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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. What enzyme is essential for the conversion of CO2 to HCO3-?
Carbonic anhydrase
Alzheimer disease
BPH
Negative

2. What are the primary neurotransmitters at the following sites? - Chromaffin cells of the adrenal medulla
Epinephrine
Vancomycin
Sarcoplasmic reticulum
ACE inhibitors (the - pril agents)

3. What two monosaccharides are produced when lactose is hydrolyzed?
Liver - kidney - and GI epithelium
1. Picornavirus 2. Calicivirus 3. Reovirus (Remember PCR)
Systolic interval decreases secondary to increased contractility; diastolic interval decreases secondary to an increase in heart rate.
Galactose and glucose

4. What CNs are affected if there is a lesion in x The midbrain?
GP Ib
The lack of glutathione peroxidase activity results in a decrease in NADPH production - leaving glutathione in the reduced state.
CN III and IV
Osteosarcoma

5. Which genus of dermatophytes is associated with the following sites of infection? - Nails and skin only
Aspartate and carbomoyl PO4
Epidermophyton
Spironolactone
In eukaryotes transcription occurs in the nucleus and translation in the cytoplasm.

6. What abdominal muscle contributes to the anterior layer of the rectus sheath - forms the inguinal ligament - and in men gives rise to the external spermatic fascia of the spermatic cord?
External abdominal oblique
Dilator pupillae muscle
1:1. Remember - the flow through the pulmonary circuit and the systemic circuit are equal.
ICF volume decreases when there is an increase in osmolarity and vice versa.

7. What substance is used to test platelets' response in patients with von Willebrand disease?
Blood
Clear cell
Ristocetin
SITS

8. What type of cerebral bleed is due to a rupture of a berry aneurysm in the circle of Willis?
Gastrin - releasing peptide (GRP) stimulates G cells to release Gastrin. (All G's)
Subarachnoid hematoma
Degenerates
External abdominal oblique

9. What malignant neoplasm of the skin is associated with keratin pearls?
The stapedius muscle
Squamous cell carcinoma
Anti - HAV IgG Abs are associated with immunization or a prior infection. Anti - HAV IgM is associated with acute or recent infection.
Fixed ratio (rewards set behaviors)

10. What is the term for RBC fragments?
Thoracic and sacral
Schistocytes
Class IV
2 to 4 hours

11. What disorder is associated with spider angiomas - palmar erythema - gynecomastia - testicular atrophy - encephalopathy - abnormalities in clotting factors - and portal HTN?
Chylomicrons
Filtration is greater than excretion for net reabsorption to occur.
Cirrhosis
HPV

12. What artificial sweetener must patients with PKU avoid?
Aspartame
EF- Tu and EF- Ts of the 30S ribosomal subunit
The alveoli at the apex are almost completely inflated prior to inflation - and although they are large - they receive low levels of alveolar ventilation.
HPV

13. What type of drug elimination is characterized by the following? - Elimination independent of plasma concentration; constant amount eliminated per unit time; no fixed half - life
RSV
Extravascular hemolysis if it occurs in the spleen; if in the liver - it results in hepatomegaly.
Crude mortality rate
Zero - order elimination

14. What are the three most common sites for left - sided heart embolisms to metastasize?
Cirrhosis
Pertussis toxin
Hypokalemic metabolic alkalosis occurs from vomiting because of the loss of H+ - K+ - and Cl -.
Brain - spleen - and kidney

15. Where is the action potential generated on a neuron?
alpha2- Receptors
Urinary 17- OH steroids
Thiamine and folate
Axon hillock

16. Name the antimicrobial agent whose major side effect is listed - Teratogenicity
Ascaris lumbricoides
Sorbitol (resulting in cataracts)
Metronidazole
Hirschsprung disease (aganglionic megacolon)

17. How many ATPs per glucose are produced by pyruvate dehydrogenase?
Loss of hypotonic fluid (alcohol - diabetes insipidus - dehydration)
6 ATPs (remember 2 pyruvates per glucose are produced - and 2 NADHs result from production of acetyl CoA - so 6 ATPs)
Absolutely not. Diabetics who are given a Beta- blocker for an acute chest syndrome have significantly better outcomes than those who do not.
Anticentromere Abs

18. In What tract does pain - temperature - and crude touch sensory information ascend to the postcentral gyrus of the parietal lobe?
IgM
Cefuroxime and cefaclor
Saltatory conduction
Spinothalamic tract (anterolateral system)

19. What nucleus of the hypothalamus is the satiety center - regulating food intake?
For the USMLE Step 1 the answer is no - but if the information would do more harm than good - withhold. This is very rare but it does occur.
Herpes virus
Body dysmorphic disorder
Ventromedial nucleus; lesions here result in obesity.

