First Aid Q&A for the USMLE Step 1, 3e.PDF

PAULA BORGES, MS Stanford University Medical School Class of 2009 RACHEL BORTNICK, MPhil Medical Scientist Training Program, Year V Harvard Medical School STEVEN CHEN Johns Hopkins Univ

Assistant Clinical Professor

Chief, Section of Allergy and Clinical Immunology

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D E D I C AT I O N

To the contributors to this and future editions, who took time to share their knowledge, insight, and humor for the benefi t of students, residents, and clinicians.

and

To our families, friends, and loved ones, who supported us in the task of assembling this guide.

vi

Department of Internal Medicine

The Reading Hospital

Reading, Pa.

PAULA BORGES, MS

Stanford University Medical School

Class of 2009

RACHEL BORTNICK, MPhil

Medical Scientist Training Program, Year V

Harvard Medical School

STEVEN CHEN

Johns Hopkins University School of Medicine

Class of 2010

JOHN CHILDRESS III

University of Michigan Medical School

Class of 2010

RAGHU CHIVUKULA

Medical Scientist Training Program, Year IV

Johns Hopkins University School of Medicine

JUSTIN BRENT COHEN

Yale School of Medicine

Yale School of Medicine

ALLEN OMID EGHRARI

Johns Hopkins University School of Medicine

Class of 2009

SHARIFEH (SHERI) FARASAT

Johns Hopkins University School of Medicine Class of 2009

JAMES A FEINSTEIN, MD

Resident Department of Pediatrics Seattle Children's Hospital and Regional Medical Center

Department of Internal Medicine

University of California, Los Angeles Medical Center

MAYA ROBERTS

Yale School of Medicine and Harvard School of Public Health

Class of 2009

MARIANELI RODRIGUEZ

Medical Scientist Training Program

Johns Hopkins University School of Medicine

Stanford University School of Medicine and

University of California, Berkeley School of Public Health

Johns Hopkins University School of Medicine

KELLY VRANAS, MD

Resident Department of Internal Medicine Hospital of the University of Pennsylvania

Second Lieutenant, United States Air Force Medical Service Corps

F Edward Hébert School of Medicine

Uniformed Services University of the Health Sciences

R SHARON CHINTHRAJAH, MD

Chief Resident

Department of Internal Medicine

California Pacifi c Medical Center

San Francisco, Calif.

Assistant Professor, Pediatrics and Neurology

McKusick-Nathans Institute of Genetic Medicine

Director, Medical Genetics Residency Program

Director, Johns Hopkins University Center for Hypotonia

Johns Hopkins University School of Medicine

ALEXIS DANG, MD

Resident

Department of Orthopedic Surgery

University of California, San Francisco

GWENDOLYN J GODFREY, DO, MPH

Resident

Department of Pathology and Laboratory Medicine

University of Louisville School of Medicine

KURT E JOHNSON, PhD

Professor of Anatomy and Regenerative Biology

The George Washington University School of Medicine

WILLIAM KONIGSBERG, MD

Professor

Department of Molecular Biophysics and Biochemistry

Yale University School of Medicine

NABIL KOTBI, MD

Assistant Professor of Psychiatry

Weill Medical College of Cornell University

New York-Presbyterian Hospital

ANDREW MILLER, DO

Fellow Division of Rheumatology & Immunology Department of Medicine

Vanderbilt University Medical Center

TRACEY A MILLIGAN, MD, MS

Associate Neurologist Brigham and Women’s Hospital Instructor in Neurology Harvard Medical School

MICHAEL J PARKER, MD

Assistant Professor of Medicine Division of Pulmonary and Critical Care Medicine Beth Israel Deaconess Medical Center Senior Interactive Media Architect Center for Educational Technology Harvard Medical School

MICHAEL S RAFII, MD, PhD

Assistant Professor Department of Neurosciences University of California, San Diego School of Medicine

GEORGE A SAGI, MD

New York-Presbyterian Hospital

LAWRENCE SIEGEL, MD, MPH

Instructor Division of International Medicine & Infectious Diseases Department of Medicine

Weill Medical College of Cornell University

RICHARD S STEIN, MD

Professor Department of Medicine Vanderbilt University School of Medicine

JANIS M STOLL, MD

Resident

Departments of Internal Medicine and Pediatrics

The University of Chicago Hospitals

ANTHONY STURZU, MD

Fellow

Division of Cardiology

Massachusetts General Hospital

Harvard Medical School

EDWARD TANNER, MD

Chief Resident

Department of Gynecology and Obstetrics

Johns Hopkins University School of Medicine

PREFACE

With the second edition of First Aid Q&A for the USMLE Step 1, we continue

our commitment to providing students with the most useful and

up-to-date preparation guides for the USMLE Step 1 This new edition represents

an outstanding effort by a talented group of authors and includes the following:

䡲 Almost 1000 high-yield USMLE-style questions based on the top-rated

USMLERx Qmax Step 1 Test Bank (www.usmlerx.com).

䡲 Concise yet complete explanations to correct and incorrect answers

䡲 Questions organized by general principles and organ systems

䡲 Seven full-length test blocks simulate the actual exam experience

䡲 High-yield images, diagrams, and tables complement the questions and

answers

䡲 Organized as a perfect complement to First Aid for the USMLE Step 1

We invite you to share your thoughts and ideas to help us improve First Aid

Q&A for the USMLE Step 1 See How to Contribute, p xvii.

Louisville Tao Le

San Francisco Seth K Bechis

xiii

ACKNOWLEDGMENTS

This has been a collaborative project from the start We gratefully

acknowl-edge the thoughtful comments and advice of the medical students,

interna-tional medical graduates, and faculty who have supported the authors in the

continuing development of First Aid Q&A for the USMLE Step 1.

