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103 Cards in this Set

  • Front
  • Back
What gives DNA a negative charge?
Phosphate
What gives DNA a positive charge?
Lysine and Argenine
What does methylation do to DNA?
Makes DNA mute
What is hypermethylation?
Inactivates transcription of DNA
What is histone acetylation?
Makes DNA active
Which bonds increase the melting temp of DNA?
G-C bonds (contain 3 H-bonds)
Amino acids needed for purine synthesis?
Glycine, Aspartate, Glutamine

(also need THF4)
Rate limiting enzyme for purines?
Glutamine PRPP aminotransferease
Rate limiting enzyme for pyrimidines?
CPS II
What is Orotic Aciduria?
Inability to convert orotic acid to UMP due to defect in Orotic Acid Phosphoribosyltransferase or Orotidine 5'-phosphate decarboxylase.
What are the symptoms of Orotic Aciduria?
Megaloblastic Anemia (does not improve w/folate or B12)
Failure to Thrive
Orotic Acid in Urine
(No increase in NH4)
Treatment for Orotic Aciduria?
Oral Uridine Administration
Hydroxyurea MOA?
Inhibits Ribonucleotide reductase

(used for Sickle Cell Pts)
Difference b/w CPSI and CPS II
CPS I - mitochondria, urea cycle, Nitrogen for NH4

CPS II - Cytosol, Pyrimidine Synthesis, Nitrogen from Glutamine
Adenosine Deaminase deficiencey
SCID
Excess ATP causes feedback inhibition of Ribonucleotide Reductase--> prevents DNA synthesis-->decreased lympocytes
Triad Symptoms of SCID?
Failure to thrive, Severe Recurrent Infections, Chronic Diarrhea

(absence of thymic shadow and decrease lymphocyte count)
Lesch-Nyhan Syndrome
Defective Purine salvage pathway due to lack of HGPRT which converts hypoxanthine to IMP and Guanine to GMP
Excess Uric acid production
Findings of Lesch-Nyhan Syndrome?
Retardation, self-mutilation, agression, hyperuricemia, gout, choreoathetosis
Nonsense mutation?
Early stop codon

"STOP the nonsense"
Missense mutation?
Changed amino acid
Frameshift mutation?
Leads to misreading of all nucleotides downstream.

Can cause a truncated, non functional protein
Silent mutation?
Change in base in 3rd position

tRNA Wobble effect
DNA topoisomerases function?
Create nick in helix to relieve supercoil
DNA polymerase Alpha function?
Replicates lagging strand & synthesizes RNA primer
DNA polymerase Beta & Epsilon function?
Repair DNA
DNA polymerase Gamma function?
Replicate mitochondrial DNA
DNA polymerase Delta function?
Replicate leading strand DNA
Xeroderma Pigmentosum defect?
Defect in nucleotide excision repair, which prevents repair of Thymidine dimers due to UV light exposure.
What type of DNA repair mechanism is defective in HNPCC?
Mismatch Repair
What type of DNA repair mechanism is defective in Ataxia Telangiectasia?
Nonhomologous end joining
Types of RNA
rRNA (polymerase 1) most abundant
mRNA (polymerase 2) longest type
tRNA (polymerase 3) smallest type
Where are tRNA and mRNA synthesized?
Nucleoplasm
Where is rRNA synthesized?
Nucleolus
Alpha Amanitin function?
Mushroom toxin that can inhibit RNA Polymerase II.

Causes liver failure.
What cells is ptotein synthesis completed in?
Fibroblasts, Hepatocytes, Plasma Cells
Stable/Quiescent Cells?
Lymphocytes and Hepatocytes

Enter G1 when stimulated
Permanent Cells?
Neurons, skeletal & cardiac muscle, RBC's

Divide from stem cells
Which Amino Acids are modified by the Golgi?
Serine, Threonine, Asparagine, Tyronine
What is COP I?
Retrograde trafficking protein.

From Golgi-->ER
What is COP II?
Anterograde trafficking protein

From RER-->cis-Golgi
What is I-cell Disease?
Failure of addition of mannose-6-phosphate to lysosome proteins

Enzymes are secreted outside of the cell instead of lysosome.
What is the defect in Chediak-Higashi syndrome?
Decreased fusion of phagososmes and lysosomes
What is the triad of symptoms in Chediak-Higashi?
Pyogenic Infections
Partial Albinism
Peripheral Neuropathy
Kartagener's Syndrome?
Immotile cilia, dynenin arm defect
Results in infertility, bronchiectasis, and recurrent sinusitis

Associated w/Situs Inversus
Collagen Synthesis?
Synthesis in RER - Preprocollagen- Need Glysine
Hydroxylation (ER) - need Vitamin C
Glycosylation (ER) - formation of procollagen (tripple helix)
Exocytosis
Proteolytic Processing - forms tropocollagen
Cross Linking
Osteogenesis Imperfecta?
Type I collagen defect (AD)
Multiple Fractures
Blue Sclerae
Hearing Loss
Dental Imperfection (lack of dentin)
Ehlers-Danlos Syndrome?
Type III Collagen Defect (AD/AR)
Hyperextensible Skin
Tendency to Bleed
Hypermobile Joints
Alport Syndrome?
Type IV Collagen Defect
X-linked Recessive
Nephritis
Deafness
Ocular Disturbances
What is Pleiotropy?
One gene has more than 1 effect on a person's phenotype.

