Q- Which one of the following drugs inhibits ribonucleotide reductase?
A- 5-Fluorouracil
B- Hydroxyurea
C- Mycophenolate
D- Ribavirin
B- Hydroxyurea- Hydroxyurea inhibits ribonucleotide reductase, blocking the conversion of ribonucleotides to deoxyribonucleotides and thereby inhibiting DNA synthesis. The other drugs act through different mechanisms.
Q- Disease prevalence can be measured by which one of the following studies?
A- Adoption study
B- Case-control study
C- Cohort study
D- Cross-sectional study
D- Cross-sectional study- A cross-sectional study measures disease prevalence by assessing a population at a single point in time. Case-control studies measure odds ratios, cohort studies measure incidence, and adoption studies evaluate genetic vs environmental effects.
Q- Which one of the following stain is most likely relevant to diagnose Cryptococcus neoformans?
A- Giemsa stain
B- India ink stain
C- Silver stain
D- Ziehl-Neelsen stain
B- India ink stain- India ink staining highlights the thick polysaccharide capsule of Cryptococcus neoformans, making it the classic diagnostic stain, especially in CSF samples.