). Symptoms: galactose appears in blood (galactosemia) and urine (galactosuria); infantile cataracts. May present as failure to track objects or to develop a social smile. Gaucher disease - ANSlysosomal storage disease;deficient Glucocerebrosidase (β-glucosidase) enzyme; Most common. Hepatosplenomegaly, pancytopenia, osteoporosis, aseptic necrosis of femur, bone crises, Gaucher cells (lipid-laden macrophages resembling crumpled tissue paper). Glucokinase - (tests for glucose only); reducing sugar can be detected in the urine (nonspecific test for inborn errors of carbohydrate metabolism). Symptoms: hypoglycemia, jaundice, cirrhosis, vomiting. Hereditary nonpolyposis colorectal cancer (HNPCC) - ANSdefective mismatch repair Heterogeneity - ANSMulti mutations cause same phenotype Hexokinase - ANSfound in most tissues; low Km (high affinity) and low Vmax (low capacity); feedback inhibited by G6P Homocysteinuria - ANSAll forms result in excess homocysteine. Findings: increased homocysteine in urine, intellectual disability, osteoporosis, marfanoid habitus, kyphosis, lens subluxation (downward and inward), thrombosis, and atherosclerosis (stroke and MI) Homocystinuria - ANSAutosomal recessive Defective cystathione B-synthase Met not metabolized, B12 low - skeletal issues Huntington's disease - ANSAutosomal dominant Chromosome 4 - trinucleotide repeat (CAG) dementia, depression I-cell disease - ANSLysosome hydrolases aren't transported from Golgi properly -> go into serum *Result* - clouded cornea, bad joints, fatal in children IgE - ANSBinds mast cells and basophils; cross-links when exposed to allergen, mediating immediate (type I) hypersensitivity through release of inflammatory mediators such as histamine. Mediates immunity to worms by activating eosinophils. Lowest concentration in serum. IL1 - ANSaka osteoclast-activating factor. Causes fever, acute inflammation. Activates endothelium to express adhesion molecules. Induces chemokine secretion to recruit WBCs IL10 - ANSAttenuates inflammatory response. Decreases expression of MHC class II and Th1 cytokines. Inhibits activated macrophages and dendritic cells. Also secreted by regulatory T cells. TGF-beta and IL10 both attenuate the immune response. IL12 - ANSInduces differentiationof T cells into Th1 cells. Activates NK cells. IL2 - ANSStimulates growth of helper, Cytotoxic, and regulatory T cells IL3 - ANSSupports growth and differentiation of bone marrow stem cells IL4 - ANSInduces differentiation of T cells into Th2 cells. Promotes growth of B cells. Enhances class switching to IgE and IgG. IL5 - ANSPromotes growth and differentiation of B cells. Enhances class switching to IgA. Stimulates growth and differentiation of eiosinophils. IL6 - ANSCauses fever and stimulates production of acute phase proteins IL8 - ANSMajor chemotactic factor for neutrophils. "Clean up on aisle 8" > neutrophils are recruited by IL8 to clear infections. Imprinting - ANS*Maternal imprinting* - mom gene is silent -Prader-Willi syndrome - mutant dad gene *Paternal imprinting* - dad gene is silent - Angelman syndrome - mutant mom gene Imprinting - ANSAt some loci, only one allele is active; the other is inactive (imprinted/inactivated by methylation). With one allele inactivated, deletion of the active allele > disease. Both Prader-Willi and Angelman syndromes are due to mutation or deletion of genes on chromosome 15. Inhibitors of opsonization (prevents self opsonizing) - ANSDecay accelerating factor (DAF, aka CD55) and C1 esterase Interferon alpha and beta - ANSA part of innate host defense against both RNA and DNA viruses. Interferons are glycoproteins synthesized by virus-infected cells that act locally on uninfected cells, "priming them" for viral defense by helping to selectively degrade viral nucleic acid and protein. Interferon gamma (IFN gamma) - ANSsecreted by NK cells and Th1 cells in response to IL12 from macrophages; stimulates macrophages to kill phagocytosed pathogens. Inhibits differentiation of Th2 cells. Also activates NK cells to kill virus infected cells. Increases MHC expression and Ag presentation by all cells. Intermediate filaments - ANSvimentin, desmin, cytokeratin, lamins Irreversible enzymes