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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. There is a strong ________ between IQ and academic achievement.
1. Temporal 2. Zygomatic 3. Buccal 4. Mandibular 5. Cervical (Two Zebras Bit My Clavicle.)
Oncotic pressure increases because of the removal of water.
positive correlation
Chromosome 11p

2. What chronic liver disease has a beaded appearance of the bile ducts on cholangiogram?
Antithyroglobulin and antimicrosomal Abs
Conidia
Ticlopidine or clopidogrel
Primary sclerosing cholangitis

3. What percentage of children born to HIV- positive mothers will test positive for HIV at birth?
Proencephalon diencephalon derivative
G-6- PD
External abdominal oblique
100% - with about 20% remaining positive after 1 year

4. What lecithin: sphingomyelin ratio indicates lung maturity?
Recall bias. These problems arise in retrospective studies.
Apneustic center (deep breathing place)
2.0 or greater
Diffusion rate is indirectly proportional to membrane thickness and is directly proportional to membranes surface area.

5. What enzyme found in a cholinergic synapse breaks down ACh? What are the byproducts?
Hapten (not immunogenic)
Acetylcholinesterase breaks ACh into acetate and choline (which gets resorbed by the presynaptic nerve terminal).
Ratio scale
Methicillin

6. What three criteria allow you to differentiate an ulcer from an erosion or carcinoma?
1. Less than 3 cm 2. Clean base 3. Level with the surrounding mucosa
Graves disease (Increased T4 decreases TRH and TSH through negative feedback.)
Stable
PCR

7. Can committed mentally ill patients refuse medical treatment?
Depolarization (i.e. - Na+ influx)
1. Tinea coli 2. Haustra 3. Epiploic appendages
ACE inhibitors (the - pril agents)
Yes. The only civil liberty they lose is the freedom to come and go as they please.

8. What is the limited portion of a large Ag that will actually be recognized and bound to an Ab and that contains approximately five to six amino acids or four to five hexose units?
Antigenic determinant (epitope)
Antigenic determinant (epitope). (Idiotypes bind to epitopes.)
Acetyl CoA and propionyl CoA (in odd chain fatty acids)
ATP/ADP Translocase

9. What protein is required by prokaryotic RNA polymerases to initiate transcription at the promoter region of DNA?
EBV infections resulting in infectious mononucleosis can be diagnosed by the Monospot test. (Remember - it may be negative in the first week of the illness - so retest if you have a high index of suspicion.)
Sigma factor
pK (think of it as where half is base and half is acid)
Between the renal arteries and at the bifurcation of the abdominal aorta

10. Name five causes for zero - order metabolism.
1. Sustained release 2. IV drip 3. Phenytoin 4. Alcohol 5. Aspirin toxicity
Trypsin
Thrush
Primary erectile disorder

11. What is the most common one? - Testicular tumor in men over 50 years old
Testicular lymphoma
C5a
QRS complex
Chorda tympani of CN VII

12. Which form of emphysema is associated with an alpha1- antitrypsin deficiency?
Panacinar
Negative reinforcement
Chromosome 12
Right medial longitudinal fasciculus

13. Why is O2 content depressed in anemic patients?
Anemic patients have a depressed O2 content because of the reduced concentration of Hgb in the blood. As for polycythemic patients - their O2 content is increased because of the excess Hgb concentrations.
Triazolam
Meningococcus grows on chocolate agar - and Gonococcus grows on Thayer - Martin medium.
Chromosome 3p

14. Which hepatitis B Ab indicates low transmissibility?
Subarachnoid hemorrhage
From the wall of the yolk sac
HBeAb
White muscle; short term too

15. Name the antimicrobial agent whose major side effect is listed - Hemolytic anemia
Omega -3 fatty acids
Nitrofurantoin
PRPP aminotransferase
Histidine - because of the imidazole ring found in the R group - is basic.

16. What is the term for severe and protracted vomiting resulting in linear lacerations at the gastroesophageal junction?
Hypokalemic metabolic alkalosis occurs from vomiting because of the loss of H+ - K+ - and Cl -.
Histidine
CLL (B- cell origin)
Mallory- Weiss syndrome

17. What form of hormone is described as having membrane - bound receptors that are stored in vesicles - using second messengers - and having its activity determined by free hormone levels.
Conjugated (direct) hyperbilirubinemia - a transport defect
Erythema nodosum
Water - soluble hormones are considered fast - acting hormones.
Silent

18. What AD dementia has a defect in chromosome 4 - onset between the ages of 30 and 40 - choreoathetosis - and progressive deterioration to an infantile state?
Target cell
PCR
Lung recoil - being a force to collapse the lung - increases as the lung enlarges during inspiration.
Huntington's chorea. (Death in 15-20 years - often via suicide.)