Ex. PKU
Dominant Negative Mutation?
Heterozygote produces a non-functional protein that prevents the normal gene product from functioning.
What is Heteroplasmy?
Normal and mutated mtDNA

Variable expression in mitochondrial inherited disease
What is Hypophosphatemic Rickets?
Increase phosphate wasting at proximal tubule.

X-linked Dominant
Mitochondrial Myopathies?
Leber's Hereditary Optic Neuropathy
Myoclonic Epilepsy
Mitochondrial Encephalopathy
"Ragged Red Fibers" on microscopy
Achondroplasia
Defect in FGF Receptor 3 (AD)
Dwarfism
Short extremities, normal head and trunk
Advanced Paternal Age
ADPKD
Bilateral (AD)
Mutation in PKD1 (Ch. 16)
Associated w/Polycystic Liver Disease, Berry Aneurysms, Mitral Valve Prolapse
Familial Adenomatous Polyposis
Colon covered w/adenomatous polyps after puberty (AD)
APC Gene (Ch. 5)
progresses to Colon CA unless resected
Familial Hypercholesterolemia
(Hyperlipidemia Type IIa)
Elevated LDL due to defective or absent receptor. (AD)
Atherscleotic Disease
Tendon Xanthomas
MI before 20y/o
Hereditary Hemorrhagic Telangiectasia
(Osler-Weber-Rendu Syndrome)
Disorder of BV's (AD)
Telengectasia
Recurrent Epistaxis
Skin Discoloration
Arteriovenous Malformations
Hereditary Spherocytosis
Spectin or Ankyrin Defect (AD)
Hemolytic Anemia
Splenectomy is curative
Dx w/osmotic fragility test
Huntington's Disease
Decreased GABA & Ach (AD)
Affects Basal Ganglia
CAG Repeat (Ch. 4)
Marfan's Syndrome
Fibrillin Gene Mutation (AD)
Long Extremeties
Cystic Medial Necrosis of Aorta
Floppy Mitral Valve
Sublexation of lenses
Berry Aneurysms
MEN
Family tumors of endocrine glands (AD)
MEN 2A and 2B associated w/ret gene
NFT 1
(von Recklinghausen's Disease)
Cafe-au-lait spots (AD)
neural tumors
Lisch nodules
Ch. 17 (long arm)
NFT 2
Bilateral acoustic schwannomas (AD)
Juvenille Cataracts
Ch. 22
Tuberous Sclerosis
"Ash leaf spots" on skin (AD)
Cortical/retinal harmartomas
Seizures, MR
Cardiac Rhabdomyomas, Astrocytomas, Renal Angiolypomas
Imcomplete Penetrance
von Hippel-Lindau Disease
Deletion of VHL gene on Ch. 3 (AD)
Constituative activation of HIF transcription factor & activation of angiogenic growth factors
Bilateral Renal Cell Carcinoma
Fragile X Syndrome
X-linked
Xtra-large testes, jaws, & ears
FMR1 Gene
#1 Cause of inherited MR
Trinucleotide Repeat Disorders
Fragile X (CGG)
Friedricks Ataxia (CAA)
Huntington's (CAG)
Mytotonic Dystrophy (CTG)
Cri-du-chat Syndrome
Microdeletion of short arm of Ch.5
VSD
Microcephaly
MR
Williams Syndrome
Microdeletion of long arm of Ch. 7
"Elfin facies"
MR
Hypercalcemia
Extreme friendliness w/strangers
Pyruvate Dehydrogenase Deficiency
Causes Neurologic Defects
Increase Intake of Ketogenic Amines (Lysine & Leucine)
or Increase High fat content foods
G6PD Deficiency
Decreased NADPH in RBC's leads to hemolytic Anemia (AR)
Poor RBC defense to oxidizing agents
Heinz Bodies & Bite Cells
Fava Beans, Sulfonamides, Primaqquine, & Anti-Tb drugs precipitate problems
Essential Fructosuria
Deficiency in Fructokinase (AR)
Fructose appears in blood & urine
Fructose Intolerance
Deficiency in Aldolase B (AR)
Fructose-1-phosphate accumulates
Decrease in available phosphate
Inhibition of glycongenolysis & gluconeogenesis
Hypoclycemia, jaundice, cirrhosis, Vomiting
Tx = decrease fructose & sucrose
Galactokinase Deficiency
Defeciency in Galactokinase (AR)
Galactose in Blood/Urine
Failure to develop social smile, inability to track objects, infantile cataracts
Classic Galactosemia
Deficiency in Galactose-1-phosphate Uridyltransferase (AR)
Failure to thrive, jaundice, infantile cataracts, Hepatomegaly, MR
Exclude galactose and lactose from diet
What amino acids help w/nuclear localization signals?
Lysine, Argenine, Proline
What helps to trap ammonia in the gut?
Lactulose
Ornithine Transcarbamoylase Deficiency
X-linked Recessive
