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USMLE Step 1 Prep

Subjects : health-sciences, usmle-step-1

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Cowdry type A bodies
Adult tapeworms develop in the definitive host - whereas cysticerci or larvae develop in the intermediate host.
Ependymoma
Herpesvirus
Stranger anxiety

2. What is the name of demyelination of the corticospinal tract and the dorsal column in the spinal cord due most commonly to a vitamin B12 deficiency?
CD19
Subacute combined degeneration - Which is bilateral below the level of the lesion.
The concentration of plasma proteins determines effective osmolarity because capillary membranes are freely permeable to all substances except proteins.
Iatrogenesis

3. What is the most common one? - Bone tumor
Pernicious anemia (secondary to a lack of vitamin B12 absorption)
gamma and delta chains
Metastatic
The ECF compartment always enlarges when there is a net gain in total body water and decreases when there is a loss of total body water. Hydration status is named in terms of the ECF compartment.

4. What hormone excess brings about abnormal glucose tolerance testing - impaired cardiac function - decreased body fat - increased body protein - prognathism - coarse facial features - and enlargements of the hands and feet?
Type I pneumocytes
Fixation (arrested development)
Disseminated intravascular coagulation (DIC)
Increased secretion of GH postpuberty leading to acromegaly.

5. What four branches of the brachial plexus arise prior to the first rib?
1. Dorsal scapular 2. Suprascapular 3. Long thoracic 4. Nerve to subclavius
MEN I (or Wermer syndrome)
Somatomedins
Spironolactone (binds to aldosterone receptors)

6. What type of crystals are associated with gout?
H2PO4- (dihydrogen phosphate)
Monosodium urate crystals
Negative predictive value
Rifampin

7. Is the clearance for a substance greater than or less than for inulin if it is freely filtered and secreted? If it is freely filtered and reabsorbed?
Enterokinase
Plasmodium malariae; the others are tertian.
Filtered and secreted: Cx > Cin (i.e. - PAH). Filtered and reabsorbed: Cx < Cin (i.e. - glucose) - where Cx = clearance of a substance and Cin = clearance of inulin.
Stratum granulosum

8. What is the size of a positive PPD test for the following? (Reactive) x Healthy suburban male without any medical illnesses
Increased secretion of GH postpuberty leading to acromegaly.
Granulosa/thecal cell tumor of the ovary
Climbing fibers; - they are monosynaptic input on Purkinje cells. Mossy fibers - also excitatory - are axons of all other sources and synapse on granule cells.
>15 mm

9. Why are patients with Chronic Granulomatous Disease not prone to develop infections from catalase - negative bacteria?
Stratified squamous nonkeratinized epithelium - which has cilia that beat toward the oropharynx.
Catalase - negative bacteria secrete H2O2 as a byproduct (remember - catalase breaks down H2O2) - allowing the neutrophils to use it as the substrate for the other toxic metabolites. Patients with CGD are prone to catalase - positive bacterial infect
Roth spots
H 2

10. What is the term for a schizophrenic episode lasting longer than 30 days with full return to former functioning capacity?
Brief psychotic disorder. (In schizophreniform disorder the symptoms last longer than 6 months.)
Methanol
Constipation and miosis
Sarcoidosis

11. What are the pharmacologic effects seen sexually with x Beta- Blockers?
Isoleucine - leucine - and valine
Impotence
Taenia solium
Acetyl CoA carboxylase

12. All Proteus species are...
Negative reinforcement
Cryptococcus
Left atrium
urease positive

13. What genetic defect is characterized by coarse facial features - gingival hyperplasia - macroglossia - psychomotor and growth retardation - club foot - claw hand - cardiorespiratory failure - and death in the first decade of life?
Increased CO2 - H+ - temperature - and 2 - 3- BPG levels all shift the curve to the right - thereby making the O2 easier to remove (decreased affinity) from the Hgb molecule.
I- cell disease is a result of a genetic defect affecting the phosphorylation of mannose residues.
An elevated serum osteocalcin level
Autosomal recessive

14. When does most REM sleep occur - in the first or second half of sleep?
REM sleep occurs more often in the second half of sleep. The amount of REM sleep increases as the night goes on.
Methylene blue
Tetracycline
PGE2