Additional thanks to the following for reviewing manuscript: Rachel Glaser,

MD; Niccolò Della Penna, MD; and Nathan Stitzel, MD

For support and encouragement throughout the project, we are grateful to

Thao Pham, Louise Petersen, Selina Franklin, Jonathan Kirsch, and Vikas

Bhushan Thanks to our publisher, McGraw-Hill, for the valuable assistance

of their staff For enthusiasm, support, and commitment to this challenging

project, thanks to our editor, Catherine Johnson For outstanding editorial

work, we thank Steve Freedkin, Isabel Nogueira, Mike Shelton, and Emma

D Underdown A special thanks to Rainbow Graphics for remarkable

produc-tion work

For contributions, correction, and surveys we thank Utkarsh Acharya, Achal

Achrol, Mohamad Alsabbagh, Mahyar Badrei, Judith Bellamy, Fernando

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Chua-Tuan, Horacio Contreras, Navid Eghbalieh, Felix Geissler, George Ghobrial,

Aaron Goldsmith, Ruben Gonzalez, Leo Han, Scott Herd, Alex Hunter, Atul

Jain, Katherine Kline, Michael R Krainock, Ella Leung, Kelvin Li, Milay

Luis, Elizabeth Lynn, Adrienne Ma, Eiyu Matsumoto, Francois Merle,

An-drew Nakamoto, Jessica Newbury, Jacqueline Ng, Stephanie Nguyen, Ismari

Ortiz, Puneet Panda, Gia Patel, Charles Pearlman, Laura Petrillo, Jason L

Pirga, Jessica Rabbitt, Joseph Richards, Oliver Rothschild, Abhit Singh,

Ste-phen Squires, Hugo Torres y Torres, Jennifer Turley, Ben Watters, Ben

Wein-berg, Jed Wolpaw, Vincent Yang, and Jun Yin

Louisville Tao Le

San Francisco Seth K Bechis

xv

This edition of First Aid Q&A for the USMLE Step 1 incorporates hundreds of contributions and

changes suggested by faculty and student reviewers We invite you to participate in this process We also offer paid internships in medical education and publishing ranging from three months to one year (see next page for details) Please send us your suggestions for

䡲 Corrections or enhancements to existing questions and explanations

䡲 New high-yield questions

䡲 Low-yield questions to remove

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HOW TO CONTRIBUTE

xvii

C H A P T E R 1

Behavioral Science

Q U E ST I O N S

1 A group of researchers conducted a large

doubleblind, randomized trial comparing the effi

-cacy of a new antibiotic with penicillin in

treat-ing streptococcal pneumonia The results

showed that 95% of the patients taking the new

antibiotic cleared their pneumonia, while 90%

of those taking penicillin cleared their

pneu-monia A large sample size was chosen in order

to generate a statistical power of 80% with a P

value of 21 Which of the following represents

the probability that there is a difference

be-tween the two treatment groups despite the

study’s failure to show this difference?

2 A 16-year-old boy is brought to the pediatrician

by his mother because of excessive daytime

sleepiness She states that over the past 6

months she has received numerous phone calls

from the boy’s school informing her that her

son sleeps throughout all of his afternoon

classes and is often diffi cult to arouse at the

end of class The patient reports that

occasion-ally when he wakes up in the morning he

can-not move for extended periods He says that

sometimes when he laughs at jokes or becomes

nervous before a test, he feels as if he cannot

move his legs He admits that he has even

fallen to the fl oor because of leg weakness

while laughing Which of the following is the

best choice for treating this patient?

(A) Chloral hydrate

(B) Hydroxyzine

(C) Modafi nil

(D) Prochlorperazine maleate

(E) Zolpidem

3 A 52-year-old woman is being treated by a male

psychiatrist for depression stemming from her

recent divorce Recently, the patient has been coming to her appointments dressed up and wearing expensive perfumes She has also started to fl irt with the doctor The patient’s de-meanor and appearance had initially reminded the psychiatrist of his aunt He is uncomfort-able with the patient’s new behavior patterns and tells her so She becomes very angry and storms out of the offi ce, canceling all remain-ing appointments on her way out Which of the following behaviors is an example of nega-tive transference?

(A) The doctor seeing the patient as his aunt(B) The doctor telling the patient he is un-comfortable

(C) The patient being angry with the doctor(D) The patient dressing up for appointments(E) The patient fl irting with the doctor

4 A 24-year-old woman presents to her primary

care physician because of depression and somnia for the past 6 months The patient states that she feels bad about herself almost all

in-of the time A review in-of the patient’s history shows that she has had frequent physician visits with complaints of stomachaches, headaches, and fatigue for the past 2 years Which of the following characteristics would support a diag-nosis of major depressive disorder rather than dysthymic disorder in this patient?

(A) Changes in appetite(B) Changes in sleep patterns (C) Depressed mood

(D) Fatigue/lack of energy(E) Remittance and recurrence(F) Two-year duration of symptoms

5 An infant presents to the pediatrician for a

rou-tine check-up His mother reports that he plays peek-a-boo at home, waves bye-bye, and will say

“dada.” He cannot yet drink from a cup He seemed somewhat apprehensive when the phy-sician entered the room He can lift his head when lying on his stomach, sit unassisted, and

Chapter 1: Behavioral Science • Questions 5

(A) W / (W + X + Y + Z)(B) (W + X) / (W + X + Y + Z)(C) W / (X + Y + Z)

(D) W / (X + Z)(E) (W + Y) / (W + X + Y + Z)

8 A third-year medical resident is driving home

after being on call and witnesses a car accident

He sees one person leave the car and collapse

at the side of the road He pulls over to help

The person appears to be a female in her 30s with a large laceration across her forehead She

is barely conscious Which of the following is required and/or implied under the Good Sa-maritan Law?

(A) Compensation for actions(B) Continued care until emergency services are contacted

(C) Freedom from legal action(D) Implied consent of patient in situations in which patient cannot give voluntary con-sent

(E) Use of standard procedure

9 A battery of tests is used to evaluate a

13-year-old child’s readiness to skip from seventh to ninth grade Both her mother, who has re-quested the grade change, and many of her teachers express the belief that she functions

on the intellectual level of most adults As part

of the battery, she is given an IQ test Which of the following is an appropriate IQ test to use?

(A) Iowa Test of Educational Development(B) Vineland Social Maturity Scale

(C) Wechsler Adult Intelligence Scale-Revised(D) Wechsler Intelligence Scale for Children-Revised

(E) Wide-Range Achievement Test

stand with help He has a positive Babinski’s

re-fl ex If this infant has met all his developmental

milestones appropriately, how old is he?

6 A 20-year-old man became very agitated at a

party, and as a result was brought to the

emer-gency department, where he is belligerent and

uncooperative A physical examination reveals

fever, tachycardia, horizontal nystagmus, and

hyperacusis Which of the following substances

may cause the behavioral changes and physical

fi ndings exhibited by this patient?

7 The image below is a common representation

used in studying the characteristics of a test’s

results Using the letters in the fi gure, which of

the following accurately describes the

preva-lence of the disease?

