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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

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
Q

What is the name of the disease that is deficient in homogentisate oxidase?

Presentation?

A

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)

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26
Q

What is maple syrup urine disease

  • mechanism
  • who is involved?
  • Presentation?
  • Tx?
A

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

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27
Q

What is hartnup disease?

  • deficient mechanism?
  • what do you see clinically?
  • treatment?
A

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
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28
Q

What type of infection is a patient with IL-12 receptor deficiency at highest risk for developing?

A

mycobacterial infections

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29
Q

What are the toxins produced by Strep pyrogens?

A

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
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30
Q

Which bacteria secrete enterotoxins?

A 
Vibrio Cholera
ETEC
S. aureus
Shigella
Yersinia
Clostridium spp
31
Q

What organisms are most commonly implicated in subacute endocarditis?

A

Viridins strep
Enterococci
Staph epidermidis

32
Q

why are ahminoglycosides ineffective against gram (+) anaerobes

A

require O2 in order to work

- require O2 to enter bacterial cell

33
Q

What is considered low birth weight

A

less than 5 lbs 8 ozs or 1500 grams

34
Q

What are the tumor markers for pancreatic cancer?

A

CA 19-A and CEA

*CA 19-A is more specifi; CEA can be seen in other GI cancers

35
Q

What diseases specifically damage the anterior horn?

A

Polio
West Nile
ALS

36
Q

Who are the hormones that share an alpha subunit (endocrine)?

A

FSH
LH
TSH
hCG

37
Q

Who share the precursor molecule Proopiomelanocortin?

A

(POMC) is the abreviation for precursor

ACTH
MSH
Lipotropins
Beta-endorphin

38
Q

What is pulsus paradox and what are its causes?

A

> 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
Q

What are the 4 Erythropoietin secreting tumors?

A

Pheochromocytoma
Renal Cell carcinoma
Hemangioblastoma
Hepatocellular carcinoma

40
Q

Malignancies associated with hypercalcemia

A

squamous cell cancers ( PTH-related peptide)
Renal cell carcinoma
Breast metastasis (mets to bone)
Multiple Myeloma (vialocal osteolytic factors)

41
Q

neoplasm associated with Hashimoto’s Thyroiditis

A

lymphoma of the thyroid

42
Q

Who utilizes tyrosine-Kinase Receptors and JAK/STAT signaling pathway?

A

Colony stimulating factors, prolactin, GH, and cytokines

43
Q

Who utilizes Protein Kinase A

A

Gs

TSH, Glucagon, PTH, and beta-adreneric receptors

44
Q

What are the amino acids necessary for purine synthesis?

A

Glycine
Aspartate
Glutamine

45
Q

Adrenoleukodystrophy

A 
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
Q

who make up the limbic system?

A

Hippocamus, amygdala, fornix, mammillary bodies, cingulate gyrus

5 F’s

47
Q

Dominant parietal-temporal cortex lesion

A

Agraphia (inability to write)
Acalcia (in ability to calculate - math)
finger agnosia
Left- right disorientation

( Gerstmann syndrome)

48
Q

Lesion at basal ganglia

A

Tremor at rest, Chorea, athetosis (snake like movements of fingers) - huntington

Resting tremor – parkinsons

49
Q

Lesion at paramedian pontine reticular formation

A

Eyes look away from side of lesion

50
Q

Lesion at frontal eye fields

A

Eyes look toward lesion

51
Q

Lesion at superior colliculi

A

Paralysis of upward gaze – Parinaud’s syndrome

52
Q

lesion of non dominant parietal temporal cortex

A

hemispatial neglect (angora of the contralateral side of the world)

53
Q

Acute disseminated encephalomyelitis

A

Post infectious

Periventricular inflammation and demyelination after infection – mealses and VZV or certain vaccines (rabies, small pox)

54
Q

Charot Marie Tooth disease

A

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
Q

Things that cause hyperviscosity

A

Polycyemia vera
Hyperproteinemic state (Multiple myeloma)
Hereditary spherocytosis

56
Q

Who show psomma bodies

A

meningioma
papillary thyroid cancer
serous papillary ovarian adenocarcinoma

57
Q

Normal P-wave duration?

A
58
Q

Normal PR duration?

A

0.12-0.2 ms

59
Q

Normal QRS

A
60
Q

normal QTc

A
61
Q

normal QT

A

0.36- 0.44 ms

62
Q

Olser-Weber Rendu syndrome

A

Aka: Hereditary Hemorhagic Telangiectasia

  • AD
  • disorder of blood vessels:
    branching skin lesions (telangiectasias)
    recurrent epistaxis (nosebleed)
    skin discolorations
    atriovenous malformations
    GI bleeding
    Hematuria
63
Q

Polymyositis vs. dermatomyositis on muscle biopsy

A

Polymyositis: CD8+ with endomysial inflammation

Dermatomyositis: CD4+ with perimysial inflammation

both affect the proximal muscles

64
Q

Menmonic for epidermis layers

A

“californians like girls in string bikinis” (FA437)

Stratum Corneum (keratin)
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum (desmosomes)
Stratum Basale (stem cell site)
65
Q

what is the skin disorder that causes an increase in the stratum spinosum and a decrease in the stratum granulosa

A

psoriasis

66
Q

What is leser- Trelat sign?

A

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
Q

what is cellulitis (skin)

A

FA 440

acute, painful, spreading infection of deeper dermis and subcutaneous tissue

  • S. pyrogenes or S. aureus
68
Q

What is Erysipelas

A

Infection involving the upper dermis and superficial lymphatics usually caused by S. pyrogenes

69
Q

In what skin layer is it that exotoxins from Staph aureus cause a degradation of attachments?

A

stratum granulosum

Staphylococcal scaled skin syndrome

70
Q

Steven- Johnson syndrome

  • what is it?
  • what is it associated with?
A
  • 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
Q

(micro bio FA 123) Type III secretion system and who uses it?

A

“injectisome”

Needle-like protein appendage facilitation direct delivery of toxins form certain gram-negative bacteria

Pseudomonas,
Salmonella,
Shigella,
E.coli

72
Q

Jarisch- Herxheimer reaction

A

Flu-like syndrome (fever, chills, headache, myalgia) after antibiotics are started due to killed bacteria (usually spirochetes) releasing endotoxins

73
Q

Glucagonoma

A

tumor of pancreatic alpha cells – overproduce glucagon

Dermatitis (necrolytic migratory erythema)
Diabetes (hyperglycemia)
DVT
Depression

74
Q

DRESS syndrome

A

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

USMLE (43 decks)

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