15. What nonmotile gram - negative - non - lactose - fermenting facultative anaerobic rod uses the human colon as its only reservoir and is transmitted by fecal - oral spread?
hCG can be detected in the blood by day 8 and in the urine by day 10.
Hepatitis C
Four high energy bonds - two from ATP in AA activation and two from GTP
Shigella

16. T cells can recognize - bind - and internalize...
MGB
Epinephrine
Phase 1
unprocessed Ags

17. What day of the menstrual cycle does ovulation take place?
RSV
Day 14
Sideroblastic anemia
The folding of an AA chain

18. Which of the following characteristics accurately describe fungi - bacteria - viruses - or parasites? - Acellular; some are enveloped; replicate within the host cell; no cell walls
90% as HCO3- - 5% as carbamino compounds - and 5% as dissolved CO2
The resistance will decrease one - sixteenth of the original resistance.
Viruses
Vitamin B6

19. How many ATPs per glucose are generated from glycolysis in RBCs?
2 ATPs - because RBCs use only anaerobic metabolism.
Solved as 30% T + 30% A = 60%; therefore - C + G = 40%; then C = 20% and G = 20% (example of Chargaff's rule)
Coxiella burnetii
positive correlation

20. Bence - Jones proteinuria
Multiple myeloma
Lung and bronchus cancer
Turner syndrome
Thiabendazole

21. What enzyme of the TCA cycle catalyzes the production of the following: x GTP
A- T are linked by 2 hydrogen bonds - C- G by 3 hydrogen bonds.
DNA ligase
Succinyl CoA synthetase
C1 through C4

22. What three substances stimulate glycogenolysis?
IDL
Short - chain fatty acids
1. Ca2+ : calmodulin ratio 2. Epinephrine 3. Glucagon
Central/neurogenic diabetes insipidus; in the nephrogenic form there is sufficient ADH available - but the renal collecting ducts are impermeable to its actions.

23. What is the DOC for the following protozoal infections? - Pneumocystis carinii pneumonia
L2 to L4 (L2 to L4 - thigh; L4 to S3 - leg)
Trimethoprim/sulfamethoxazole (TMP- SMX)
Mesonephric duct
Yes - because they both activate the BZ1- receptors - which can be reversed by flumazenil.

24. Name the most common type or cause - Childhood heart disease in the United States
Wilson disease. (Remember - patients commonly present with psychiatric manifestations and movement disorders but may be asymptomatic.)
Type I hypersensitivity (anaphylactic)
Lipid - soluble hormones are considered slow - acting hormones.
Congenital heart disease

25. What is pumped from the lumen of the ascending loop of Henle to decrease the osmolarity?
Homogentisic oxidase
NaCl is removed from the lumen to dilute the fluid leaving the loop of Henle.
Proencephalon
Cyanide

26. What is the tumor at the bifurcation of the right and left hepatic ducts?
Y - W-135 - and C and A capsular polysaccharides
Klatskin tumor
Pontocerebellar angle syndrome
HHV 6

27. What is the period between going to bed and falling asleep called?
Global aphasia
Chlamydia; gonorrhea is second (Remember - it is mandatory to report STDs to the CDC.)
Sleep latency
Doxycycline and minocycline

28. What portion of the intervertebral disk is a remnant of the notochord?
Metastatic
Extrahepatic biliary atresia
Neuroblastoma
Nucleus pulposus

29. What is the most common one? - Melanoma in dark - skinned persons
Acral - lentiginous melanoma
Nodes of Ranvier
Uroporphyrinogen I synthetase
Chromosome 11p

30. What is the most common one? - Helminth parasitic infection in the United States
Patients with unilateral cerebellar lesions fall toward the side of the lesion.
Action potential
Low average
Enterobius vermicularis

31. Inhibition of peripheral aromatic amino acid decarboxylase and increased CNS availability of L- dopa are results of what drug used in the treatment of Parkinson's disease?
Flumazenil
EF- G of the 50S subunit
DiGeorge syndrome - Which is due to a failure of the third and fourth pharyngeal pouch development. Remember - B cell deficiencies are associated with extracellular infection. T cell deficiencies are associated with intracellular infections
Carbidopa and benserazide

32. What pathway uses HMG CoA synthetase in the cytoplasm?
Cholesterol biosynthesis
Tolcapone and entacapone
Theca cell
Poxvirus replicates its DNA in the cytoplasm.