Behavioral Science

abide by her wishes because she is pated Which of the following makes this pa-tient emancipated?

emanci-(A) Age 17 years is considered an adult (B) Full-time work

(C) High school diploma(D) Living separately from her parents (E) Marriage

13 A group of oncologists is interested in

deter-mining whether a relationship exists between alcohol use and pancreatic cancer The re-searchers enroll 1,000 patients, and subjects are placed into different groups depending on their level of alcohol consumption The sub-jects are followed for 10 years; the data show

no statistical difference in the number of creatic cancers between the groups The above research is an example of which of the follow-ing kind of study?

(A) Case-control study(B) Clinical treatment trial (C) Cross-sectional study(D) Prospective cohort study(E) Retrospective cohort study

14 An 11-year-old girl is brought to the

pediatri-cian with complaints of back pain On physical examination, a right thoracic scoliotic curve is noted An x-ray fi lm indicates that the curve is

25 degrees Girls with scoliosis need to be pecially carefully watched during peak height velocity, during which the curvature can dra-matically worsen Given that peak height ve-locity occurs during a particular Tanner stage, what other physical attributes would one ex-pect to occur in the girl at the same time?(A) Elevation of the breast papilla only and no pubic hair

es-(B) Enlargement of the breast and areola with

a single contour and darker, coarse curled pubic hair

(C) Mature breast adult quantity and pattern of pubic hair that extends to the thighs

(D) Projection of the areola and papilla with separate contours and adult-type pubic hair limited to the genital area

(E) Small breast buds with elevation of breast

10 A 43-year-old woman comes to her physician’s

offi ce extremely nervous because she just

tested positive for HIV according to a newly

designed serum test Of the 1,000 patients

tested, 200 patients had HIV; the test came

back positive for 180 of them, while the

re-maining 20 tested negative Eight hundred of

the patients did not have HIV; however, the

test was positive for 40 of them The remaining

760 patients tested negative for HIV Given this

patient’s positive test, which of the following is

the probability that she does have HIV?

11 A 56-year-old man presents to his family doctor

for a regular check-up visit His past medical

history is signifi cant for long-standing

hyper-tension and coronary artery disease He had a

myocardial infarction and percutaneous

angio-plasty 1 year ago The patient initially reports

no complaints, but as his physician is heading

toward the door, the patient states with some

embarrassment that he has had problems

achieving erections since he was released from

the hospital last year He says that he has

morn-ing erections His current medications include

simvastatin and lisinopril Which of the

follow-ing is a likely cause for this man’s acquired

erectile dysfunction?

(A) Decreased interest in sexual activity

(B) Fear of another myocardial infarction

(C) Increasing age of the patient

(D) Medication side effects

(E) Physical inability after the heart attack

12 A 17-year-old girl presents to her primary care

physician with a complaint of missed menses

Tests reveal she is pregnant She returns to the

offi ce 2 weeks later asking for

recommenda-tions on obtaining an abortion She explains

that she works, lives with her husband, and is

not ready for a child She decides that she does

not want to notify anyone, and says she has

chosen not to talk with her parents for many

months Her doctor understands that he must

Chapter 1: Behavioral Science • Questions 7

18 A new serum test was recently developed to

de-tect antibodies to a certain virus in order to agnose the infection One thousand patients received the test, and while 100 people had the infection, only 80 of them tested positive Of the 900 people who did not have the infection,

di-800 tested negative and 100 tested positive

Which of the following percentages indicates the specifi city of this new test?

19 A retrospective cohort study is examining birth

complications in women with diabetes The study determines that babies are more likely to

be born large for gestational age (LGA) if the mother has diabetes The relative risk for the study is calculated to be 4 Which of the fol-lowing accurately describes this relative risk?

(A) The incidence rate of diabetes among mothers with LGA babies is 4 times that of non-LGA mothers

(B) The incidence rate of LGA among women with diabetes is 4 times that of women without diabetes

(C) The incidence rate of LGA among women without diabetes is 4 times that of women with diabetes

(D) The odds of diabetes among mothers with LGA babies is 4 times that of non-LGA mothers

(E) The odds of LGA among women with betes is 4 times that of women without dia-betes

dia-20 A 45-year-old man presents to a marriage

coun-selor at his wife’s prompting He has been

mar-and papilla mar-and sparse, straight, downy hair

on the labial base

15 A 10-year-old Hispanic boy is admitted for

bone marrow transplantation as treatment for

acute lymphocytic leukemia The doctor wants

to enroll the patient in a clinical trial for a new

pain medication, but upon arriving to discuss

the study, she fi nds that both of the patient’s

parents speak only Spanish The consent form

is in English, and the physician has a limited

knowledge of Spanish What is the physician’s

best option for obtaining consent from this

pa-tient?

(A) Exclude non-English-speaking patients

from the study

(B) Explain the study to the whole family in

Spanish, to the best of the physician’s

abil-ity

(C) Have the parents sign the English form

af-ter discussing the study via an inaf-terpreaf-ter

(D) Have the patient translate the form for his

parents

(E) Wait to obtain a translated consent form

and discuss the study via an interpreter

16 A new antihypertensive medication is being

in-vestigated in a clinical trial Investigators have

noted a decrease in blood pressure in the group

treated with the drug compared to the placebo

group While examining the study’s

partici-pants, investigators notice that the

experimen-tal group has a lower mean age What is this an

(E) Systematic error

17 A 45-year-old patient with borderline

personal-ity disorder on a psychiatry ward is told by a

staff psychiatrist to spend 2 hours in a quiet

room after violently disrupting a meeting The

next morning the psychiatrist interviews her

She complains bitterly about how the nursing

staff is so mean to her even though she is

al-ways nice to them She says she has no idea

why they locked her in the quiet room

yester-Behavioral Science

(A) Antisocial (B) Avoidant (C) Obsessive-compulsive (D) Paranoid

(E) Schizoid (F) Schizotypal

ried for 10 years and believes that his wife has

been unfaithful for the entire marriage, despite

her protests to the contrary He says that

every-one is always betraying him, and he has a

lit-any of slights, insults, and injuries that have

been perpetrated against him He is very

defen-sive with the counselor and reads an attack in

almost every statement This patient most

likely has which of the following personality

disorders?

