Govt Exams
Smallpox was declared eradicated in 1980 following intensive global vaccination campaigns, the only human virus to achieve this status.
The F pilus establishes a bridge between donor and recipient cells for plasmid transfer during bacterial conjugation.
Retroviruses like HIV use reverse transcriptase to synthesize DNA from their RNA genome for integration into host DNA.
Mycoplasma lacks a cell wall and does not stain with Gram staining but is detectable by PCR, causing atypical pneumonia.
The spike protein of SARS-CoV-2 has high affinity for ACE2 receptors, enabling efficient cellular entry and transmission.
DNA helicase breaks hydrogen bonds between base pairs to unwind the DNA double helix during replication.
Hemagglutinin (H protein) binds to sialic acid receptors on host cells, initiating viral entry in influenza.
Salmonella typhimurium is a major cause of foodborne illness from poultry, causing acute gastroenteritis.
HAV is transmitted through fecal-oral route, particularly in areas with poor sanitation and hygiene practices.
Plasmids are extrachromosomal DNA that carry antibiotic resistance genes and can be transferred between bacteria, making them primary vectors for resistance.