in gluconeogenesis - ANS"Pathway Produces Fresh Glucose" > Pyruvate carboxylase, Phosphoenolpyruvate carboxykinase, Fructose-1,6-bisphosphatase, Glucose-6-phosphatase Killed virus vaccines - ANSRabies, Influenza (injected), Salk Polio, and HAV vaccines. Killed/inactivated vaccines induce only humoral immunity but are stable. SalK = Killed. RIP Always. Klinefelter syndrome - ANSExtra X Lac Operon - ANSC3b and IgG Maple syrup urine disease - ANSBlocked degradation of branched amino acids (Isoleucine, Leucine, Valine) due to decreased branched-chain α-ketoacid dehydrogenase (B1). Causes increase in α- ketoacids in the blood, especially those of leucine. Causes severe CNS defects, intellectual disability, and death. Treatment: restriction of isoleucine, leucine, valine in diet, and thiamine supplementation. Autosomal recessive. "I Love Vermont maple syrup from maple trees (with B1ranches)." Maple Syrup Urine disease - ANSBlocked degradation of valine, leucine, isoleucine (branched AA) *Defective* - alpha- keotoacid dehydrogenase *Result* - CNS defects, death, disability Marfan syndrome - ANSAutosomal dominant Defective fibrin (elastin) -> CT disorder w/ skeleton, hear, eyes Marfan Syndrome - ANScaused by a defect in fibrillin, a glycoprotein that forms a sheath around elastin. Marfan syndrome genetic factors - ANSFBN1 gene mutation on chromosome 15 > defective fibrillin (scaffold for elastin) > connective tissue disorder affecting skeleton, heart, and eyes. Findings: tall with long extremities, pectus excavatum, hypermobile joints, and long, tapering fingers and toes (arachnodactyly); cystic medial necrosis of aorta > aortic incompetence and dissecting aortic aneurysms; floppy mitral valve. Subluxation of lenses, typically upward and temporally. McArdle disease - ANSdeficient skeletal muscle glycogen phorphorylase; increased glycogen in muscle, but muscle cannot break it down > painful Muscle cramps, Myoglobinuria (red urine) with strenuous exercise, and arrhythmia from electrolyte abnormalities. Michaelis-Mentin equation - ANS[S] = [ES]/[Efree] Km = [S] at (1/2)Vmax Microarray - ANSDetects SNP's that are relevant to genetic disorders Microfilaments - ANSactin, myosin Microtubules - ANScilia, flagella, centrioles, mitotic spindle *Dynein* - retrograde to microtubule (back to centromere) *Kinesin* - anterograde to microtubule (away from centromere) Mismatch repair - ANS*MutS protein* - recognizes DNA strand bubble (mismatch) *MutL* - binds to mutS and threads DNA from knick back to mismatch -> degrades it Deletion replaces + sealed Mismatch repair - ANSNewly synthesized strand is recognized, mismatched nucleotides are removed, and the gap is filled and resealed. Occurs predominantly in G2 phase of cell cycle. Defective in Lynch syndrome (hereditary nonpolyposis colorectal cancer [HNPCC]). Missense Mutation - ANSNucleotide change -> AA change *Sickle cell disease* - glutamic acid to valine Mitosis Phases - ANS*Prophase* - chromatin condense, nucleus begins to disappear *Prometaphase* - kinetochores develop on centromere, nuclear envelope gone *Metaphase* - condensed chromosomes align in center, attached to spindles *Anaphase* - spindles pull apart chromatids via spindle lengthening *Telophase* - cytokinesis (midbody clips it off) + nucleus reforms Mnemonic for Blotting Procedures - ANSSNoW DRoP: Southern = DNA Northern = RNA Western = Protein Mnemonic for cytokines that attenuate the immune response - ANSTGF beta dn IL10 both AtTENuate the immune response Mnemonic for effects of endotoxins - ANSENDOTOXINS: Edema Nitric oxide DIC/Death Outer membrane TNF-α O-antigen + core polysaccharide + lipid A eXtremely heat stable IL-1 and IL-6 Neutrophil chemotaxis Shock Mosaicism - ANSPresence of genetically distinct cell lines in the same individual. Somatic mosaicism—mutation arises from mitotic errors after fertilization and propagates through multiple tissues or organs. Gonadal mosaicism—mutation only in egg or sperm cells. Myotonic Type 1 Dystrophy - ANSAutosomal dominant. CTG trinucleotide repeat expansion in the DMPK gene > abnormal expression of myotonin protein kinase > myotonia, muscle wasting, cataracts, testicular atrophy, frontal balding, arrhythmia. My