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110 Cards in this Set
- Front
- Back
What are the differences between carbamoyl phosphate synthetase (CPS) I & II
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- Location: I [mito], II [cytosol]
- Pathway: I [urea cycle], II [pyrimidine synthesis] - Nitrogen source: I [ammonia], II [glutamine] |
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What is the rate-limiting step in purine synthesis?
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Glutamine PRPP aminotransferase
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What is the rate-limiting step in pyrimidine synthesis?
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CPS II
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HYQ: What are the sources of carbons in the formation pf purines?
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C: CO2, Glycine, THF
N: Aspartate, CO2 |
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HYQ: What are the sources of carbons in pyrimidine synthesis?
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C: Asparate, CO2
N: Glutamine |
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What accounts for the positive charge of histones?
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Lysine, Arginine
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What accounts for the negative charge of DNA?
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Phosphate groups
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How many adenine residues are found in a molecule of DNA if one strand contains A=2000, G=500, C=1500, T=1000?
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A (2000) + T (1000) = 3000
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What strand of DNA nucleotides opposes this DNA strand: 5' - ATTGCGTA-3'?
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5' - TACGCAAT - 3'
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Which medication matches the following statement?
Inhibits ribonucleotide reductase |
Hydroxyurea
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Which medication matches the following statement?
Inhibits dihydrofolate reductase |
MTX
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Which medication matches the following statement?
Inhibits thymidylate synthase |
5-FU
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Which medication matches the following statement?
Inhibits inosine monophosphate dehydrogenase |
Mycophenalate
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Which medication matches the following statement?
Inhibits PRPP synthetase |
6-MP
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What are the characteristic features of orotic aciduria?
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- Inc orotic acid in urine
- Megaloblastic anemia (not improved by B12 or folic acid) - Failure to thrive - No hyperammonemia |
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HYQ: How does UV light damage DNA?
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Creates thymine dimers on same strand of DNA
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What eukaryotic DNA polymerase matches the following description?
Replicates lagging strand, synthesizes RNA primer |
Alpha
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What eukaryotic DNA polymerase matches the following description?
Repairs DNA |
Beta, Epsilon
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What eukaryotic DNA polymerase matches the following description?
Replicates mitochondrial DNA |
Gamma
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What eukaryotic DNA polymerase matches the following description?
Replicates leading strand DNA |
Delta
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Which antibiotic matches the following description?
Inhibits 50s peptidyltransferase |
Streptogamins, Chloramphenicol
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Which antibiotic matches the following description?
Binds 50s, blocking translocation |
Macrolides/Linezolid, Clindamycin
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Which antibiotic matches the following description?
Bind 30s, preventing attachment of tRNA |
Tetracycline
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Which antibiotic matches the following description?
Inhibits prokaryotic RNA polymerase |
Rifampin
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Which antibiotic matches the following description?
Inhibits prokaryotic topoisomerase |
Fluoroquinolones
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Which antibiotic matches the following description?
Inhibits prokaryotic dihydrofolate reductase |
Trimethoprim
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What are the 3 different mechanisms cells employ to break down proteins?
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1. Ubiquitin mech
2. Lysosomal degradation mech 3. Ca2+ dependent enzyme mech |
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What enzyme catalyzes peptide bond formation during protein synthesis?
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Peptidyl transferase/Ribosomal rRNA/Ribozyme
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What enzyme matches amino acids to tRNA (& is responsible for tRNA charging)?
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Aminoacyl tRNA synthetase
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What are the mRNA stop codons?
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UAG, UGA, UAA
[U Are Gone, U Go Away, U Are Away] |
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What are the different RNA polymerases in eukaryotes?
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- RNA pol I: Codes for rRNA
- RNA pol II: Transcribes mRNA - RNA pol III: Transcribes tRNA |
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HYQ: What amino acid frequently has more coding sequences in the mRNA than are represented in the peptide that is created from that mRNA?
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Methionine
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HYQ: How is hnRNA processed before it leaves the nucleus?