20. What is the most common one? - Tumor in individuals exposed to asbestos
Bronchogenic carcinoma
Arterioles have the largest drop - whereas the vena cava has the smallest pressure drop in systemic circulation.
Yes. This is done to help prevent underreporting out of fear of lawsuit. Remember that it is your duty to protect the child first - not worry about legal responsibility.
Coagulative

21. Do the following structures pick up stain from hematoxylin or eosin? - Nuclei
Separation anxiety
Hematoxylin
The concentration of plasma proteins determines effective osmolarity because capillary membranes are freely permeable to all substances except proteins.
Two major or one major and two minor

22. What is the drug of choice for hypertensive patients with a decreased renal function?
The rate of infusion
A decrease in cutaneous blood flow results from constriction of the arterioles - and decreased cutaneous blood volume results from constriction of the venous plexus.
a - Methyldopa (Guanabenz or clonidine is also used.)
The thalamus (I like to think of the thalamus as the executive secretary for the cerebral cortex. All information destined for the cortex has to go through the thalamus.)

23. What is the most common one? - Eye tumor in children
Retinoblastoma
Spearman correlation
The one start codon - AUG - in eukaryotes codes for methionine and in prokaryotes formylmethionine.
Acetaldehyde dehydrogenase

24. What is the most common complement deficiency?
Infiltrating ductal carcinoma
C2 deficiency
Lung cancer
Exposure

25. What is the physiologically active form of Ca2+?
Four Ms and a U 1. Median 2. Medial antebrachial 3. Medial pectoral 4. Medial brachial cutaneus 5. Ulnar
Mild (50-70)
IVC Remember: 1 at T8 - 2 at T10 - and 3 at T12
Free ionized Ca2+

26. Name the RNA subtype based on the following: x Found only in the nucleus of eukaryotes and functions to remove introns from mRNA
Preganglionic sympathetic neurons
snRNA
Edward syndrome (trisomy 18)
Raynaud's phenomenon

27. Do the following structures pick up stain from hematoxylin or eosin? - Collagen
Eosin
Hypothyroidism. (TSH levels must be monitored.)
The reduviid bug
Yes - it decreases fat and muscle uptake of glucose - thereby increasing blood glucose levels.

28. What is the term for how well a drug produces its desired response?
Ergosterol
Erythromycin
Efficacy
Hormone secretion for T- cell differentiation and T- cell education to recognize self from nonself

29. What Ig is the major protective factor in colostrum?
Bacillus anthracis
IgA
Transmembrane potential (an absolute number)
Cholera toxin irreversibly activates the cAMP- dependent chloride pumps of the small and large intestine - producing a large volume of chloride - rich diarrhea.

30. What syndrome is rheumatoid arthritis with pneumoconiosis?
Caplan syndrome
Methyldopa
NADPH oxidase
Hepatitis B

31. Which three aminoglycosides have vestibular toxicity?
M3 (promyelocytic leukemia)
The tsetse fly
1. Streptomycin 2. Gentamicin 3. Tobramycin
1. Fructose -6- phosphate 2. Glucose -6- phosphate 3. Glyceraldehyde -3- phosphate

32. What vitamin is necessary for the transfer of one amino group from a carbon skeleton to another?
Osteosarcoma
Eosin
PT for extrinsic and PTT for intrinsic (remember: wPeT and hPiTT - which means warfarin - extrinsic - PT; heparin - intrinsic - PTT)
Pyridoxal phosphate is derived from vitamin B6 and is needed to transfer the amino groups of one carbon skeleton to another.

33. Why should opioid analgesics be avoided for patients with head trauma?
Hepatitis C
Thyroarytenoid muscles
Sciatic nerve
Opioids cause cerebral vasodilation and can result in increased intracerebral pressure.