Chapter 1: Behavioral Science • Answers 9

Answer A is incorrect Chloral hydrate is a

nonbenzodiazepine hypnotic that is used for sedation and insomnia This patient does not need help sleeping

Answer B is incorrect Hydroxyzine is a

nonse-lective antihistamine that is used in the ment of anxiety, pruritus, nausea/vomiting, se-dation, and insomnia

treat-Answer D is incorrect Prochlorperazine

maleate is a typical antipsychotic used in the treatment of nausea, vomiting, anxiety, and psychosis

Answer E is incorrect Zolpidem is a

nonben-zodiazepine hypnotic that is used in the ment of insomnia

3 The correct answer is C Transference occurs

when a patient projects feelings from his or her personal life onto a doctor; countertransfer-ence takes place when the doctor projects feel-ings onto the patient These feelings can be ei-ther positive or negative The patient’s anger at the doctor when her sexual advances are re-buffed is an example of negative transference

Answer A is incorrect The doctor being

re-minded of his aunt by this patient is an ple of countertransference

exam-Answer B is incorrect The doctor telling the

patient that he is uncomfortable is not an ample of countertransference or transference

ex-Answer D is incorrect The patient dressing

up for appointments is positive transference

1 The correct answer is B This question is

ask-ing for the b or type II error The P value in

the trial is 21, which is greater than 05 (p <

.05 is commonly accepted as statistically

signif-icant), and therefore we cannot reject the null

hypothesis Because we do not reject the null

hypothesis, there is a possibility for a type II

er-ror A type II error occurs when we state that

no difference exists when in fact one does exist

b is the probability of making a type II error; in

other words, the probability that we fail to

re-ject the null hypothesis when in fact it is false

b is related to power, calculated as 1 - b, or 1 -

0.2 = 0.80

Answer A is incorrect The P value represents

the probability of making a type I error If P

< 05, there is less than a 5% chance that the

null hypothesis was incorrectly rejected

Answer C is incorrect The fi gure 0.21 simply

represents the P value, which is greater than

.05 We therefore fail to reject the null

hypoth-esis (no difference between treatment groups)

Answer D is incorrect The fi gure 0.80

repre-sents the power of the study Power = 1 - β The

power increases when the sample size does

Answer E is incorrect The fi gure 0.90

repre-sents the percentage of patients taking

penicil-lin who were able to clear the pneumonia

Answer F is incorrect The fi gure 0.95

repre-sents the percentage of patients taking the new

antibiotic who were able to clear the

pneumo-nia

2 The correct answer is C This patient exhibits

some of the classic symptoms of narcolepsy,

in-cluding cataplexy and sleep paralysis

Cata-plexy is defi ned as brief episodes of bilateral

weakness, without alteration in consciousness

that is often brought on by strong emotions

such as laughing or fear Sleep paralysis is an

episode of partial or total paralysis that occurs

at the beginning or end of a sleep cycle

Pa-tients are often aware that they are awake, but

may suffer from frightening hallucinations

Behavioral Science

Answer F is incorrect A 2-year duration could

support either diagnosis, but is essential for the diagnosis of dysthymic disorder

5 The correct answer is B This baby is

display-ing motor, social, verbal, and cognitive skills appropriate for a 7- to 11-month-old baby A 7-

to 11-month-old baby should be able to sit alone, crawl, and stand with aid He is display-ing age-appropriate social skills such as playing peek-a-boo and displaying stranger anxiety He

is displaying age-appropriate verbal and tive skills such as saying “dada” even in a non-sensical manner Babinski refl ex ordinarily dis-appears by 12 months of age

cogni-Answer A is incorrect A 4- to 5-month-old

baby can sit with support In terms of motor development he can follow objects to midline, put his feet in his mouth, and laugh aloud

Answer C is incorrect A 12- to 15-month-old

baby can use a pincer grasp and demonstrates stranger anxiety He can turn to someone speaking to him and can gesture to objects of interest and use different sounds to convey meaning

Answer D is incorrect An 18-month-old child

can climb stairs alone and demonstrates hand preference He can stack three cubes, kick a ball, and use two-word sentences and demon-strates at least a 250-word vocabulary

Answer E is incorrect A 24-month-old child

has high activity level, can walk backward, and turn doorknobs They are often selfi sh and imi-tative They can stack 6 cubes and stand on tiptoes

6 The correct answer is F This patient has taken

phencyclidine, or PCP Patients with PCP toxication show signs of belligerence, impul-siveness, fever, psychomotor agitation, vertical and horizontal nystagmus, tachycardia, ataxia, homicidality, psychosis, and delirium On withdrawal, patients may demonstrate a recur-rence of intoxication when the PCP, which was trapped in an ionized form in the acidic gastric lumen, is reabsorbed in the alkaline du-odenum PCP users will have normal or small

in-Answer E is incorrect The patient fl irting

with the doctor is positive transference In its

most extreme form, positive transference can

take the form of sexual desire

4 The correct answer is E Mood disorders are

extremely common in primary care offi ces

Distinguishing between dysthymia and a major

depressive episode has clinical implications for

this patient This patient displays somatic

symptoms in addition to a depressed mood

Dysthymic disorder requires the presence of

two of six symptoms for at least 2 years,

includ-ing change in appetite, change in sleep

pat-terns, decreased energy, decreased self-esteem,

decreased concentration, and increased

hope-lessness Major depressive disorder is diagnosed

in patients when they have fi ve of nine

symp-toms for at least 2 weeks, including Sleep

changes, loss of Interest (anhedonia), Guilt,

Energy loss, Concentration changes, Appetite

changes, Psychomotor abnormalities, and

Sui-cidal thoughts (SIG E CAPS) Thus, major

depression is more severe, presenting with the

onset of a greater number of symptoms; more

importantly, however, this constellation of

symptoms is episodic in major depression,

whereas dysthymia does not remit and recur

Answer A is incorrect Changes in appetite

and/or weight are characteristics shared by

ma-jor depression and dysthymia Patients can

ex-hibit an increased or decreased appetite or

weight

Answer B is incorrect Changes in sleep

pat-terns are also characteristics shared by major

depression and dysthymia Patients can have

insomnia or hypersomnia

Answer C is incorrect Depressed mood is

an-other characteristic shared by the two disorders

The depressed mood tends to last longer in

pa-tients with dysthymia, although there can be

variation in their moods Diagnostic criteria for

dysthymia require that the depressed mood be

present for more days than not

Answer D is incorrect Fatigue/lack of energy

is a characteristic shared by the two disorders

Chapter 1: Behavioral Science • Answers 11

test’s validity In the chart shown, the lence can also be determined by calculating the number of true-positive plus false-negative results divided by the total number of patients

preva-Answer A is incorrect This represents

true-positive results divided by the total number of patients This would be the percent of true-positive results of all tested, but it is not used very often

Answer B is incorrect This term represents

the incidence of positive test results

Answer C is incorrect This represents

true-positive results divided by the total number of patients tested less those with true-positive re-sults, and would not be a meaningful calcula-tion

Answer D is incorrect This represents the

number of true-positive results over the total number of patients without disease This would not be a meaningful calculation