Tonia, My Testicles (testicular atrophy), My Toupee (frontal balding), My Ticker (arrhythmia). Neurofibromatosis Type 1 - ANSAutosomal dominant 100% penetrance neurofibromas, Lisch nodules, cafe du lait spots Neurofibromatosis type 1 (aka von odor. Treatment: Decrease phenylalanine and increase tyrosine in diet, tetrahydrobiopterin supplementation. Autosomal recessive. PKU patients must avoid aspartame (artifical sweetener) Pleiotropy - ANSOne gene -> multiple phenotype effects Prader-Willi Syndrome - ANSMaternal imprinting: gene from mom is normally silent and Paternal gene is deleted/mutated. Results in hyperphagia, obesity, intellectual disability, hypogonadism, and hypotonia. 25% of cases due to maternal uniparental disomy (two maternally imprinted genes are received; no paternal gene received). Pre-mRNA Splicing - ANS1. snRNPs' combines + form splicosome then attach to transcript. 2. Lariat-shaped intermediate made 3. Lariat is cut off to remove intron + join 3 exons Primary ciliary dyskinesia - ANSCilia immotive due to dynein defects. *Results* - respiratory issues, infertility (bad sperm) + fallopian cilia Prok RNA polymerase - ANSRNA polymerase - all RNAs *Inhibitors* - Actinomycin D, Rifampin Protein A - ANSbacterial virulence factor secreted by S aureus; binds Fc region of IgG; prevents opsonization and phagocytosis protein alpha-helix - ANS*Hydrogen bond* - holds structure together *Bases* - facing outward *Proline* - disrupts the helix Protein synthesis - ANS*Initation* - GTP hydrolysis with initiation factors - assembly ribosome w/ mRNA *Elongation* - aminoacyl-tRNA goes to A site and peptide transferase is responsible for growing peptide *Termination* - RF goes to A site and triggers stop Pyruvate carboxylase - ANSenzyme catalyzes first step in gluconeogenesis (pyruvate > oxaloacetate); REQUIRES BIOTIN & ATP Pyruvate dehydrogenase complex - ANSMitochondrial enzyme complex linking glycolysis and TCA cycle. Differentially regulated in fed/fasting states (active in fed state). Reaction: pyruvate + NAD+ + CoA acetyl- CoA + CO2 + NADH. The complex contains 3 enzymes that require 5 cofactors: 1. Thiamine pyrophosphate (B1) 2. Lipoic acid 3. CoA (B5, pantothenic acid) 4. FAD (B2, riboflavin) 5. NAD (B3, niacin) Activated by: ^ NAD+/NADH ratio ^ ADP ^ Ca2+ Pyruvate dehydrogenase complex deficiency - ANSCauses a buildup of pyruvate that gets shunted to lactate (via LDH) and alanine (via ALT). X-linked. Presents as: Neurologic defects, lactic acidosis, increased serum alanine starting in infancy. Treated with: ketogenic diet (increase Lys and Leu in diet) Rate limiting enzyme in gluconeogenesis - ANSfructose-1,6-bisphosphatase; inhibited by AMP & F2,6BP Rate limiting enzyme in glycolysis - ANSphosphofructokinase 1 (PFK1); activated by AMP & F2,6BP, inhibited by ATP & citrate Rate limiting enzyme of de novo purine synthesis - ANSglutamine- phosphoribosylpyrophosphate (PRPP) amidotransferase; inhibited by AMP, inosine monophosphate (IMP), & GMP Rate limiting enzyme of glycogenesis - ANSglycogen synthase; activated by G6P, insulin, & AMP; inhibited by epinephrine & glucagon Rate limiting enzyme of glycogenolysis - ANSGlycogen phosphorylase; activated by epinephrine, glucagon, & AMP; inhibited by G6P, insulin, & ATP Rate limiting enzyme of HMP shunt (pentose phosphate pathway) - ANSglucose-6-phosphate dehydrogenase (G6PD); activated by NADP, inhibited by NADPH Rate limiting enzyme of TCA cycle - ANSIsocitrate dehydrogenase; activated by ADP, inhibited by ATP & NADH Rate limiting step of de novo pyrimidine synthesis - ANScarbamoyl phosphate synthetase II; activated by ATP & PRPP, inhibited by UTP Regulation by fructose-2,6- bisphosphate - ANSFBPase-2 (fructose bisphosphatase-2) and PFK-2 (phosphofructokinase-2) are the same bifunctional enzyme whose function is reversed by phosphorylation by protein kinase A. Fasting state: increased glucagon > increased cAMP > increased protein kinase A > increased FBPase-2, decreased PFK-2, less glycolysis, more gluconeogenesis. Fed state: increased insulin > decreased cAMP > decreased protein kinase A > decreased FBPase-2, increased PFK-2, more glycolysis, less gluconeogenesis. Regulatory T cells - ANSHelp maintain specific immune tolerance by suppressing CD4 and CD8 T-cell effector (Group A strep) - ANSGram cocci. Group A strep cause: - Pyogenic—⊕ pharyngitis, cellulitis, impetigo, erysipelas - Toxigenic—scarlet fever, toxic shock-like syndrome, necrotizing fasciitis - Immunologic— rheumatic fever, glomerulonephritis Bacitracin sensitive, β-hemolytic, pyrrolidonyl arylamidase (PYR) . Antibodies to M protein enhance host ⊕ defenses against S pyogenes but can give rise to rheumatic fever. ASO titer detects recent S pyogenes infection. J NES (major criteria for acute♥ rheumatic fever): Joints—polyarthritis —carditis Nodules ♥ (subcutaneous) Erythema marginatum Sydenham chorea Pharyngitis can result in rheumatic "phever" and glomerulonephritis. Impetigo usually precedes glomerulonephritis. Scarlet fever—blanching, sandpaper-like body rash, strawberry tongue, and circumoral pallor in the setting of group A streptococcal pharyngitis (erythrogenic toxin ). T cell rule of 8 ⊕ mnemonic - ANSMHC II × CD4 = 8; MHC I × CD8 = 8. Tay-Sachs disease - ANSlysosomal storage disease; deficient hexosaminidase A; Progressive neurodegeneration, developmental delay, "cherry-red" spot on macula, lysosomes with onion skin, no hepatosplenomegaly (vs Niemann-Pick). Th1 cells - ANSsecretes IFN-γ; activates macrophages and CTLs; differentiation induced by IFN-γ and IL12; inhibited by IL4 and IL10 Th2 cells - ANSSecretes IL4, IL5, IL10, IL13; recruits eiosinophils for parasite defense and promotes IgE production; differentiation induced by IL4; inhibited by IFN-γ TNF alpha - ANSMediates septic shock. Activates endothelium. Causes WBC recruitment, vascular leak. Trisomies - ANS*13* - dies after birth (Patau syndrome) *18* - dies after birth (Edward's syndrome) *21* - lives (Down's syndrome) tRNA structure - ANS*D-arm* - recognizes aminoacyl-tRNA syntheses *Anti-codon loop* - it's anti-codon binds to codon *T-arm* - binds to ribosome Tumor Suppressors - ANSp53 + Rb - inhibit S phase @ restriction point Turners syndrome - ANSMissing X Type I Collagen - ANSMost common (90%)— Bone (made by osteoblasts), Skin, Tendon, dentin, fascia, cornea, late wound repair. Type I: bone. decreased production in osteogenesis imperfecta type I. Type II Collagen - ANSCartilage (including hyaline), vitreous body, nucleus pulposus. Type II: cartwolage. Type III Collagen - ANSReticulin—skin, blood vessels, uterus, fetal tissue, granulation tissue. Type III: deficient in the uncommon, vascular type of Ehlers-Danlos syndrome (ThreE D). Type IV Collagen - ANSBasement membrane, basal lamina, lens. Type IV: under the floor (basement membrane). Defective in Alport syndrome; targeted by autoantibodies in Goodpasture syndrome. Uncoupling agents - ANSincrease permeability of membrane, causing a decrease in proton gradient and increase in O2 consumption. ATP synthesis stops, but electron transport continues. Produces heat. 2,4-Dinitrophenol (used illicitly for weight loss), aspirin (fevers often occur after aspirin overdose), thermogenin in brown fat. Uniparental Disomy - ANSOffspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent. Heterodisomy (heterozygous) indicates a meiosis I error. Isodisomy (homozygous) indicates a meiosis II error or postzygotic chromosomal duplication of one of a pair of chromosomes, and loss of the other of the original pair. Vibrio cholorae - ANSGram , flagellated, comma shaped, oxidase , grows in alkaline ⊝ ⊕ media. Endemic to developing countries. Produces profuse rice-water diarrhea via enterotoxin that permanently activates Gs, cAMP. Sensitive to stomach acid (acid labile); requires large inoculum (high ID50) unless host has decreased gastric acidity. Prompt oral rehydration is necessary. Viral subunit vaccines - ANSHBV (antigen = HBsAg), HPV (types 6, 11, 16, and 18). Von Gierke disease - ANSdeficient Glucose-6-phosphatase; findings= Severe fasting hypoglycemia, ^^ Glycogen in liver, ^ blood lactate, ^ triglycerides, ^ uric acid (Gout), and hepatomegaly. von Hippel- Lindau disease - ANSDisorder characterized by development of numerous tumors, both benign and malignant. Associated with deletion of VHL gene (tumor suppressor) on chromosome 3 (3p). Von Hippel-