The Antibiotic Rifamycin Is Selectively Toxic in Blocking Protein Synthesis

question 45

Multiple Choice

The antibiotic rifamycin is selectively toxic in blocking protein synthesis in Mycobacterium tuberculosis because _______.

• A) the antibiotic binds to the mRNA once synthesized, preventing it from participating in the initiation complex with the ribosome
• B) bacterial ribosomes are 70s whereas host ribosome are 80s, thus the antibiotic binds to the M. tuberculosis ribosome but does not bind to the eukaryotic machinery
• C) it binds preferentially to bacterial RNA polymerase rather than the eukaryotic protein, effectively halting transcription in the pathogen but not the host
• D) the drug binds to the initiator tRNA, preventing the formation of the protein synthesis initiation complex in the bacterial cell

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Definitions:

Series

Components in an electrical circuit are said to be in series if they are connected along a single path, so the same current flows through all of the components.

Inductive Reactance

The opposition to alternating current flow due to the inductance of a component or circuit, measured in ohms.

Reactive Power

Also called wattless power. Calculated by multiplying reactive voltage by reactive current. Can be produced by inductive or capacitive loads.

Inductive Reactance

The opposition an inductor provides to alternating current, directly proportional to the frequency of the current.