8 The correct answer is E The Good Samaritan

Law is meant to protect people (including duty medical professionals) who help others in emergency situations such as this The law dif-fers in each state, but the general concepts are the same: care providers must use standard pro-cedures Note that the law does not protect vol-unteers from gross negligence Volunteers should limit their actions to their fi eld of train-ing

off-Answer A is incorrect The Good Samaritan

Law stipulates that the care provider cannot quest or receive any compensation for his or her actions

re-Answer B is incorrect The provider should

call for help as soon as possible The law quires that once a provider assumes the role,

re-he or sre-he must stay with tre-he victim until ther help arrives, someone of equal or greater capability takes over, or it becomes unsafe to continue to give aid, not simply until help is called

fur-Answer C is incorrect The Good Samaritan

Law does not protect the volunteer from legal action The patient is free to pursue legal

pupils Death can result from a variety of

causes, including respiratory depression and

vi-olent behavior

Answer A is incorrect Patients presenting with

acute alcohol intoxication will show symptoms

of disinhibition, emotional lability, slurred

speech, ataxia, coma, and blackouts On

with-drawal, they will demonstrate a tremor,

tachy-cardia, hypertension, malaise, nausea, seizures,

delirium tremens, tremulousness, agitation,

and hallucinations

Answer B is incorrect Patients presenting with

amphetamine intoxication will display

psycho-motor agitation, impaired judgment, pupillary

dilation, hypertension, tachycardia, euphoria,

prolonged wakefulness and attention, cardiac

arrhythmias, delusions, hallucinations, and

fe-ver On withdrawal, they will show a post-use

“crash” that includes depression, lethargy,

headache, stomach cramps, hunger, and

hy-persomnolence

Answer C is incorrect Patients presenting

with acute cocaine intoxication will show

symptoms of euphoria, psychomotor agitation,

impaired judgment, tachycardia, pupillary

dila-tion, hypertension, hallucinations, paranoid

ideations, angina, and sudden cardiac death

On withdrawal, they will show a post-use

“crash” that includes severe depression,

hyper-somnolence, fatigue, malaise, and severe

psy-chological craving

Answer D is incorrect Patients presenting with

acute lysergic acid diethylamide intoxication

will display marked anxiety or depression,

delu-sions, visual hallucinations, fl ashbacks, and

pu-pillary dilation

Answer E is incorrect Patients presenting with

acute nicotine intoxication will show symptoms

of restlessness, insomnia, anxiety, and

arrhyth-mias On withdrawal, they will have symptoms

of irritability, headache, anxiety, weight gain,

craving, and tachycardia

7 The correct answer is E The prevalence is the

number of individuals with a disease in a given

population at a given time Prevalence is

esti-mated by test results but is not a measure of a

Behavioral Science

Answer B is incorrect The fi gure 24% is the

number of positive tests divided by the total number of patients

Answer D is incorrect The fi gure 90% is the

sensitivity of the new HIV test It is given by

TP / (TP + FN), where TP means true-positive and FN means false-negative, or those with the disease who test negative

Answer E is incorrect The fi gure 97% is the

negative predictive value, or the probability of not having a condition given a negative test It

is calculated by TN / (TN + FN), where TN means true-negative and FN means false-nega-tive

11 The correct answer is B There is a temporal

association between this man’s myocardial farction and his subsequent erectile dysfunc-tion (ED) The presence of morning erections indicates that the cause of this patient’s ED is psychological rather than physical The patient should be reassured that if he can tolerate climbing two fl ights of stairs, he can tolerate sexual activity

in-Answer A is incorrect It is unlikely that a

pa-tient would complain of ED if he had a creased interest in sexual activity A problem with decreased interest is more likely to be brought up by a partner or spouse

de-Answer C is incorrect Sexual desire/interest

does not decrease with age Men can have a longer refractory period and can take longer to achieve an erection as they age

Answer D is incorrect This patient’s

medica-tions are low on the sexual side effect scale While antihypertensives in general can cause impotence, angiotensin-converting enzyme in-hibitors are the least likely to do so Statins are not known to cause sexual problems

Answer E is incorrect If patients can climb

two fl ights of stairs without becoming short of breath or experiencing chest pain, limits on sexual activity are unnecessary

12 The correct answer is E Emancipation is a

le-gal defi nition through which minors become independent of their parents and are free to

recourse if the care provided is negligent and

results in injury

Answer D is incorrect As with any other

medi-cal intervention, the patient has the right to

re-fuse care from the provider

9 The correct answer is D Many different

intel-ligence quotient scales have been devised One

of the fi rst was the Stanford-Binet The Wechsler

Intelligence Scale for Children-Revised is used

to evaluate children between the ages of 6 and

16½ years The girl should be administered a

test corresponding to her age group

Answer A is incorrect The Iowa Test of

Edu-cational Development is an achievement test,

not an intelligence test It is used to evaluate

older children through the end of high school

Answer B is incorrect The Vineland Social

Maturity Scale is a test used to evaluate

adap-tive behavior It is typically used to evaluate

children with mental retardation, but its use

has been expanded to include children with

other learning disabilities

Answer C is incorrect The Wechsler Adult

In-telligence Scale-Revised is used to evaluate

those patients who are older than 16½ years

Answer E is incorrect The Wide-Range

Achievement Test is another achievement test

Unlike the Iowa tests, which are given in a

group setting to almost every child in the

United States, the Wide-Range Achievement

Test is used for individual testing

10 The correct answer is C The probability of

having a condition, given a positive test,

repre-sents the positive predictive value This is

cal-culated by TP / (TP + FP), where TP means

true-positive and FP means false-positive

There-fore, the positive predictive value is 180 / (180 +

40), or 82% As the prevalence of the disease

in-creases in a population, so does the positive

predictive value

Answer A is incorrect The fi gure 20% is the

prevalence of the disease among tested patients

(200 / 1,000)

Chapter 1: Behavioral Science • Answers 13

Study participants with a specifi c illness are given a treatment, while others with the same illness are given a different therapy or a pla-cebo Information is collected regarding the ef-

fi cacy of treatment compared with other pies or placebo

thera-Answer C is incorrect This vignette does not

exemplify a cross-sectional study These studies involve the collection of information on a dis-ease and risk factors in a population at a single point in time

Answer E is incorrect This vignette is an

ex-ample of a prospective cohort study, in which the start time for gathering information about the sample is the present day and data collec-tion extends into the future In contrast, a ret-rospective cohort study is one in which the rel-evant data are obtained from historical records (eg., medical charts), as are some or all of the outcomes being measured