19. Which class of diuretics is used to treat metabolic acidosis - acute mountain sicknesses - and glaucoma and to aid in the elimination of acidic drug overdoses?
Carbonic anhydrase inhibitors (acetazolamide and dorzolamide)
LTB4
CN I - II - III - VI - and XII Add 1 + 1 = 2 - 1 + 2 = 3 - 1 + 2 + 3 = 6 - 1 + 2 + 3 + 6 = 12
give a warning

20. Which diuretic is used as an adrenal steroid antagonist?
Indirect pathway (Tourette syndrome for example)
C3 deficiency
Spironolactone
Albinism. Tyrosine is converted to melanin by the enzyme tyrosinase.

21. During puberty - What is the main drive for the increased GH secretion?
enveloped
Allelic exclusion. It is to ensure that one B cell produces only one Ab.
All are lactose fermenters except Yersinia and Proteus.
Increased androgen secretion at puberty drives the increased GH secretion.

22. Name the cluster B personality disorder: x Criminal behavior; lacking friends - reckless - and unable to conform to social norms
GnRH
Antisocial
Prevalence increases. (Incidence does not change.)
Giant cell tumor of the bone

23. If a mother delivers a Rho - positive baby - she should receive...
A- T are linked by 2 hydrogen bonds - C- G by 3 hydrogen bonds.
Rho-immunoglobin
Plummer - Vinson syndrome
Frontal eye field (Brodmann area 8)

24. What component of the trigeminal nuclei x Supplies the muscles of mastication?
Motor nucleus of CN V
3' end. Phosphate (PO4) is at the 5' end.
Chylomicrons
Rhombencephalon

25. Name the type of necrosis - Due to lipase activity and has a chalky white appearance
Fat necrosis
1. Epinephrine synthesis 2. Phosphatidyl choline 3. Creatine 4. Methylation of cytosine 5. N- methyl cap of mRNA
Carnitine acyl CoA transferase II
BPH

26. What small - facultative gram - negative intracellular rod's transmission is associated with unpasteurized dairy products and undulant fever?
On the superior body of the posterior wall of the uterus
Psammoma bodies
PGE (along with low oxygen tension)
Brucella

27. What catecholamine - hypersecreting tumor - a secondary cause of HTN - results in headache - diaphoresis - anxiety - tachycardia - and palpitations?
Pheochromocytoma
Achalasia. (Think Chagas disease if it presents in a person from Central or South America.)
Borderline
1:1. Remember - the flow through the pulmonary circuit and the systemic circuit are equal.

28. Do the PO2 peripheral chemoreceptors of the carotid body contribute to the normal drive for ventilation?
Lower extremity and lower trunk information travels in the dorsal spinocerebellar tract. The upper trunk and extremity information travels in the cuneocerebellar tract. (Cuneocerebellar and fasciculus cuneatus both apply to upper extremities.)
Under normal resting conditions no - but they are strongly stimulated when PO2 arterial levels decrease to 50 to 60 mm Hg - resulting in increased ventilatory drive.
The superior mesenteric vein and the splenic vein (after it receives the inferior mesenteric vein) join to form the portal vein.
P wave

29. What type of erythema do you see in x Rheumatic fever?
Paranoid
Erythema marginatum
Occipital lobe
Primary hypogonadism (postmenopausal women)

30. What vitamin is a component of the coenzyme thiamine pyrophosphate (TPP)?
Thymine (B1)
Prefrontal cortex; it is in front of the premotor area.
1. Streptomycin 2. Gentamicin 3. Tobramycin
Zanamivir and oseltamivir

31. What two Abs are used to diagnose Hashimoto's thyroiditis?
Areas 41 and 42
G-6- PD deficiency
Confounding bias
Antithyroglobulin and antimicrosomal Abs

32. Where do sperm go for maturation?
Down syndrome (trisomy 21)
Ductus epididymis - Which is lined by pseudostratified epithelium with stereocilia.
Cancer of the lung - stomach - colon - and breast
Because it is the largest vessel and has the highest velocity in systemic circulation

33. What CNS tumor arises from Rathke's pouch?
Cohort studies determine incidence and causality - not prevalence.
Craniopharyngioma
Hyperkalemia
1. Diarrhea 2. Dermatitis 3. Dementia 4. Death