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1. Gets 5' cap
2. Poly A tail 3. Splicing out of introns |
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What is the characteristic sequence of the promoter region? What does a mutation in the sequence cause?
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- 25 TATA box, - 75 CAT box
- Dec in amt of gene that is transcribed |
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What enzyme is deficient in Lesch-Nyhan syndrome? What is the treatment?
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- HGPRT
- Allopurinol |
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What structural motifs allow for proteins to bind to DNA?
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- Helix turn Helix
- Helix loop Helix - Leucine zippers - Zinc fingers |
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Mitochondrial inheritance defects
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1. Mitochondrial myopathies (ragged red muscle fibers seen on biopsy!)
2. Leber's hereditary optic neuropathy 3. Leigh syndrome (subacute sclerosing encephalopathy) |
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What is the frequency of the BB phenotype & the Bb phenotype if the frequency of allele B is 70%?
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B= 70% so (1-.7 = 0.3 = b)
Freq of BB is p^2 = (0.7)^2 = 0.49 or 49% Freq of Bb is 2pq = 2(0.7)(0.3) = 0.42 or 42% |
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What autosomal dominant dz fits the following statement?
A/w floppy mitral valve, dissecting aortic aneurysm, berry aneurysm |
Marfan's
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What autosomal dominant dz fits the following statement?
A/w mitral valve prolapse, liver dz, berry aneurysms |
ADPKD
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What autosomal dominant dz fits the following statement?
Neural tumors & pigmented iris hamartomas |
NF 1
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What autosomal dominant dz fits the following statement?
Very strong a/w colon cancer |
FAP
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What autosomal dominant dz fits the following statement?
MI before 20yo |
Familial Hypercholesterolemia (Hyperlipidemia type IIA)
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What autosomal dominant dz fits the following statement?
Hemangioblastomas of retina/cerebellum/medulla |
Von Hippel Lindau dz
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What autosomal dominant dz fits the following statement?
Inc MCHC, hemolytic anemia |
Hereditary spherocytosis
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What autosomal dominant dz fits the following statement?
Bilateral acoustic neuromas |
NF 2
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What autosomal dominant dz fits the following statement?
Facial lesions, seizure d/o, cancer risk |
Tuberous sclerosis
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What autosomal dominant dz fits the following statement?
Caudate atrophy, dementia |
Huntington's
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What autosomal dominant dz fits the following statement?
Cystic medial necrosis of the aorta |
Marfan's
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What autosomal dominant dz fits the following statement?
Defect of fibroblast growth factor (FGF) receptor 3 |
Achondroplasia
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List of AD dz
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1. ADPKD (Adult)
2. Hereditary spherocytosis 3. Familial adenomatous polyposis 4. Huntington's 5. Von Recklinghausen's 6. Von Hippel Lindau 7. Familial hypercholesterolemia 8. Marfan's |
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List of AR dz
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1. Glycogen storage dz
2. ARPKD (infant) 3. PKU 4. Thalassemias 5. Sickle cell 6. Mucopolysaccharidoses (except Hunter's) 7. Sphingolipidosis 8. Cystic fibrosis 9. hemochromatosis |
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List of X linked recessive
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1. Fragile x
2. Duchenne's MD 3. Lesch-Nyhan 4. Bruton's 5. Wiskott Aldrich 6. hemophilia 7. G6PD deficiency |
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Which lysosomal storage dz is a/w renal failure
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Fabry's dz (therefore treat w/ dialysis)
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What are the only 2 x linked recessive lysosomal storage dz? What are the method of inheritance of the others?
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1. Fabry's, Hunter's
2. AR |
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What is the most common lysosomal storage dz?
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Gaucher's
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Which lysosomal storage dz is a demyelinating dz?
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Metachromatic leukodystrophy
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Which lysosomal storage dz are a/w an early death (usually by age 3)?
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1. Tay sachs
2. Niemann Pick 3. Krabbe's |
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How might corneal clouding & mental retardation help distinguish btwn the mucopolysaccharidoses?
