When a Bacterial Cell Is Infected with a Nonlytic Bacteriophage

question 32

Multiple Choice

When a bacterial cell is infected with a nonlytic bacteriophage with Tn5 on its chromosome,the frequency of Tn5 transposition is dramatically reduced if Tn5 is already maintained on the bacterial chromosome.Why?

• A) Phage integration occurs via Tn5 homology disrupting the transposase.
• B) Tn5 transposition is inhibited by phage gene products.
• C) Tn5 on the bacterial chromosome expresses a repressor of transposition.
• D) Transposase is not expressed from Tn5 elements integrated within the bacterial chromosome.
• E) None of these

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Definitions:

Habituation

Becoming used to a stimulus and therefore paying less attention to it.

Babinski reflex

A reflex action of the foot in which the big toe extends upwards and the other toes fan out when the sole of the foot is firmly stroked, common in infants.

Regression

A return to behavior characteristic of earlier stages of development.

Moro reflex

An involuntary reflex found in infants, often referred to as the startle reflex, where the baby flings their arms out and then retracts them quickly in response to a sensation of falling or a sudden noise.