Practice Questions

The correct option is Synthesis of viral DNA from the viral RNA genome. Reverse transcriptase is responsible for converting the single-stranded viral RNA into double-stranded proviral DNA. Inhibiting it stops viral replication at this step.

The correct option is Treponema pallidum. Tertiary syphilis can present as neurosyphilis, causing progressive degeneration of the central nervous system (e.g., tabes dorsalis and general paresis/dementia) years or decades after the initial infection.

The correct option is Asymptomatic carriers. Many women with cervical gonococcal infections experience mild or no symptoms initially. Unaware of their infection, they do not seek treatment and continue to transmit the bacteria to sexual partners.

The correct option is Treponema pallidum. This describes late congenital syphilis. T. pallidum can cross the placenta, infecting the fetus and causing severe developmental anomalies known as the Hutchinson's triad.

The correct option is Fimbriae (pili) for firm adherence. N. gonorrhoeae possesses specialized pili that allow it to anchor securely to the mucosal epithelial cells of the genitourinary tract, preventing it from being mechanically flushed out by bodily fluids.

The correct option is Antibiotics target bacterial cellular structures absent in viruses. Antibiotics (like penicillin) disrupt bacterial-specific processes like cell wall synthesis. Herpes is a virus, which lacks these structures and replicates inside host cells, rendering antibiotics completely ineffective.

The correct option is Ectopic pregnancy. Scarring in the fallopian tubes restricts the passage of a fertilized ovum to the uterus, causing the embryo to implant within the tube (ectopic pregnancy), which is a life-threatening emergency.

The correct option is Dark-field microscopy. T. pallidum is too thin to be seen with standard bright-field microscopy and Gram stains poorly. Dark-field microscopy illuminates the live, motile spirochetes against a dark background, allowing immediate identification.

The correct option is Granulomatous lesions resulting from hypersensitivity reactions to remaining spirochetes. Gummas are soft, non-cancerous granulomatous growths that characterize tertiary syphilis. They are essentially a destructive delayed hypersensitivity immune response to localized persistent spirochete antigens.

The correct option is Latent stage. Following the disappearance of secondary stage symptoms, syphilis enters a latent phase where the patient is asymptomatic but retains the spirochetes in tissues, maintaining positive blood tests for antibodies.