14 The correct answer is B Tanner stage 3 is the

stage when most girls experience peak height velocity Peak height velocity occurs approxi-mately 1 year after the initiation of breast de-velopment

Answer A is incorrect This description

corre-sponds to Tanner stage 1

Answer C is incorrect This description

corre-sponds to Tanner stage 5

Answer D is incorrect This description

corre-sponds to Tanner stage 4

Answer E is incorrect This description

corre-sponds to Tanner stage 2

15 The correct answer is E Obtaining informed

consent from the patient means that the tient understands the risks, benefi ts, and alter-natives to the study and pertinent matters are given to them by their doctor regarding their plan of care For patients who do not speak English, the consent is translated into their lan-guage and discussed with them through an in-terpreter This allows the patient (or in this case, his parents) freedom to read and process the consent and to discuss it later While this option may not be possible for every language

pa-make medical decisions for themselves A

mi-nor, which is a legal condition defi ned by age,

can generally acquire emancipation through

court order or marriage These situations

usu-ally suggest that the minor will be fi nanciusu-ally

independent of his or her parents This patient

is married and is therefore emancipated

Answer A is incorrect While this patient has

many adult responsibilities, 18 years is the

le-gal age of consent and adulthood

Answer B is incorrect Full-time work suggests

that the patient is fi nancially independent, but

taken alone it is not proof of emancipation

Answer C is incorrect A high school diploma

does not provide emancipation Even though a

minor becomes the primary decision maker

af-ter high school graduation, he or she is not

necessarily fi nancially independent of the

par-ents

Answer D is incorrect A teenager may state

he or she has separated from the parents, but

unless the courts have approved a legal

separa-tion, merely saying she is “separated” from her

parents is not enough; legally the parents are

still fi nancially responsible for the child until

he or she turns 18

13 The correct answer is D This vignette

illus-trates a prospective cohort study This is an

ob-servational study in which a specifi c

popula-tion is identifi ed that is free of the illness at the

beginning of the study and monitored for the

development of disease over time Samples are

chosen based on the presence or absence of

risk factors (alcohol in this case), and the

inci-dence rate of a certain disease is compared

be-tween exposed and unexposed members

Answer A is incorrect Case-control studies are

also observational studies, but the sample is

chosen based on the presence (case) or

ab-sence (control) of a disease (pancreatic

can-cer) Information is then gathered regarding

prior exposures of cases and controls to certain

risk factors

Answer B is incorrect Clinical treatment trials

are examples of cohort studies; however, they

are interventional as opposed to observational

Behavioral Science

those who are selected for a study or for study subgroups

Answer E is incorrect Systematic errors result

in decreased accuracy of results

17 The correct answer is D Splitting is a belief

that people are either all good or all bad though the doctor had to approve the time in the quiet room, the patient blames only the nurses She is also displaying a tendency to-ward acting out through tantrums Splitting and acting out are two examples of immature defense mechanisms

Al-Answer A is incorrect Dissociation is a

tempo-rary, drastic change in personality, memory, consciousness, or motor behavior that is used

to avoid emotional stress This is an immature defense mechanism

Answer B is incorrect Isolation is a separation

of feelings from ideas and events This is an immature defense mechanism

Answer C is incorrect Projection is when an

unacceptable internal impulse is attributed to

an external source This is an immature fense mechanism

de-Answer E is incorrect Suppression is a

volun-tary withholding of an idea or feeling from conscious awareness This is a mature defense mechanism

18 The correct answer is D The specifi city of the

test is 89% It is calculated by dividing the negatives by the sum of the true-negatives and false-positives In the above case, the specifi city

true-is 800 / (800 + 100) The specifi city measures how well a test identifi es people who are truly well High specifi city is most important when

it means that a healthy patient might undergo unnecessary and harmful treatment because of testing positive

Answer A is incorrect The fi gure 10% simply

represents the prevalence of the disease in this select population (100 / 1000)

Answer B is incorrect The fi gure 44% is the

positive predictive value of the test It is lated by dividing true-positives by the sum of

calcu-or reasonable fcalcu-or every study, it is appropriate

in this nonemergent situation

Answer A is incorrect In a random sample

study, patients speaking another language

can-not be excluded because of language barriers

It is important that available language services

are used to include patients of all backgrounds

In addition, clinical trials should include a

broad demographic of patients

Answer B is incorrect With limited

knowl-edge of Spanish, the doctor will unlikely be

able to address all the important issues

delin-eated in the consent form

Answer C is incorrect In a nonemergent

set-ting, the best approach would allow patients

and the patient’s family to view a translated

copy of the consent and consider all their

op-tions in an unbiased manner However, the use

of an interpreter would be invaluable during

emergency setting

Answer D is incorrect The patient is not

re-sponsible for the task of translating a consent

form to his/her family This places undue

pres-sure on the patient and allows for

misinterpre-tation of the information

16 The correct answer is A A confounding error

is committed when a variable other than the

one being studied is infl uencing the results In

this study, the treatment group’s lower blood

pressure may be secondary to their younger

mean age rather than to the antihypertensive

medication A sampling bias could be involved,

although it would refer to a systematic error in

which the participants chosen for the study

where not representative of the population

from which they are drawn This would pose a

problem when attempting to generalize the

study’s results to other situations

Answer B is incorrect Random error results in

decreased precision of results

Answer C is incorrect Recall bias is a

system-atic error due to the differences in accuracy or

completeness in the memory of study subjects

Answer D is incorrect Selection bias is a

sys-tematic error resulting in differences between

Chapter 1: Behavioral Science • Answers 15

describes the relationship of the fi ndings of the study in reverse

Answer E is incorrect This choice describes

an odds ratio for a control study A control study evaluates the presence of risk fac-tors in people with and without a disease Al-though this is the opposite of a cohort study, the results are still reported in terms of disease presence with respect to risk factors; that is, the presence or absence of disease is categorized in the group with risk factors and compared to the group without risk factors The difference, however, is that odds are used rather than inci-dence The incidence rate is a percentage (eg.,

case-50 out of 100) Odds are calculated by dividing those with disease by those without (50 to 50,

or 1 to 1)

20 The correct answer is D Cluster A personality

disorders include paranoid, schizoid, and schizotypal, and patients with these disorders are often characterized as eccentric and/or weird They employ abnormal cognition (sus-piciousness), abnormal self-expression (odd speech), and abnormal relation to others (se-clusiveness) There is a genetic association with schizophrenia Patients with paranoid per-sonality disorder are not psychotic, but they are distrustful and suspicious and use projection as their main defense mechanism

