The scientist who discovered the bacterium that causes cholera was:
A. John Snow
B. Filippo Pacini
C. Louis Pasteur
D. Robert Koch
Answer: Option B
Solution (By JKSSB Mock Tests)
Filippo Pacini first observed Vibrio cholerae in 1854, but Robert Koch later independently identified it and demonstrated its role. Koch is often credited, but Pacini's discovery was earlier. John Snow linked cholera to water.
Explanation:
The placenta is the organ that attaches to the uterine wall and facilitates exchange of nutrients, oxygen, and wastes between mother and fetus. The umbilical cord connects the fetus to the placenta. The amnion forms a protective fluid-filled sac.
Explanation:
The TATA box (consensus sequence TATAAA) is a highly conserved DNA sequence located about 25-30 base pairs upstream of the transcription start site in the promoter region of many eukaryotic genes transcribed by RNA polymerase II. It is specifically recognized and bound by the TATA-binding protein (TBP), which is a crucial subunit of the general transcription factor TFIID. The binding of TBP initiates the assembly of the pre-initiation complex, including RNA polymerase II, allowing transcription to begin.
Explanation:
Dengue is transmitted by Aedes aegypti, which also spreads chikungunya, Zika, and yellow fever. Anopheles transmits malaria, Culex filariasis, tsetse sleeping sickness.
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