Body can't eliminate ammonia
Orotic Acid in blood in urine
Hyperammonemia
Decreased BUN
Most common urea cycle disorder
Phenylketonuria (PKU)
Decreased Phenalanine Hydroxylase or decreased tetrahydrobiopterin cofactor
MR, Growth Retardation, Seizures, fair skin, eczema, Musty Body Odor
Tx= Decrease Phenylalanine & increase tyrosine
Alkaptonuria
Deficiency of Homogentisic Acid Oxidase (AR)
Dark Connective tissue, Brown sclera, Black urine, Arthralgias
Albinism
Deficiency in Tyrosinase (AR)
or Defective Tyrosine Transporters
Can result from lack of migration of neural crest cells
Homocystinuria Causes
AR
Cystathionine Synthase Deficiency or Decreased Affinity of cystathionine synthase for B6 or Decreased Homocysteine Methyltransferase
Homocystinuria Effects?
MR, osteoporosis, in homocysteine in urine, lens subluxation, atherosclerosis
Tx= Decrease Methionine, Increase B12, B6, Folate, & Cysteine
Cystinuria
Defect of renal tubular transporter for cysteine, ornithine, lysine, & argenine
Can cause kidney stones
Tx=Acetazolamide to alkalinize urine
Maple Syrup Urine Disease
Blocked Degradation of branched chain amino acids (Ile, Leu, Val)
Decreased Alpha-Keotacid dehydrogenase
CNS defects, MR, and death
Hartnup Disease
Defective Neutral Amino acid transporter on renal and intestinal epithelial cells
Tryptophan excretion in urine
Leads to Pellagra (Dermatitis, Diarrhea, Deentia)
VonGirke's Disease
(Type I)
Severe fasting hypoglycemia, Increased glycogen in liver, increase blood lactate, increase uric acid, hepatomegaly
Deficiency: Glucose-6-phosphatase
Pompe's Disease
(Type II)
Cardiomegaly
Deficiency: Lysossomal Alpha-1,4-glucosidase (acid maltase)
Pompe's trashes the heart, liver, and muscle
Cori's Disease
(Type III)
Milder form of Type I w/ normal blood lactate levels
Deficiency: Debranching enzyme (alpha-1,6-glucosidase)
Gluconeogenesis is intact
McArdle's Disease
(Type V)
Increased glycogen in muscle, but cant break it down
Painful cramps, myoglobinuria, rhabdomyolysis
Defect: Skeletal muscle glycogen phosphorylase
Adult Pompe's
Diaphragm Weakness and respiratory failure
Fabry's Disease
Peripheral Neuropathy hands/feet (XR)
Angiokeratomas
Progressive renal failure
Deficiency: Alpha glactosidase A
Accumulate: Ceramide trihexoside
Gaucher's Disease
(Most Common)
HSM, Aseptic necrosis of femur, Gaucher's cells (look like crumpled tissue paper)
(AR)
Deficiency: Glucocerbrosidase
Accumulate: Glucocerboside
Neimann-Pick Disease
Progressive neurodegeneration, HSM, cherry red spot on macula, foam cells, Early Death (AR)
Deficiency: Sphingomyelinase
Accumulate: Sphingomyelin
Tay-Sachs Disease
Progressive neurodegeneration, lysosomes w/onion skin, cherry red spot on macula, foam cells, Early Death (AR)
Deficiency: Hexosaminidase A
Accumulate: GM2 ganglioside
Krabbe's Disease
Peripheral Neruopathy, developmental delay, optic atrophy, globoid cells, Early Death (AR)
Deficiency: Beta-galactocerbrosidase
Accumulate: Galactocerbroside
Metachromic Leukodystrophy
Central and peripheral demyelmination w/ataxia & dementia (AR)
Deficiency: Arylsulfatase A
Accumulate: Cerebroside Sulfate
Hurler's Syndrome
Gargoylism, Airway Obstruction, Corneal Clouding, HSM, & MR (AR)
Deficiency: Alpha-L-iduronidase
Accumulate: Heparin Sulfate & Dermatan Sulfate
Scheie's Syndrome
Milder form of Hurler's syndrome
Conreal clouding
No MR
Hunter's Syndrome
Mild Hurler's + agressive behavior (XR)
No corneal clouding
MR
Deficiency: Iduronate Sulfatase
Accumulate: heparin & dermatan sulfate
Abetalipoproteinemia
Inability to synthesize lipoproteins Deficiencies in apoB-100 & apoB-48 (AR)
Accumulation w/in enterocytes
Inability to export lipid as chylomicrons
Abetalipoproteinemia Signs
Failure to thrive, steatorrhea, acanthocytosis (spiky plasma membrane of RBC's), Ataxia, night blindness
Tx=Vitamin E