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Biochem Flashcards

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1
Q

Orotic aciduria

A

Inability to convert orotic acid –> UMP (pyrimidine synthesis)

Sx: Inc orotic acid in urine
megaloblastic anemia (does NOT improve w/ B12)
NO hyperammonemia (vs. OTC)
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2
Q

Adenosine deaminase deficiency

A

AR

Accumulation of adenosine, ATP, dATP
dATP inhibits Ribonucleotide reductase –> inhibits DNA synthesis –> dysfxn T & B-cells

SCID

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3
Q

SELF-MUTILATION
Gout
Choreoathetosis
Retardation

A

Lesch-Nyan syndrome

  • HGPRT deficiency
  • Guanine & hypoxanthine can’t –> GMP & IMP = Gets degraded to uric acid –> hyperuricemia
  • Excess IMP & GMP –> excess purines –> CNS damage
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4
Q

Nucleotide excision repair defect

A

Xeroderm pigmentosum

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5
Q

Mutation of DNA mismatch repair

A

Hereditary Nonpolyposis Colorectal Cancer (HNPCC)

  • AD
  • recognizes UNmethylated new strand mismatches
  • 80% –> CRC
  • PROXIMAL colon alway involved
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6
Q

Cerebellar (ataxia)
Spider angiomas
IgA deficiency

A

Ataxia telangiectasia

- ATM gene - DNA repair enzymes

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7
Q

alpha-amantin

A

Inhibits RNA Pol II (mRNA)

Found in death cap mushrooms –> liver failure

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8
Q

Aminoglycosides

A

Bind 30S

Inhibits formation of initiation –> misread mRNA

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9
Q

Chloramphenicol

A

Inhibits 50S peptidyl transferase

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10
Q

Macrolides

A

Binds 50S –> Blocks translocation

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11
Q

Clindamycin & Chloramphenicol block?

A

Peptide bond formation

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12
Q

Tetracyclines

A

Bind 30S

Prevent aminoacyl-tRNA synthetase attachment

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13
Q

I-Cell Disease

A

Inherited lysosomal storage disorder

Failure to + Mannose-6-Phosphate –> secrete enzymes vs. –> lysosome

Sx:
Coarse facial features
Clouded corneas
Restricted joints

Fatal in childhood

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14
Q

Pyogenic infections - staph, strep
Albinism
Peripheral neuropathy

A

Chediak-Higashi Syndrome

  • Failure of phagosome & lysosome fusion
  • Defect Lysosomal Regulator Trafficking gene (LYST) = microtubule polymerization
  • AR
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15
Q

Kartagener’s Syndrome

A

Dynein arm defect (retro –> -)
Immoble cilia

Infertility
Bronchiectasis
Recurrent sinusitis
Assoc w/ situs inversus

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16
Q

Oubain

A

Inhibits binding to K+ site –> inhibits Na/K pump

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17
Q

Cardiac glycoside MOA

A

Inhibit Na/K pump –> inhibits Na/Ca exchange –> Inc Ca –> Inc contractility

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18
Q

Scurvy

A

Lack of Vit C

Required for hydroxylation of collagen w/ proline or lysine

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19
Q

Type I collagen defect

A

Osteogenesis imperfecta
Type I = AD
Type II = Fatal

Type I collagen (glycosylation)

  1. Multiple fx
  2. Blue sclera
  3. Hearing loss
  4. Dental imperfections
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20
Q

Type III Collagen defect

A

Ehlers-Danlos
Type III collagen defect (cross-linking)

  1. Hyperextensible joints
  2. Easy bruising
  3. Berry anyuerysms
  4. Hyper mobile joints/dislocation
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21
Q

Basket-weave GBM, Type IV collagen defect

A

Alport syndrome

  1. Deafness
  2. Nephritis
  3. Ocular disturbances
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22
Q

Defect in Fibrillin

A

Marfan’s Syndrome

  • Tall w/ long extremities
  • Pectus excavatum
  • Long, tapering fingers & toes (Arachnodactyly)
  • Medial necrosis of aorta –> dissecting AAs & aortic insufficiency
  • Floppy mitral valve
  • Subluxation of lens