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- Hurler's: (+) cc, (+) MR
- Hunter's: (-) cc, (+) MR - Scheie's: (+) cc, (-) MR [milder Hurler's] - I cell: (+) cc, +/- MR |
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Which lysosomal storage dz is characterized by the following enzyme deficiencies?
alpha L iduronidase |
Hurler's, Scheie's
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Which lysosomal storage dz is characterized by the following enzyme deficiencies?
Iduronate sulfatase |
Hunter's
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Which lysosomal storage dz is characterized by the following enzyme deficiencies?
Arylsulfatase A |
Metachromatic leukodystrophy
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Which lysosomal storage dz is characterized by the following enzyme deficiencies?
alpha galactosidase A |
Fabry's
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Which lysosomal storage dz is characterized by the following enzyme deficiencies?
Galactocerebrosidase --> galactocerebroside accumulation |
Krabbe's
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Which lysosomal storage dz is characterized by the following enzyme deficiencies?
Beta glucocerebrosidase --> glucocerebroside accumulation |
Gaucher's
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Which lysosomal storage dz is characterized by the following enzyme deficiencies?
Hexosaminidase |
Tachy sachs
{Tay saX, heXo} |
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Which lysosomal storage dz is characterized by the following enzyme deficiencies?
Sphingomyelinase --> sphingomyelin accumulation |
Niemann Pick
{Don't Pick your nose w/ your Sphinger} |
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Characterized by accumulation of GM2 ganglioside
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Tay sachs
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Characterized by accumulation of dermatin sulfat
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Mucoplysaccharidoses
1. Hurler's 2. Hunter's 3. Scheie's |
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Which are particularly common among Ashkenazi jews?
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1. Tay sachs
2. Niemann Pick 3. Some form of Gaucher's |
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Which has characteristic "crinkled paper cytoplasm"?
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Gaucher's
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What is the differential diagnosis for a cherry red spot on the retina?
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1. Niemann Pick
2. Tay sachs 3. Central retinal artery occlusion |
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What is the probability that a female heterozygous for an x linked dz will pass it on to her son?
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- If already born: 50%
- If not born/don't know gender: 25% |
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What probability that a female heterozygous for an x linked dz that mates w/ a normal male will have a carrier daughter?
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- If already born: 50%
- If not born/don't know gender: 25% |
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What is the probability that a female carrier of an x linked dz will have a child w/ that dz assuming she mates w/ a normal mate?
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25%
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If aa symbolizes a recessive dz, what is the likelihood that parents Aa & Aa will have a phenotypically normal child?
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25%
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Cystic fibrosis is an AR d/o. 2 parents that are heterozygous for CF have a normal, nonaffected child. What is the probability that the child is homozygous normal?
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33.3% (1/3)
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Upon examination of a pedigree, you note that both males & females are affected w/ a dz in every generation. What type of genetic dz is this?
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AD
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What is the frequency of the Aa genotype & the AA genotype if the frequency of allele A is 0.95?
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Frequency of a = 0.05
Hetero frequency = 2(0.05)(0.95) = 2pq = 0.095 or 10% Homo frequenc (A) = (0.95)^2 = 0.9 or 90% |
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If 49% of a particular population is homozygous for a curly hair gene that is dominant to a straight hair gene, what percentage of the population has curly hair?
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p^2 = 0.49
p = 0.7 therefore q = 0.3 (straight hair gene) 2(0.7)(0.3) = 0.42 or 42% 42% + 49% = 91% |
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What is the name of the genetic dz that fits the following description?
Cafe au lait spots + soft tissue growths |
NF 1
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What is the name of the genetic dz that fits the following description?
Macroorchidism & autism |
Fragile x
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What is the name of the genetic dz that fits the following description?
Endocardial cushion defects are common |
Down's
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What is the name of the genetic dz that fits the following description?
Recurrent pulmonary infections, steatorrhea |
Cystic fibrosis
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What is the name of the genetic dz that fits the following description?
Multiple fractures, easily confused w/child abuse |
Osteogenesis imperfecta
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What is the name of the genetic dz that fits the following description?
