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USMLE > Things I just can't seem to remember for STEP 1 > Flashcards

Things I just can't seem to remember for STEP 1 Flashcards

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1
Q

What structures form the Hesselbach’s triangle

A
  • Inferior epigastric artery
  • Inguinal ligament
    Lateral border of rectus abdomens
  • Direct inguinal hernias
    Medial inferior gastric artery
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2
Q

Amino acids necessary for Purine

A

“GAG”

Glycine
Aspartate
Glutamine

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3
Q

Enzyme that converts ribonucleotides to deoxyribonucleotides

A

Ribonucleotide reductase

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4
Q

What is the rate limiting step of Pyrimidine base produciton

A

Carbamoyl Phosphate synthetase II

requires 2ATP molecules

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5
Q

What is the rate limiting enzyme of purine synthesis

A

Glutamine phosphoribosylpyrophosphate (PRPP) amidotransferase

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6
Q

DNA Polymerase in prokaryotes and their function

A

DNA polymerase III: leading and lagging strand elongation
(5’–>3’)
- exonuclease activity proof reads (3’-5’)

DNA polymerase I: excises RNA primer and replaces it with DNA
-excises RNA primer in a 5’-3’

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7
Q

DNA polymerases in Eukaryotes and their functions

A

DNA polymerase alpha: puts down RNA primer and makes okazaki fragments on lagging strand

DNA polymerase beta: DNA repair

DNA polymerase delta: leading strand

DNA polymerase gamma: mitochondrial DNA

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8
Q

mutation in DNA is transversion vs. transition

A

Transition – purine to purine (or pyrimidine to pyrimidine)

Transversion – purine to pyrimidine (vice versa)

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9
Q

Bloom syndrome

A

mutation of helicase
* blocks DNA replication and repair

clinically:

  • hypersensitivity to sunlight
  • preceptibility to cancers (leukemias)
  • immunosuppression
  • facial anomilities
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10
Q

What is the start codon and who are the stop codons

A

Start codon: AUG – Methionine

Stop codon:
UGA – U Go Away
UAA– U Are Away
UAG— U Are Gone

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11
Q

Causes of meningitis in Newborn (6months)

A

Group B strep
E coli
Listeria monocytogenes

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12
Q

Causes of meningitis in Children (6m-6years)

A

S. pneumoniae
N. meningitidis
H. influenza type B
Enterovirus

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13
Q

Causes of meningitis 6-60years old

A

N. meningitidis ( #1 in teens)
S. pneumoniae
Enteroviruses
HSV

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14
Q

Causes of meningitis 60+ years old

A

S. pneumoniae
Gram negative rods
Listeria

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15
Q

What is the enzyme that attaches an amino acid to the tRNA

A

aminoacyl- tRNA synthetase

_attaches amino acid to 3’ CCA sequence
“Can Carry Amino”

If charged an incorrect amino acid, bond is hydrolyzed and aminoacyl- tRNA synthetase will put on the correct one

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16
Q

Triad of tuberous sclerosis

A

seizures, intellectual disability, angiofibromas

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17
Q

Enzyme missing in I-cell disease

A

N-acetylglucosaminyl-1-phosphotransferase — failure of golgi to phosphorylate mannose 6 phosphate. Proteins are secreted rather than going to lysosomes

  • course facial features, clouded corneas, restricted joint movements, and high plasma levels of lysosomal enzymes.
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18
Q

Menkes disease

A

X linked recessive connective tissue disease caused by impaired copper absorption and transport

Defective Menkes protein : ATP7A (recall 7B is Wilson’s disease GI chapter)

clinical presentation:

  • kinky hair
  • Growth retardation
  • Hypotonia
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19
Q

Biochemical cause of Marfan?

A

defect in Fibrillin – a glycoprotein made by fibroblasts that forms a sheath around elastin

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20
Q

What bug causes Q fever?

A

Coxiella burnetii

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21
Q

Why can’t muscle cells completely break down glycogen? (glycogenolysis)

A

Muscle cells do not posses Glucose -6-phosphatase. This does not mean that muscle cells cannot undergo gluconeogenesis. They can get up to Glucose-6 phosphate and then use that in glycolysis/ energy but they cannot distribute glucose to other organisms ( like the liver can)

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22
Q

What enzyme catalyzes the rate limiting step in carbohydrate digestion?

A

oligosaccharide hydrolases – found on intestinal brush border

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23
Q

Describe Pyruvate Dehydrogenase Complex

  1. mechanism
  2. findings
  3. treatment if congenital
  4. can it be acquired?
A

X- linked build up of pyruvate that gets shunted to Lactate and Alanine

neurological defects, lactic acidosis, high serum alanine starting in infancy

Increase intake of ketogenic nutrients ( high fats, lysine, leucine)

Yes, arsenic poisoning, thiamine deficiency (alcoholics)

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24
Q

What causes Phenylketonuria and what are the physical findings?