Locus heterogeneity w/ MEN 2B, homocystinuria

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23
Q

alpha-1 anti-trypsin deficiency

A

Misfolded protein aggregates in heptocyte ER –> cirrhosis
PAS + globules in liver

Dec elastic tissu in lungs –> PANACINAR emphysema

Codominant trait

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24
Q

Southern Blot

A

DNA

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25
Southwestern Blot
DNA-binding proteins (transcription factors)
26
Microarray
Level of gene expression
27
ELISA
Ag-Ab reactivity
28
FISH
Localization of genes & visualize anomalies Fluorescence = gene present
29
Incomplete penetrance
Not everyone w/ mutation shows sx
30
Pleiotropy
1 gene >1 effect PKU
31
Loss of heterogeneity
Mutation in tumor suppressor gene - complimentary allele must be deleted --> cancer
32
Mosaicism
Cells in body differ d/t POST-fertilization loss of genetic material germ-line --> disease not in parent's cells
33
Hyperphagia, hypogonadism, hypotonia, Paternal deletion
Prader-Willi - should be active Maternal in inactivated
34
Seizures, ataxia, inappropriate laughter "happy puppet," maternal deletion
Angleman Syndrome - should be active Paternal inactive
35
AR trait
1 generation | 2-carrier parents
36
XR trait
No male-to-male More severe in males Sons of heterozygous mothers = 50%
37
XD trait
ALL females of affected father | Both MF affected
38
FGFR3 mutation
Achondroplasia - enchondral ossification Dwarfism Short limbs NORMAL trunk & head Normal lifespan & fertility Assoc w/ advanced paternal age AD & sporadic
39
AD Polycystic Kidney Disease
Adults BILATERAL MASSIVE kidneys PKD1 - Chr16 Polycystic liver Berry aneurysm MVP
40
AR Polycystic Kidney Disease
Infantile Congenital hepatic fibrosis & Liver cysts Portal HTN HTN
41
Familial Adenomatous Polyposis
APC gene - chr5 (5 letters in polyp) Polyps after puberty --> cancer
42
Familial hypercholesterolinemia
Defect/absent LDL receptor --> inc LDL Achilles tendon xanthomas Severe atherosclerosis -->MI b4 20
43
Osler-Weber-Rendu (Herediatry telangiectasia)
Telangiectasias Recurrent epistaxis Skin discolorations AVMs
44
Hereditary spherocytosis
Spectrin or Ankyrin defect Inc MCHC Cure = splenectomy
45
Huntington
CAG expansion Chr4 (hunting 4 food) caudate atrophy --> dec GABA & Ach Choreiform movements, progressive dementia
46
Multiple endocrine neoplasias (MEN) gene mutation
MEN 2A/B - RET gene
47
Lisch-nodules Cafe-au-lait Neural tumors Scoliosis
Neurofibromatosis Type I
48
B/L Acoustic schwannoma | Juvenile cataracts
Neurofibromatosis Type II NF2 gene - chr22 2 ears - NF2 - Chr22
49
Facial acne, hypopigmented lesion mainly on trunk, Hammartomas, Renal angiomyolipomas, Cardiac rhabdomyomas
Tuberous sclerosis - adenoma sebaceum - "ash leaf" spots - Inc astrocytomas
50
B/L renal cell carcinomas | Hemangioblastomas of retina, cerebellum, medulla
Von Hippel-Lindau Disease | - VHL gene on Chr3p
51
Recurrent pulmonary infections w/ PA & SA, Pancreatic insufficiency --> malabs of fat soluble vitamins, steatorrhea, FTT
AR CFTR gene Chronic bronchitis Bronchiectasis Infertility Inc Cl- sweat test Tx = *NAC* to loosen mucus plugs
52
Pelvic girdle --> superiorly Hypertrophy of calves Gower's maneuver
Duchenne's Muscular dystrophy - Frame-shift --> Deleted Dystrophin gene (DMD) --> muscle breakdown - longest gene in body = high mutation rate Dx: inc CPK & biopsy
53
MACRO-orchidism, long face, large jaw, MR