34. What is the only pharyngeal muscle not innervated by CN X?
Stylopharyngeus muscle is innervated by CN IX; all other pharyngeal muscles are innervated by CN X.
Anopheles mosquito
Succinyl CoA synthetase
Onset of bleeding

35. What is the most important stimulus for the secretion of insulin?
Bipolar disorder (manic - depressive disorder)
Granulosa cell
An increase in serum glucose levels
Multiple myeloma

36. What a1- agonist is used to treat paroxysmal atrial tachycardia with hypotension?
Propofol
Metaraminol (a1 - Beta1 )
Loss of hypotonic fluid (alcohol - diabetes insipidus - dehydration)
Rho-immunoglobin

37. What enzyme is inhibited by trimethoprim?
PRPP aminotransferase
Burr cells (echinocytes)
Dihydrofolate reductase
The gut rotates clockwise around the superior mesenteric artery.

38. What is the most common one? - Cardiac pathology in patients with SLE
During a lumbar puncture the needle passes through the interlaminar space in the midline of L3- L4 - with the tip of the iliac crest in the flexed position as the landmark. Order of puncture: 1. Skin 2. Superficial fascia 3. Deep fascia 4. Supraspino
Pelvic splanchnics (They all begin with P.)
Libman - Sacks endocarditis
All

39. What are the following changes seen in the luminal fluid by the time it leaves the PCT of the nephron? - Osmolarity
Stage 2 - which accounts for approximately 45% of total sleep time - with REM occupying 20%.
Promotes systemic venous return into the chest and increases the caliber and volume of the pulmonary vessels
Histamine
300 mOsm/L

40. What is the drug of choice for early Parkinson's disease?
Receptive aphasia is due to a lesion in Brodmann areas 22 - 39 - and 40; generally the patient is unaware of the deficit.
Selegiline
Paget disease of the breast
Staphylococcus aureus

41. Describe What type of fluid is either gained or lost with the following changes in body hydration for the ECF volume - ICF volume - and body osmolarity - respectively: x ECF - increase; ICF - increase; body - decrease
Urachus
60%
1. 7- methyl guanine cap on the 5' end 2. Addition of the poly(A) tail to the 3' end 3. Removal of introns
Gain of hypotonic fluid (water intoxication or hypotonic saline)

42. What CNS tumor cells stain positive for glial fibrillary acidic protein (GFAP)?
Astrocytoma
Parasympathetic
C5- C8 deficiency
Metastatic calcification

43. What triad consists of endothelial injury - changes in laminar flow - and hypercoagulation?
NE
Gaucher disease
IgG
Virchow triad - associated with the formation of a thrombus.

44. What pneumoconiosis is associated with exposure to the following occupations or materials? - Shipyards - brake linings - insulation - and old building construction
REM sleep. Remember - awake brain in a sleeping body.
Increase (5- HT and dopamine levels do the same)
Asbestosis
Listeria monocytogenes

45. What mixed a - antagonists are used for patients with pheochromocytoma?
Foscarnet
Phentolamine and phenoxybenzamine
Homocysteine methyl transferase
PGE (along with low oxygen tension)

46. Name the most common cause - Blindness worldwide
Seminoma
Vital capacity (VC)
Chlamydia trachomatis
IF-2 of the 30S subunit

47. Is allopurinol used in the acute treatment of gout?
No - it is used in chronic treatment of gout to decrease the uric acid pools in the body.
Right coronary artery
Aschoff bodies of rheumatic fever
Prokaryotes. Polycistronic and prokaryotes both start with P.

48. What enzyme is deficient in alkaptonuria?
gamma and delta chains
Ferrochelatase
IL-5. It also stimulates eosinophil proliferation.
Homogentisic oxidase

49. Name the thalamic nucleus based on its input and output - Input from the amygdala - prefrontal cortex - and temporal lobe; output to the prefrontal lobe and the cingulated gyrus
GnRH
Poststreptococcal GN
Medial nuclear group (limbic system)
Acral - lentiginous melanoma

50. What three substrates control the enzyme PEPCK for the conversion of oxaloacetate (OAA) to pyruvate in the cytoplasm?
Aminoacyl - tRNA synthetase - which uses 2 ATPs for this reaction.
1. Cortisol (stimulates PEPCK) 2. Glucagon 3. GTP
Glucose and galactose
Secondary erectile disorder (Male erectile disorder is the same as impotence.)