Tx?

A

Loss of phenylalanine hydroxylase or it’s co-factor tetrahydrobiopterin (BH4)

Autosomal recessive

Excess phenylalanine– excess phenylketones in urine
+ neurotoxic effect

Findings: Intellectual disability, growth retardation, seizures, fair skin (melanin is in phenylalanine pathway), eczema, musty body odor

Tx: decrease phenylalanine and increase tyrosine in diet, tetrahjydrobiopterin supplementation

AVOID ARTIFICIAL SWEETENER ASPARTAME

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25
What is the name of the disease that is deficient in homogentisate oxidase? Presentation?
Alkaptonuria (ochronosis) enzyme is in degenerative pathway of tyrosine to fumarate --> pigment forming homogentisic acid accumulates in tissues. Autosomal recessive Findings: dark connective tissue, brown pigment sclerae, urine turns black on prolonged exposure to air. May have debilitating arthralgia (homogentisic acid toxic to cartilage)
26
What is maple syrup urine disease - mechanism - who is involved? - Presentation? - Tx?
Blocked degradation of branched amino acids due to decrease in alpha-ketoacid dehydrogenase (B1) " I Love Vermont maple syrup" Isoleucine Leucine Valine Autosomal recessive Causes severe CNS defects, intellectual disability, and death Urine smells like maple syrup Tx: restriction of isoleucine, leucine, and valine in diet, and thiamine supplementation
27
What is hartnup disease? - deficient mechanism? - what do you see clinically? - treatment?
Autosomal Recessive defect of transporter in intestine and kidneys -deficiency of neutral amino acids transporters in proximal renal tubular cells and enterocytes - deficiency of neutral AAs -- tryptophan - without tryptophan you can't make Niacin - without Niacin you get Pellagra - dermatitis, diarrhea, dementia - tx: high protein diet and nicotic acid
28
What type of infection is a patient with IL-12 receptor deficiency at highest risk for developing?
mycobacterial infections
29
What are the toxins produced by Strep pyrogens?
Streptolysin O: Hemoysis on blood agar, oxygen labile Streptolysin S: oxygen stable Streptococcal pyrogenic exotoxins: A, B, C - - erythrogenic toxins: red rash of scarlet fever - - B : necrotising fascitus - - can work as super antigens TSS
30
Which bacteria secrete enterotoxins?
``` Vibrio Cholera ETEC S. aureus Shigella Yersinia Clostridium spp ```
31
What organisms are most commonly implicated in subacute endocarditis?
Viridins strep Enterococci Staph epidermidis
32
why are ahminoglycosides ineffective against gram (+) anaerobes
require O2 in order to work | - require O2 to enter bacterial cell
33
What is considered low birth weight
less than 5 lbs 8 ozs or 1500 grams
34
What are the tumor markers for pancreatic cancer?
CA 19-A and CEA *CA 19-A is more specifi; CEA can be seen in other GI cancers
35
What diseases specifically damage the anterior horn?
Polio West Nile ALS
36
Who are the hormones that share an alpha subunit (endocrine)?
FSH LH TSH hCG
37
Who share the precursor molecule Proopiomelanocortin?
(POMC) is the abreviation for precursor ACTH MSH Lipotropins Beta-endorphin
38
What is pulsus paradox and what are its causes?
> 10mmHg systolic blood pressure drop with inspiration Causea are anything that hyperinflates the lungs: COPD, asthama and Cardiac tamponade (doesn't inflate lungs but inhibits filling)
39
What are the 4 Erythropoietin secreting tumors?
Pheochromocytoma Renal Cell carcinoma Hemangioblastoma Hepatocellular carcinoma
40
Malignancies associated with hypercalcemia
squamous cell cancers ( PTH-related peptide) Renal cell carcinoma Breast metastasis (mets to bone) Multiple Myeloma (vialocal osteolytic factors)
41
neoplasm associated with Hashimoto's Thyroiditis
lymphoma of the thyroid
42
Who utilizes tyrosine-Kinase Receptors and JAK/STAT signaling pathway?
Colony stimulating factors, prolactin, GH, and cytokines
43
Who utilizes Protein Kinase A
Gs TSH, Glucagon, PTH, and beta-adreneric receptors
44
What are the amino acids necessary for purine synthesis?
Glycine Aspartate Glutamine
45
Adrenoleukodystrophy
``` Adren = adrenal Leukodystrophy = what matter issue ``` X- linked genetic disorder Disrupts metabolism of very long chain fatty acids --> excessive buildup in nervous system, adrenal gland, testes. Progressive disease that can lead to long-term coma/death and adrenal gland crisis