Fragile-X syndrome - FMR1 gene methylation & expression - CGG repeat 2nd most common cause of MR (Down) Fragile-X - Xtra large testes
54
Down syndrome
Trisomy 21 ``` Flat facies Prominent epicathal folds Simian crease Duodenal atresia ASD Inc ALL & Alzheimer ``` Inc beta-hCG US = Inc nuchal translucency
55
Trisomy 18
Edward's syndrome (Election age 18) Rocker-bottom feet Micrognathia Clenched hands Death w/in 1yr DEC beta-hCG
56
Trisomy 13
Patau syndrome (Puberty 13) ``` Rocker-bottom feet MicroOPHTHALMIA Cleft liP/Palate HoloProsencephaly Polydactyly ``` NORMAL enzyme levels
57
Robertsonian
Chr 13, 14, 15, 21, 22 2 acrocentric long arms fuse 2 short arms lost
58
Cri-du-chat
Deletion of short arm of chr5 (46, XX or XY, 5p-) High pitched cry/mew Epicanthal folds VSD Microcephaly
59
Williams syndrome
Deletion of long chr7 "Elfin" facies HyperCa EXTREME FRIENDLINESS w/ strangers
60
Vitamin A (retinol)
Source: liver, leafy vegetables Deficiency: night blindness Excess: Teratogenic, alopecia, fatigue
61
Vitamin B1
Thiamine decarboxylation rxns --> ATP synthesis Wernicke-korsakoff Ber1-Ber1
62
Wernicke-Korsakoff
B1 (thiamine) deficiency Ophthalmoplegia + ataxia + confabulation Memory loss Dorsal medial nucleus of thalamus & mamillary body damage
63
Wet Beri-Beri
High output cardiac failure (dilated cardio myopathy), edema
64
Dry Beri-Beri
Polyneuritis, symmetrical muscle wasting
65
Vitamin B2
Riboflavin Cheilosis Corneal vascularization
66
Vitamin B3
Niacin NAD derived from B3 (B3 = 3ATP) From tryptophan & requires B6 3 D's of B3: 1. Diarrhea 2. Dermatitis 3. Dementia Tx hyperlipidemia --> FLUSHING
67
Vitamine B5
Pantothenate (5 = "pent") Component of CoA & FA synthesis Deficiency: dermatitis, enteritis, alopecia, adrenal insufficiency
68
Vitamin B6
Pyridoxine Impaired Hb synthesis + Fe excess --> Sideroblastic anemia Convulsions Hyper-irritability Peripheral neuropathy
69
Vitamin B12
Cobalamin Co-factor for homocysteine methytransferase Animal products + microorganisms Large reserve in liver Deficiency causes: 1. spure 2. D. latum 3. pernicious anemia 4. No terminal ileum (Crohn's) Dx etiology = Schilling test Sx: Macrocytic, megaloblastic anemia (MCV >100) Hypersegmented PMNs Subacute combined degeneration
70
Folic Acid
--> THF (co-factor w/ B12 in methyl transfer) DNA & RNA synthesis Foliage Small reserves Deficiency causes: 1. Phenytoin, sulfas, MTX ``` Sx Macrocytic, megaloblastic anemia (MCV >100) Hypersegmented PMNs Most common vitamin deficiency Alcoholism & pregnancy ```
71
Biotin deficiency
excess egg whites - AVIDIN binds biotin
72
Vitamin C
Ascorbic acid Oxidized Fe3 --> Fe2 = Iron abs Hydroxylation of proline & lysine --> collagen synthesis Deficiency causes: 1. Scurvy - collagen synthesis defect Sx: Swollen gums, bruising, hemarthrosis, anemia, poor wound healing Excess: N/V/D, iron toxicity, fatigue
73
Vitamin D
``` D2 = ergo = plants D3 = cholecalciferol = milk, sun 25-OH = storage 1,25-OH = active ``` Function = intestinal Ca+ & Phos abs, bone mineralization Deficiency: Rickets Osteomalacia INADEQUATE AMOUNT IN BREAST MILK Excess: Loss of appetite, stupor Seen in sarcoid
74
Vitamin E
Protects erythrocytes from ROS Deficiency: Hemolytic anemia Muscle weakness Post column, spinocerebellar demyelination
75
Vitamin K
synthesized by intestinal flora Required for clotting factor synthesis - II, VII, IX, X Deficiency: Inc PT & aPTT Normal bleeding time Neonates = sterile intestines = can't make NOT in breast milk = injection to prevent hemorrhage After prolonged antibiotics
