Which of the following bacterial diseases is transmitted through the bite of an infected rat flea (Xenopsylla cheopis)? MCQ with Answer and Explanation
Which of the following bacterial diseases is transmitted through the bite of an infected rat flea (Xenopsylla cheopis)?
A. Plague
B. Tetanus
C. Leprosy
D. Tuberculosis
Answer: Option A
Solution (By JKSSB Mock Tests)
Plague is a severe zoonotic bacterial disease caused by Yersinia pestis. It is primarily transmitted to humans through the bite of infected rat fleas, most commonly Xenopsylla cheopis. The disease has three main forms: bubonic (swollen lymph nodes), pneumonic (lungs), and septicemic (blood). Tuberculosis is airborne, leprosy is transmitted via prolonged close contact, and tetanus enters through deep wounds.
Explanation:
Folic acid (vitamin B₉) is reduced to tetrahydrofolate (THF), which carries one-carbon groups in amino acid and nucleotide metabolism. Biotin is for carboxylation, riboflavin for redox, thiamine for decarboxylation.
Explanation:
Convergent evolution occurs when distantly related organisms independently evolve similar traits or structures to adapt to similar ecological niches or environmental pressures. The resulting structures are called analogous organs (e.g., wings of birds and insects, eyes of octopuses and mammals). Divergent evolution is when related species evolve different traits (homologous organs). Coevolution is when two species evolve in response to each other.
Explanation:
Spermatogenesis is the production of haploid spermatozoa from spermatogonia in the seminiferous tubules. Oogenesis is egg production, gametogenesis is the general term.
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