A/w Alzheimer's after 35 yo |
Down's
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What is the name of the genetic dz that fits the following description?
Prone to bilateral acoustic Schwannomas |
NF2
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What is the name of the genetic dz that fits the following description?
Excess fibro-fatty tissue deposits amongst muscle |
Duchenne's MD
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What test is used to diagnose cystic fibrosis? Which gene is defective?
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1. Chloride sweat test
2. CFTR gene |
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What is the difference between Southern blot, Northern blot, Western blot?
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- Southern blot: Sample (DNA); Probe (DNA)
- Northern: Sample (RNA); Probe (DNA) - Western: Sample (Protein); Probe (Ab) |
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HYQ: 2 pts have the same mutation on chromosome 15 but have different phenotypic expressions. One pt received the mutation from the father while the other received the mutation from the mother. What is this an example of?
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Imprinting
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HYQ: Frequency of CFTR mutation X in pts w/CF is 0.1. CF can be caused by either mutation X or mutation Y in the CFTR gene. What percentage of CF pts are homozygotes for mutation Y?
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Frequency (x) = 0.
Frequency (y) = 0.9 (0.9)^2 = 81% |
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What drugs act on microtubules?
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- -bendazoles
- -taxels - Griseofulvin - Vincristine/vinblastine - Colchicine |
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What finds are a/w Ehlers-Danlos syndrome?
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- Hyperextensible skin
- Inc bleeding tendency - Hypermobile joints - Berry aneurysm |
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Which arachidonic acid product causes the following effect?
Inc bronchial tone |
- Leukotrienes
- Thromboxane |
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Which arachidonic acid product causes the following effect?
Dec bronchial tone |
- Prostacyclins
- Prostaglandins |
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Which arachidonic acid product causes the following effect?
Inc platelet aggregation |
Thromboxane
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Which arachidonic acid product causes the following effect?
Dec platelet aggregation |
Prostacyclin
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Which arachidonic acid product causes the following effect?
Inc uterine tone |
Prostaglandins
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Which arachidonic acid product causes the following effect?
Dec uterine tone |
Prostacyclin
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Which arachidonic acid product causes the following effect?
Inc vascular tone |
Thromboxane
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Which arachidonic acid product causes the following effect?
Dec vascular tone |
- Prostaglandin
- Prostacyclin |
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What are the 2 most abundant substances in plasma membrane?
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- Cholesterol
- Phospholipid |
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What provides the structural framework for DNA & the nuclear envelope?
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Laminins A, B, C
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What drugs act on the arachidonic acid product pathway? What enzymes do they effect?
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1. Corticosteroids: Phospholipase A2
2. Zileuton: Lipoxgenase 3. Zafirlukast & Montelukast: Leukotriene receptor 4. NSAIDS, Acetaminophen, Aspirin & COX 2 inhib: COX |
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HYQ: In trying to determine the genomic location of genes x, y & z, you cut multiple copies of the gene w/ a variety of different endonucleases. The following proteins are expressed x, xz, y, & z. What are the most likely relative locations of genes x, y & z?
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X & z are close to each other; Y isn't close to any other
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Describe the process of leukocyte extravasation.
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- Rolling: Selectin A mediated
- Tight binding: Integrins - Diapedesis: PE-CAM - Migration: Chemotactic factors (IL-8, LTB4, C5a, Kallikrein) |
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How are molecules transported into the nucleus?
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Nuclear localization signals:
Rich in Lysine, Arginine, Proline |
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What histologic features are seen in apoptotic liver cells?
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- Cellular shrinkage
- Nuclear shrinkage & basophilia (pyknosis) - Membrane blebbing - Pyknotic nuclear fragmentation - Nuclear fading - Formation of apoptotic bodies |
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What are the signaling pathway effects of activating Gq? What are the effects of activating Gs?
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Gq "qc":
Activates PLC --> IP3 --> Inc Ca intracell & PLC --> DAG --> Activates PKC Gs: Stim adenylyl cyclase (use ATP to make cAMP) --> cAMP activates PKA |