76
Zinc
Essential for many enzymes Zinc fingers - transcription factor motif ``` Deficiency: Delayed wound healing Hypogonadism Ded adult hair Dysgeusia ANOSMIA ```
77
Fomepizole
Inhibits alcohol dehydrogenase (0-order kinetics) ***antidote for methanol or ethylene glycol OD***
78
Disulfram (antabuse)
Inhibits acetaldehyde dehydrogenase --> acedalhedhye accumulates = hangover
79
Kwashiorkor
Protein malnutrition Edema Fatty liver change d/t dec APO synthesis
80
Marasmus
ENERGY malnutrition Tissue & muscle wasting Loss of subq fat
81
Electron transport inhibitors
Rotenone CN- Antimycin A CO
82
ATPsynthase inhibitors
Oligomycin
83
Uncoupling agents
Inc membrane permeability --> dec H+ gradient Produces heat 2,4-DNP Aspirin
84
G6PD Deficiency
NADPH required to keep glutathione reduced Glutathione detoxifies ROA & peroxides Dec NADPH --> HEMOLYTIC ANEMIA Most common human enzyme deficiency XR Common among Blacks Inc malarial resistance * Heinz bodies* * Bite cells*
85
Essential fructosuria
Defect in fructokinase AR Benign, Asx condition Fructose appears in urine
86
Fructose Intolerance
AR deficiency of ALDOLASE B Fruc-1-P accumulates --> less phis --> inhibits glycogenolysis & gluconeogenesis ``` Sx: Hypoglycemia Jaundice Cirrhosis Vomiting ```
87
Galactokinase deficiency
AR deficiency in galactokinase Galactitol accumulates Sx: Galactose in urine *Infantile cataracts* Failure to tract objects or develop smile
88
Classic galactosemia
AR absence of Galactose-1-P Uridyltransferase ``` Sx: FTT Jaundice Hepatomegaly *Infantile cataracts* ``` Tx = exclude galactose & lactose
89
Lactase deficiency
Age or hereditary loss (Blacks & Asians) | Loss of brush border enzyme
90
Oxidizing agents for G6PD deficiency
Oxidizing agents: 1. Fava beans 2. Sulfonamides 3. Primaquine 4. Anti-TB
91
Sorbitol dehydrogenase deficiency
Glucose --> sorbitol (aldose reductase) Sorbitol --> Fructose (sorbitol dehydrogenase) Sorbitol accumulates - cataracts - retinopathy - peripheral neuropathy
92
Acidic A.A.
Asp Glu Negatively charged at body pH
93
Basic A.A.
Arg Lys His Arg & His = growth Arg & Lys = histones His = no charge at body pH
94
Rate-limiting step in Urea Cycle
NH4 --> Carbamoyl Phos Carbamoyl phosphate synthetase I
95
Cori cycle
Lactate produced from pyruvate in anaerobic conditions instead of ATP Transported to liver to undergo gluconeogenesis back to glucose
96
Hyperammonemia
Excess NH4+ --> depletes alpha-KG --> inhibits TCA Tx: Limit protein Lactulose acidifies GI & traps NH4+ for excretion
97
Ammonia intoxication
``` tremor slurring somnolence vomiting cerebral edema blurred vision ```
98
OTC deficiency
XR Can't eliminate ammonia (urea cycle) Excess carbamoyl phos --> orotic acid
99
``` *Musty odor* MR Growth retardation Seizures Fair skin Eczema ```
PKU - AR Dec Phenylalanine hydroxylase - Tyrosine become essential - Excess phenylketones in urine
100
Dark CT Brown sclera *Urine turns black on exposure to air*
Alkaptonuria - Congenital deficiency of homogentisic acid (no degradation of Tyr --> fumarate)
101
Albinism
Lack of: 1. Tyrosinase (no melanin from Tyr) 2. Defective tyrosine transporters (dec Tyr = dec melanin)
102
Lens subluxation atherosclerosis MR Tall w/ kyphosis
Homocystinuria 1. Cystathione synthase deficiency - Inc cysteine, B12, Folate 2. Dec affinity of cystathione synthase - Inc B6 3. Homocysteine methyltransferase deficiency - B12
