Week 5 Practice Test 1

A 15-year-old female has never had a menstrual period. Genetic testing reveals a 45,X karyotype. Which condition is the most likely cause of her primary amenorrhea?

Turner Syndrome

A female runner experiences cessation of menses after losing significant weight and increasing exercise intensity. What type of amenorrhea is most likely present?

Secondary amenorrhea

During the menstrual cycle, a sudden increase in estradiol causes a switch from negative to positive feedback. Which hormonal event occurs next?

LH surge leading to ovulation

Which hormone predominates during the follicular phase and stimulates ovarian follicle development?

FSH

A patient is in the luteal phase of the menstrual cycle. Which ovarian structure is primarily responsible for progesterone secretion?

Corpus luteum

A woman presents with obesity, irregular menstrual cycles, infertility, and excess facial hair. Which endocrine disorder is most likely?

Polycystic Ovary Syndrome (PCOS)

A patient reports severe pelvic pain that worsens during menstruation. Laparoscopy reveals endometrial tissue on the ovaries. What condition is present?

Endometriosis

Which breast structure is directly responsible for milk production?

Alveoli

Why are postmenopausal women at increased risk for osteoporosis?

Decreased estrogen reduces osteoprotegerin (OPG), increasing osteoclast activity

Which testicular cells produce testosterone in response to LH stimulation?

Leydig cells

Which testicular cells produce inhibin to suppress FSH secretion?

Sertoli cells

Testosterone is converted into a more potent androgen responsible for virilization. Which hormone is formed?

Dihydrotestosterone (DHT)

A patient is prescribed sildenafil for erectile dysfunction. This medication enhances the effects of which molecule responsible for erection?

Nitric oxide

An older male presents with urinary frequency, urgency, and nocturia. What age-related condition is most likely responsible?

Benign Prostatic Hyperplasia (BPH)

Which gene initiates testicular development in a 46,XY embryo?

SRY gene

Shortly after birth, an infant experiences a transient increase in reproductive hormones. This phenomenon is known as what?

Minipuberty

What hypothalamic peptide increases at puberty and stimulates pulsatile GnRH secretion?

Kisspeptin

A child develops pubic and axillary hair before other signs of puberty. Which developmental process is occurring?

Adrenarche

A male has small testes, gynecomastia, infertility, and a 47,XXY karyotype. Which syndrome is present?

Klinefelter Syndrome

A 6-year-old girl develops breast buds and pubic hair. What term describes this abnormal timing of puberty?

Precocious puberty

A pregnant patient develops hypertension and proteinuria at 32 weeks gestation. What pregnancy complication is most concerning?

Preeclampsia

Which organism is the most common cause of bacterial pharyngitis and may lead to rheumatic heart disease?

Streptococcus pyogenes

Which Streptococcus pyogenes virulence factor prevents complement-mediated destruction?

M protein

A patient presents with a painful skin abscess. Culture reveals a catalase-positive organism commonly found in the nares. Which pathogen is most likely?

Staphylococcus aureus

What enzyme allows Staphylococcus aureus to neutralize reactive oxygen species produced by neutrophils?

Catalase

A strain of Staphylococcus aureus produces an enzyme that destroys penicillin. Which enzyme is responsible?

Beta-lactamase

Methicillin-resistant Staphylococcus aureus (MRSA) most commonly gains resistance through which gene?

mecA gene

Which Staphylococcus aureus exotoxin forms pores in host cell membranes, leading to cell death?

Alpha-toxin

A patient develops lung granulomas after infection with an acid-fast bacillus possessing a lipid-rich cell wall. Which pathogen is responsible?

Mycobacterium tuberculosis

Which sexually transmitted pathogen is an obligate intracellular organism that depends on host ATP production?

Chlamydia trachomatis

Which form of Chlamydia trachomatis is responsible for infecting host cells?

Elementary body

Which form of Chlamydia trachomatis replicates within host cells?

Reticulate body

A male presents with severe purulent urethritis. Gram stain reveals intracellular diplococci. Which pathogen is most likely?

Neisseria gonorrhoeae

A hospitalized patient develops severe diarrhea after antibiotic therapy. Which healthcare-associated pathogen is most likely responsible?

Clostridioides difficile

Which toxins produced by Clostridioides difficile cause pseudomembranous colitis?

Toxin A (TcdA) and Toxin B (TcdB)

A patient develops a bull's-eye rash after a tick bite and later experiences joint pain. Which pathogen is most likely responsible?

Borrelia burgdorferi

Which influenza viral protein binds host cell sialic acid receptors to initiate infection?

Hemagglutinin

Which influenza viral protein allows newly formed virions to leave infected cells?

Neuraminidase

Which HIV enzyme converts viral RNA into DNA?

Reverse transcriptase

Which HIV enzyme inserts viral DNA into the host genome?

Integrase

A patient contracts malaria after a mosquito bite. Which parasite stage enters red blood cells and produces classic cyclical symptoms?

Merozoites

A child develops shock-like inflammation 5 weeks after recovering from COVID-19. Which condition is most likely?

Multisystem Inflammatory Syndrome in Children (MIS-C)

An older adult presents with confusion, falls, and decreased appetite rather than cough and fever. Which infection should be suspected?

Community-Acquired Pneumonia (CAP)

What term describes the presence of a microorganism without tissue invasion, inflammation, or symptoms?

Colonization

What term describes microbial invasion with tissue damage and inflammatory signs?

Infection

Which pathogen category includes viruses and prions?

Nonliving pathogen particles

Which pathogen category includes bacteria?

Prokaryotes

Which pathogen category includes fungi and protozoa?

Single-celled eukaryotes

Which bacterial structure increases virulence and is particularly important in splenectomized patients?

Capsule

Which bacterial structure is primarily responsible for mobility?

Flagellum

Which bacterial structure primarily functions in attachment to host tissues?

Pili

What is the process by which bacteria reproduce by doubling their numbers?

Binary fission

What bacterial DNA structure commonly carries antibiotic resistance genes?

Plasmids

Which mechanism of antibiotic resistance involves actively pumping drugs out of the bacterial cell?

Efflux pumps

Beta-lactam antibiotics exert their effect by disrupting synthesis of what bacterial structure?

Bacterial cell wall

Which fungal cell membrane component serves as the target for many antifungal medications?

Ergosterol

Which antiviral drug class prevents influenza virions from being released from infected cells?

Neuraminidase inhibitors