46
who make up the limbic system?
Hippocamus, amygdala, fornix, mammillary bodies, cingulate gyrus 5 F's
47
Dominant parietal-temporal cortex lesion
Agraphia (inability to write) Acalcia (in ability to calculate - math) finger agnosia Left- right disorientation ( Gerstmann syndrome)
48
Lesion at basal ganglia
Tremor at rest, Chorea, athetosis (snake like movements of fingers) - huntington Resting tremor -- parkinsons
49
Lesion at paramedian pontine reticular formation
Eyes look away from side of lesion
50
Lesion at frontal eye fields
Eyes look toward lesion
51
Lesion at superior colliculi
Paralysis of upward gaze -- Parinaud's syndrome
52
lesion of non dominant parietal temporal cortex
hemispatial neglect (angora of the contralateral side of the world)
53
Acute disseminated encephalomyelitis
Post infectious Periventricular inflammation and demyelination after infection -- mealses and VZV or certain vaccines (rabies, small pox)
54
Charot Marie Tooth disease
aka Hereditary motor and sensory nueropathy progressive hereditary nerve disorders related to the defective production of proteins involved in structure and function of peripheral nerves or the myelin sheath Autosomal dominant Scoliosis and foot deformities
55
Things that cause hyperviscosity
Polycyemia vera Hyperproteinemic state (Multiple myeloma) Hereditary spherocytosis
56
Who show psomma bodies
meningioma papillary thyroid cancer serous papillary ovarian adenocarcinoma
57
Normal P-wave duration?
58
Normal PR duration?
0.12-0.2 ms
59
Normal QRS
60
normal QTc
61
normal QT
0.36- 0.44 ms
62
Olser-Weber Rendu syndrome
Aka: Hereditary Hemorhagic Telangiectasia - AD - disorder of blood vessels: branching skin lesions (telangiectasias) recurrent epistaxis (nosebleed) skin discolorations atriovenous malformations GI bleeding Hematuria
63
Polymyositis vs. dermatomyositis on muscle biopsy
Polymyositis: CD8+ with endomysial inflammation Dermatomyositis: CD4+ with perimysial inflammation both affect the proximal muscles
64
Menmonic for epidermis layers
"californians like girls in string bikinis" (FA437) ``` Stratum Corneum (keratin) Stratum Lucidum Stratum Granulosum Stratum Spinosum (desmosomes) Stratum Basale (stem cell site) ```
65
what is the skin disorder that causes an increase in the stratum spinosum and a decrease in the stratum granulosa
psoriasis
66
What is leser- Trelat sign?
FA 440 a sudden appearance of multiple seborrheic keratoses, indicating an underlying malignancy (GI or lymphoid) Seborrheic keratoses: "greasy", keratin-filled cysts (horn cysts)
67
what is cellulitis (skin)
FA 440 acute, painful, spreading infection of deeper dermis and subcutaneous tissue - S. pyrogenes or S. aureus
68
What is Erysipelas
Infection involving the upper dermis and superficial lymphatics usually caused by S. pyrogenes
69
In what skin layer is it that exotoxins from Staph aureus cause a degradation of attachments?
stratum granulosum Staphylococcal scaled skin syndrome
70
Steven- Johnson syndrome - what is it? - what is it associated with?
- Fever, Bullae formation, necrosis, sloughing of skin, high mortality rate. - typically two membranes are invovled - > 30% (greater than 30 percent) of body surface area involved - adverse drug reaction ( anti-seizure meds)
71
(micro bio FA 123) Type III secretion system and who uses it?
"injectisome" Needle-like protein appendage facilitation direct delivery of toxins form certain gram-negative bacteria Pseudomonas, Salmonella, Shigella, E.coli
72
Jarisch- Herxheimer reaction
Flu-like syndrome (fever, chills, headache, myalgia) after antibiotics are started due to killed bacteria (usually spirochetes) releasing endotoxins
73
Glucagonoma
tumor of pancreatic alpha cells -- overproduce glucagon Dermatitis (necrolytic migratory erythema) Diabetes (hyperglycemia) DVT Depression
74
DRESS syndrome
Drug Reaction with Eosinophilia and System Symptoms ( DRESS) typically occurs 2-8 weeks after exposure to high-risk drugs such as: - anticonvulsants (phenytoin, carbamazepine) - allopurinol - sulfonamides (sulfasalazine) - antibiotics ( minocycline, vancomycin) Patients typically develop fever, generalized lymphadenopathy, facial edema, diffuse skin rash, EOSINOPHILIA, and internal organ dysfunction

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