Q.30 Which one of the following is correct statement for Generalised transduction
- Occurs during the lysogenic cycle of temperate phage
- Some new viruses have both viral and bacteria DNA
- Phages penetrate bacterial cell and enter lytic cycle
- Viral DNA integrates into the DNA of the bacterium and replicates later
Phages penetrate bacterial cell and enter lytic cycle is the correct statement for generalized transduction, as it involves random packaging of bacterial DNA during the lytic phase of temperate or virulent phages.
Option Breakdown
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Occurs during the lysogenic cycle of temperate phage: Incorrect. Lysogenic cycle involves prophage integration without DNA packaging errors; transduction requires lytic packaging mistakes.
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Some new viruses have both viral and bacteria DNA: Incorrect. Transducing particles contain only bacterial DNA (replacing viral genome), not a mix.
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Phages penetrate bacterial cell and enter lytic cycle: Correct. During lysis, faulty packaging includes bacterial DNA fragments into phage heads, enabling transfer upon infecting new cells.
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Viral DNA integrates into the DNA of the bacterium and replicates later: Incorrect. This describes lysogeny/prophage formation, not transduction.
Introduction
Generalised transduction occurs when phages penetrate bacterial cell and enter lytic cycle, accidentally packaging bacterial DNA for transfer—key for bacterial genetics MCQs distinguishing from lysogenic processes. This guide explains the correct statement vs other options for NEET/microbiology exam prep.Generalized Transduction Mechanism
Phages infect bacteria, replicate lytically, and sometimes package host DNA fragments into new virions instead of phage DNA. These transducing particles infect new hosts, injecting bacterial genes for recombination. Any bacterial DNA can transfer (unlike specialized transduction).
Seen in P1, P22 phages; promotes antibiotic resistance spread.
Option Comparison Table
Statement Description Correct for Generalized Transduction? Reason Lysogenic cycle Prophage integrates No No packaging occurs Viruses with viral + bacteria DNA Mixed genomes No Pure bacterial DNA packaged Phages enter lytic cycle Lysis with faulty packaging Yes Random host DNA transfer Viral DNA integrates Lysogeny/prophage No No transduction involved Exam Tips
Identify “generalized” as lytic packaging errors vs lysogenic/specialized. Recall: lytic cycle essential for any transduction. Practice diagrams of P1 phage transduction.
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