Answer A is incorrect Cluster B personality

disorders include antisocial, borderline, onic, and narcissistic Patients with cluster B personality disorders are classically dramatic and unstable Patients with antisocial personal-ity disorder show a disregard for and violation

histri-of the rights histri-of others, including a proclivity for criminal behavior This is the only personality disorder with an age limit: patients must be

≥18 years old; minors with similar behavior are considered to have conduct disorder This is the only conduct disorder in which males out-number females

Answer B is incorrect Cluster C personality

disorders include avoidant, obsessive sive, and dependent, and these disorders are characterized by anxiety Patients with avoidant personality disorder are sensitive to rejection,

compul-true-positives and false-positives (80 / [80 +

100]) The positive predictive value is the

prob-ability that someone with a positive test

actu-ally does have the infection

Answer C is incorrect The fi gure 80% is the

sensitivity of the test It is calculated by

divid-ing true-positives by the sum of true-positives

and false-negatives (80 / [80 + 20]) It measures

how well a test identifi es truly ill people

Answer E is incorrect The fi gure 98% is the

negative predictive value of the test It is

calcu-lated by dividing true-negatives by the sum of

true-negatives and false-negatives (800 / [800 +

20]) The negative predictive value is the

prob-ability that a person with a negative test

actu-ally does not have the disease

19 The correct answer is B A retrospective

co-hort study includes a group of subjects who

had some condition or received some

treat-ment that is followed over time and compared

to another group (a control group) made up of

subjects who did not have this condition or

re-ceive the treatment Retrospective cohort

stud-ies are based on the presence or absence of risk

factors In this study, the risk factor is the

pres-ence of diabetes in the mothers and the

out-come would be LGA babies The incidence

rate of LGA births in women with diabetes is 4

times that in women without diabetes Relative

risk is used in cohort studies Relative risk is

de-fi ned as the incidence rate of some outcome in

those exposed to a risk factor divided by the

in-cidence rate of those not exposed This defi

ni-tion gives the factor at which the incidence

rate of LGA among women with diabetes is

larger than the incidence rate of LGA among

women without diabetes

Answer A is incorrect This choice describes

the correct type of risk analysis but describes

the relationship in reverse

Answer C is incorrect This choice reverses

the fi ndings of the study, which shows that the

incidence of LGA is four times more in women

with diabetes

Answer D is incorrect This choice incorrectly

uses odds rather than incidence rates and also

Behavioral Science

what similar to schizotypal patients, but lack the additional strange beliefs and thoughts

Answer F is incorrect Patients with

schizo-typal disorder are odd with peculiar notions, ideas of reference, and magical thinking They tend to have diffi culty with interpersonal rela-tionships and are unlikely to be in a marriage for 10 years

socially inhibited, and timid with

overwhelm-ing feeloverwhelm-ings of inadequacy

Answer C is incorrect Patients with

obsessive-compulsive personality disorder have a

preoc-cupation with order and perfectionism

Answer E is incorrect Patients with schizoid

personality disorder exhibit voluntary social

withdrawal (unlike avoidant patients) and have

limited emotional expressions They are

C H A P T E R 2

Biochemistry

Q U E ST I O N S

1 A 6-year-old boy presents to his pediatrician

with skin lesions all over his body For several

years he has been very sensitive to sunlight

Neither the boy’s parents nor his siblings have

the same skin lesions or sun sensitivity

Biop-sies of several of the boy’s lesions reveal

squamous cell carcinoma Which mutation

would one expect to see in this patient’s DNA?

(A) Methylation of the gene

(B) Missense mutation in the gene

(C) Nonsense mutation in the middle of the

gene(D) Point mutation within the enhancer region

(E) Point mutation within the operator region

(F) Point mutation within the promoter region

(G) Thymidine dimers

2 A metabolic process is pictured in the image

below Which intermediate in this process

in-hibits the rate-limiting enzyme of glycolysis

and activates the rate-limiting enzyme of fatty

Reproduced, with permission, from USMLERx.com.

3 A 32-year-old develops polyuria Her

nephrolo-gist monitors her closely on a water deprivation test, and she continues to have increased urine output A diagnosis of diabetes insipidus is made The nephrologist orders an antidiuretic hormone level and determines that it is inap-propriately elevated Which of the following is the site of pathology in this patient?

(A) Adenohypophysis (B) D1

(C) Pituitary function (D) V1

(E) V2

4 A 35-year-old man presents to the physician

with arthritic pain in both knees along with back pain He states that the pain has been present for months In an effort to obtain relief,

he has taken only aspirin, but this has been of little benefi t The patient is afebrile, and his slightly swollen knee joints are neither hot nor tender to palpation; however, the pain does re-strict his motion The cartilage of his ears ap-pears slightly darker than normal No tophi are present A urine specimen is taken for analysis

of uric acid content and turns black in the oratory while standing A defect in which of the following is the most likely underlying cause of the patient’s condition?

(A) Galactokinase(B) Homogentisic acid oxidase (C) α-Ketoacid dehydrogenase(D) Orotate phosphoribosyl transferase (E) Phenylalanine hydroxylase

5 A patient who is a carrier of sickle cell trait

presents to the clinic The single base-pair tation for sickle cell anemia destroys the MstII restriction enzyme recognition site represented

mu-by an asterisk in the image The restriction zyme-binding sites are shown as arrows on the map DNA from this patient is treated with MstII and run on an electrophoresis gel The DNA is then hybridized with a labeled probe that binds to the normal gene in the position

en-Chapter 2: Biochemistry • Questions 19

also contains one of the four bases as nucleotides The four tubes are then run on electrophoresis gel and visualized by autora-diography Which of the following laboratory techniques does this describe?

(A) Allele-specifi c oligonucleotide probe(B) Enzyme-linked immunosorbent assay (C) Northern blot

(D) Polymerase chain reaction (E) Sequencing

(F) Southern blot (G) Western blot

8 A DNA segment is treated with restriction

en-zymes, pipetted into a well of polyacrylamide gel, and subjected to an electric fi eld Next, the gel is stained with ethidium bromide and visualized under ultraviolet lights What labo-ratory technique does this describe?

(A) Enzyme-linked immunosorbent assay (B) Gel electrophoresis

(C) Northern blot(D) Polymerase chain reaction (E) Sequencing

(F) Southern blot (G) Western blot

9 Increases in intracellular calcium can be

espe-cially detrimental to the cell Therefore, cium homeostasis is very tightly regulated not only across the cell membrane but also through the additional work of sequestration in endoplasmic reticulum and mitochondria In which of the following ways does increased in-tracellular calcium concentration cause the most cell damage?

