Microbiology - MCQ Practice Questions

All three viral pathogens have demonstrated zoonotic transmission capabilities with pandemic potential, requiring surveillance and monitoring by health authorities.

Staphylococcal enterotoxins function as superantigens, directly cross-linking MHC and TCR molecules, causing massive cytokine release and toxic shock syndrome.

Reverse transcriptase synthesizes DNA from viral RNA, enabling retroviruses like HIV to establish infection by converting their genome for integration into host DNA.

Mycobacterial persistence involves multiple mechanisms: mycolic acid impedes drug entry, biofilm protects bacteria, and resistance mutations emerge under selective pressure.

Poliovirus uses IRES sequences to initiate cap-independent translation, allowing ribosome binding internally and production of polyprotein without 5' capping.

Actinobacteria, particularly Streptomyces species, form branching hyphae and mycelial networks resembling fungi, though they are prokaryotes producing many clinically useful antibiotics.

Ureaplasma urealyticum is a cell wall-deficient bacterium that produces urease enzyme and characteristically forms small translucent 'fried egg' colonies on CCDC (Chocolate Casitone Dextrose Cholesterol) medium. It's a common cause of non-gonococcal urethritis and UTIs. While Proteus also produces urease, it doesn't form fried egg colonies and has a cell wall.