33. What CNS developmental abnormality is associated with 90% of syringomyelia?
Arnold - Chiari malformation type 2
Metastatic
The entire tubule barring the thick ascending limb
Scleroderma

34. What type of jaundice is seen in Rotor's syndrome?
G-6- PD deficiency
Stapedius muscle
Conjugated (direct) hyperbilirubinemia
Rheumatic fever

35. What is the DOC for the treatment of the late phase response in an asthmatic attack?
Papillary carcinoma of the ovary
2 to 4 hours
Corticosteroid
Brain abscess

36. What is the most common opportunistic infection of the CNS in HIV?
The lack of glutathione peroxidase activity results in a decrease in NADPH production - leaving glutathione in the reduced state.
Toxoplasmosis
Enterobius vermicularis
Acetyl CoA carboxylase

37. What disorder is associated with jaundice - white stools - and dark urine due to biliary duct occlusion secondary to incomplete recanalization?
Extrahepatic biliary atresia
Pergolide
Ipsilateral flaccid paralysis
Superior and posterior

38. Is a marker for increased bone formation.
An elevated serum osteocalcin level
Osteogenesis imperfecta
Onset of bleeding
1. H2O2 2. Superoxide 3. Hydroxyl radical 4. Myeloperoxidase 5. Hypochlorous acid

39. To What does aldose reductase convert galactose?
Farnesyl pyrophosphate (FPP)
Galactitol
CN III
Herpesvirus

40. What enzyme of the purine salvage pathway is deficient in the following? - Lesch - Nyhan syndrome
Tetracycline
Urophilia
Selegiline
HGPRT

41. Why are eukaryotes unable to perform transcription and translation at the same time like prokaryotes?
N- formyl - methionine LTB4 C5a IL-8
The vagina
Bipolar disorder (manic - depressive disorder)
In eukaryotes transcription occurs in the nucleus and translation in the cytoplasm.

42. What branch off the vertebral artery supplies x The ventrolateral two - thirds of the cervical spinal cord and the ventrolateral part of the medulla?
Anterior spinal artery
N- Acetylcysteine
Hirschsprung's disease (colonic gangliosus)
Coprophilia

43. What disease arises from the adrenal medulla - displaces and crosses the midline - metastasizes early - is the most common solid tumor - and is seen in the 2- to 4-year - old age group?
The urine becomes hypertonic because of water reabsorption in the collecting duct.
Vibrio vulnificus
The parafollicular cells of the thyroid (C cells) release calcitonin in response to hypercalcemia.
Neuroblastoma

44. Which gram - negative diplococcus ferments maltose?
1. Diarrhea 2. Dermatitis 3. Dementia 4. Death
Meningococcus (Gonococcus does not)
Roth spots - and they are seen in bacterial endocarditis.
Clearance

45. Name these cluster A personality disorders: x Socially withdrawn - seen as eccentric but happy to be alone
Schizoid
Transitional epithelium. The distal portion of the penile urethra is composed of stratified epithelium.
S2 - S3 - S4
Hypnozoite

46. The surge of what hormone induces ovulation?
Erectile dysfunction
LH
Type IV hypersensitivity reaction (delayed type because of the 48-96 hour latency)
Squamous cell carcinoma of the lung

47. What segment of the gastrointestinal tract lacks villi - has crypts - and actively transports sodium out of its lumen?
Specific rate (e.g. - men aged 55-60)
Lethal dose for 50% of drug takers (median lethal dose)
Large intestine. Water is passively removed from the lumen.
Chief cell adenoma (80%)

48. What primary acid - base disturbance is caused by an increase in alveolar ventilation (decreasing CO2 levels) resulting in the reaction shifting to the left and decreasing both H+ and HCO3- levels?
Crohn disease
Respiratory alkalosis (summary: low CO2 - low H+ - slightly low HCO3-)
Tyramine
Series circuit

49. What fungus is characterized by India ink staining of the CSF that produces colorless cells with a halo on a black background?
Decreases
Cryptococcus neoformans
Osteoarthritis
Secondary lysosome (think of the primary as inactive and secondary as active)

50. What happens to total and alveolar ventilation with x Increased rate of breathing?
Granulose cells secrete progesterone. After fertilization the granulose cells form from follicular cells.
Edrophonium
The gut rotates clockwise around the superior mesenteric artery.
With an increased rate of breathing the total ventilation is greater than the alveolar ventilation. Rapid - shallow breathing increases dead space ventilation with little change in alveolar ventilation. (This is hypoventilation).