(A) Enzyme activation(B) Free radical generation(C) Increased membrane permeability(D) Inhibition of glycolysis

(E) Inhibition of oxidative phosphorylation

shown on the map In the Southern blot shown

in the image, which lane represents the

pa-tient?

1.35 Kb

A B C D E F

1.15 Kb 0.2 Kb

6 Phosphatidylcholine is a major component of

red blood cell membranes, myelin, surfactant,

and cholesterol Phosphatidylcholine is

synthe-sized through phosphorylation of choline

ob-tained from the diet or with reused choline

de-rived from phospholipid turnover De novo

synthesis requires an addition of three methyl

groups, transferred from an amino acid

With-out the turnover component, defi ciency in

which essential amino acid would make dietary

choline essential for phosphatidylcholine

7 A DNA fragment is added to four different

tubes along with DNA polymerase, a

radio-labeled primer, and the adenine, thymine,

cyto-sine, and guanine deoxynucleotides Each tube

12 A 48-year-old woman presents to a new

physi-cian because of the recent onset of fatigue, thralgias, discomfort in her right upper quad-rant, and polyuria On physical examination, her skin seems somewhat browner than would

ar-be expected Laboratory tests are remarkable for an elevated glucose level, indications of hemolysis, and increased transferrin saturation Cardiac testing shows moderate restrictive car-diomyopathy She mentions that she regularly requires blood transfusions Which of the fol-lowing is the cause of this patient’s condition?(A) Absence of the hemoglobin α chain(B) Mutation of the hemoglobin β chain(C) Mutation resulting in increased absorption

of dietary iron(D) Mutations in the gene encoding ankyrin(E) Mutations resulting in copper accumula-tion

13 A 52-year-old man with a 12-year history of

poorly controlled diabetes mellitus presents to his physician complaining of changes in his vi-sion Physical examination reveals opacities on the lens of the eye similar to those seen in the image Which enzyme most likely contributed

to this complication?

Reproduced, with permission, from Wikipedia.

(A) Adenosine deaminase (B) Aldose reductase (C) Galactose-1-phosphate uridyltransferase (D) Hexokinase

10 A scientist working in a research laboratory has

been examining different agonists of serotonin

receptor 1B (5-HT1B), a G-protein-coupled

re-ceptor Compound A has a much higher affi

n-ity for 5-HT1B than compound B Both

com-pounds have a higher affi nity for the receptor

than serotonin Which of the following

de-scribes the relationship between compound A

and compound B when considering the

gua-nine-nucleotide exchange activity of 5-HT1B?

(A) Km for the exchange reaction with

pound A is higher than that with pound B

(B) Km for the exchange reaction with

com-pound A is lower than that with comcom-pound B

(C) Km values with compounds A and B are

the same(D) The maximum reaction rate with com-

pound A is greater than that with pound B

(E) The maximum reaction rate with

pound B is greater than that with pound A

com-11 An 18-year-old woman presents to the

emer-gency department with acute onset of severe

abdominal pain She says she had a similar

at-tack 1 year earlier after taking some

barbitu-rates At that time she underwent an

explor-atory laparotomy, which revealed nothing The

patient no longer takes barbiturates but

re-cently started an extremely low-carbohydrate

and low-calorie diet She has a temperature of

37°C (98.6°F), a respiratory rate of 16/min,

and a blood pressure of 128/83 mm Hg Her

WBC count is normal Laboratory studies

re-veal a sodium level of 127 mEq/L, and

urinaly-sis shows increased porphobilinogen levels

The physician tells the patient that she has a

genetic condition involving her RBCs What

congenital disorder did the physician most

likely tell the patient she has?

(A) Acute intermittent porphyria

(B) Fanconi’s anemia

(C) Hereditary spherocytosis

(D) Porphyria cutanea tarda

(E) Sickle cell disease

Chapter 2: Biochemistry • Questions 21

(D) Steroid-responsive nephrotic syndrome

17 A 65-year-old woman develops a urinary tract

infection Urine cultures are positive for

En-terococcus faecium Treatment with

vancomy-cin is attempted but is unsuccessful Which of the following molecular changes is responsible for this patient’s vancomycin resistance?

(A) D-ala D-ala to D-ala D-lac(B) D-ala D-ala to D-ala D-leu(C) D-ala D-lac to D-ala D-ala(D) D-ala D-leu to D-ala D-ala(E) D-leu D-ala to D-ala D-ala

18 A 2-year-old boy presents to the pediatrician

with fever, facial tenderness, and a green, smelling nasal discharge The patient is diag-nosed with sinusitis, and the physician notes that he has a history of recurrent episodes of si-nusitis X-ray of the chest is ordered because of the fever; it reveals some dilated bronchi and shows the heart situated on the right side of his body A congenital disorder is diagnosed Which other fi nding would this patient be most likely to have?

foul-(A) Defective chloride transport(B) Elevated blood sugar (C) Infertility

(D) Reactive airway disease(E) Tetralogy of Fallot

(E) 3-Hydroxy-3-methylglutaryl coenzyme A

reductase

(F) Insulin-like growth factor

14 Glucose is transported into human cells by two

different families of membrane-associated

car-rier proteins: the glucose transporter facilitators

(GLUT) and the sodium-coupled glucose

transporters (SGLT) If a patient has a defect in

the non-sodium-coupled glucose transporters,

which cell line is still able to acquire glucose?

(F) Pancreatic beta cells

15 A 31-year-old white woman is trying to get

pregnant She has a niece who suffers from a

genetic disease characterized by recurrent

re-spiratory infections and pancreatic failure She

would like to assess her chances of having a

child with this disease Which of the following

laboratory techniques could be used to

deter-mine if this woman and/or her husband is a

carrier of the mutant gene?

(A) Enzyme-linked immunosorbent assay

(B) Gel electrophoresis

(C) Northern blot

(D) Polymerase chain reaction and sequencing

(E) Western blot

16 A 32-year-old woman presents to her physician

for the third time in 6 months She has been

feeling very tired and depressed, and has come

to talk about starting antidepressants She also

complains of a 4.5-kg (10-lb) weight gain over

the past 3 months During her physical

exami-nation the physician notices that she is wearing

a sweater and a coat, despite the room being at

a warm temperature Problems with the

thy-roid are suspected, and a biopsy is performed

(see image) This woman may have a human

leukocyte antigen subtype that also increases

her risk of which disease?