103
Cystinuria
AR Defect in PCT Cysteine, ornithine, lys, arg transporter Can --> cystine kidney stones (staghorn calculi) Tx: = acetazolamide to alkalinize urine
104
Maple syrup urine disease
``` Blocked degradation of BRANCHED A.A. Ile Leu Val "I Love Vermont maple syrup" ``` Severe CNS, MR, death
105
Hartnup disease
AR Defective NEUTRAL A.A. transporter Renal or intestinal epithelial cells Tryptophan excretion Dec abs in gut PELLAGRA
106
Von Gierke's Disease (Type I glycogen)
Deficiency = Glu-6-Phosphatase Severe fasting hypoglycemia Hepatomegaly (glycogen storage) Inc blod lactate
107
Pompe's Disease (Type II glycogen)
Deficiency = Lysosomal alpha-1,4-glucosidase Pompe-Pump Cardiomegaly
108
Cori's Disease (Type II glycogen)
Deficiency = Debranching alpha-1,6-glucosidase Milder type I w/ NORMAL lactate
109
McArdle's Disease (type IV glycogen)
Deficiency = skeletal muscle glycogen phosphorylase McArdle-Muscle Painful muscle cramps w/ exercise Myoglobinuria High glycogen in muscle that can't be broken-down
110
Fabry's
``` Deficiency = alpha-galactosidase Accumulate = Ceramide trihexose ``` ONLY non AR lysosomal storage disorder = XR Sx: Peripheral neuropathy Angiokeratomas
111
Aseptic necrosis of femur, crumpled MOs, hepatosplenomegaly
Gaucher's - Deficiency = Glucocerebrosidase - Accumulate = Glucocerebroside ****Gaucher's cells = crumpled tissue paper MO***
112
Cherry-red spot on the macula + Hepatosplenomegaly (vs. Tay-Sachs) Foam Cells
Niemann-Pick - Deficiency = Sphingomyelinase - Accumulate = Sphingomyelin "No man Picks his nose with his Sphinger"
113
Cherry-red sopt on the macula W/O hepatosplenomegaly | Lysosomes w/ onion skin
Tay-SaX - Deficiency = HeXosamidase A - Accumulate = GM2 ganglioside - hepatosplenomegaly (vs. Niemann-Pick)
114
Peripheral neuropathy Optic atrophy Globoid cells
Krabbe's Disease - Deficiency = B-Klactocerebrosidase - Accumulate = Kalactocerebroside
115
Central + peripheral demyelination w/ ataxia | Dementia
Metachromatic Leukodystrophy - Deficiency = Arylsulfatase A - Accumulates = Cerebroside sulfate
116
Gargoylism Corneal clouding Airway obstruction Corneal clouding
Hurler's - Deficiency = alpha-L-iduronidase - Accumulate = Heparan sulfate, dermatan sulfate - Corneal clouding (vs. Hunter's)
117
Hunter's Syndrome
``` Deficiency = Iduronate sulfatase Accumulate = Heparan sulfate, dermatan sulfate ``` Sx: Mild Hurler's + AGGRESSIVE BEHAVIOR NO corneal clouding (vs. Hurler's)
118
Abetalipoproteinemia
Hereditary inability to synthesize lipoproteins - deficiencies in apoB-100 & apoB-48 Accumulation in enterocytes - can't export lipids as chylomicrons ``` Sx: FTT Steatorrhea Night blindness Acanthocytosis Ataxia ```
119
Hypertriglyceridemia
Inc VLDL Inc blood TGs Hepatic OVERPRODUCTION of VLDL --> pancreatitis
120
Familial Hypercholesterolinemia
Inc LDL Inc blood cholesterol AD dec/absent LDL receptors - -> accelerated atherosclerosis - -> tendon xanthomas (achilles) - -> corneal arcus
121
Hyperchylomicronemia
Inc Chylomicrons Inc blood cholesterol & TGs LPL deficiency OR altered aopC-II Sx: Pancreatitis Hepatosplenomegaly Eruptive/pruritic xanthomas (NO risk for atherosclerosis)
122
DNA Methylation
Mute transcription
123
DNA Methylation
Mute transcription
124
Histone Acetylation
Euchromatin = active
125
Histone Acetylation
Euchromatin = active
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