34. What happens to prevalence as incidence increases?
1. Cloxacillin 2. Oxacillin 3. Nafcillin 4. Dicloxacillin 5. Methicillin (CONDM)
Budd - Chiari syndrome
Ciliary ganglion. (These fibers are carried in CN III. Remember it like this:- ili - in ciliary ganglion looks like the III of CN III.)
Prevalence increases.

35. What is the amount in liters and percent body weight for the following compartments? - ICF
Autism. Head - banging - rocking - and self - injurious behaviors are also common in autism.
Succinyl CoA
28 L - 40% of body weight
Nicotinic acid - because its side effects include hyperuricemia and exacerbation of ulcers.

36. What is the term for having fantasies or dressing in female clothes for sexual arousal by heterosexual men?
Seminoma
PTH
Transvestite fetishism
The left gastric - splenic - and common hepatic arteries

37. What liver enzyme - for triglyceride synthesis - converts glycerol to glycerol -3- phosphate?
Adenosine deaminase (ADA) deficiency
Glycerol kinase
Nodular sclerosis
HMP shunt

38. Are sexually abused females more likely to have learning disabilities than the general population?
The myotatic reflex is responsible for the tension present in all resting muscle.
Thiabendazole
Yes - by three to four times. Having multiple sexual partners - being overweight - and pelvic pain and/or inflammatory disorders are also likely to be seen in sexually abused females.
Dilation of efferent arteriole

39. 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
Spearman correlation
Gain of hypotonic fluid (water intoxication or hypotonic saline)
Sucralfate
Cryptococcus neoformans

40. What is the role of the negative charge on the filtering membrane of the glomerular capillaries?
Rotavirus
Primary follicle of the cortex
Type II pneumocytes
The negative charge inhibits the filtration of protein anions.

41. What gluconeogenic mitochondrial enzyme requires biotin?
Parasympathetics (parasympathetics point - sympathetics shoot)
Inferior phrenic artery
Glossopharyngeal nerve
Pyruvate carboxylase

42. Why is there a minimal change in BP during exercise if there is a large drop in TPR?
Because the large drop in TPR is accompanied by a large increase in cardiac output - resulting in a minimal change in BP.
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).
In the PNS - myelin is produced by Schwann cells - in the CNS by oligodendrocytes.
Plasma cell

43. What Ig is associated with Ag recognition receptor on the surface of mature B cells?
IgD; IgM is also correct.
The junction where the anterior communicating and anterior cerebral arteries join. As the aneurysm expands - it compresses the fibers from the upper temporal fields of the optic chiasm - producing bitemporal inferior quadrantanopia
Hydralazine
Myasthenia gravis

44. What are the following changes seen in the luminal fluid by the time it leaves the PCT of the nephron? - Percentage of original filtered volume left in the lumen
Anti - HAV IgG Abs are associated with immunization or a prior infection. Anti - HAV IgM is associated with acute or recent infection.
IgA
Phenylalanine hydroxylase
At the end of the PCT 25% of the original volume is left

45. What malabsorption syndrome produces abdominal distention - bloating - flatulence - diarrhea - steatorrhea - and weight loss shortly after eating bread products?
Celiac sprue (gluten - sensitive enteropathy)
Enteroendocrine (EE) cells; they also secrete secretin.
Mesothelioma and bronchogenic carcinoma
Chloramphenicol

46. What three organs are responsible for peripheral conversion of T4 to T3?

47. What determines the plasma level at steady state?
Hepatocellular carcinoma is associated with hepatitis B and C infections - not with EBV.
Monosodium urate crystals
The rate of infusion
Temporal lobes

48. What enzyme is blocked by methotrexate/ trimethoprim?
Anterior nuclear group (Papez circuit of the limbic system)
Dihydrofolate reductase
Squamous cell carcinoma of the lung
Large segment deletions

49. In the classical conditioning model - when a behavior is learned - what must occur to break the probability that a response will happen?
Middle meningeal artery
Stimulus generalization must stop. (Pairing of the unconditioned stimulus and the conditioned stimulus must cease.)
Trypsin
Niacin (B3)

50. What is the most common one? - Cardiac anomaly in children
An increase in serum glucose levels
Variable ratio If it is based on time - it is an interval - and if it is based on the number of responses - it is a ratio.
PDA
Selection bias