Question

Which drug inhibits RNA polymerase in Mycobacteria? (A) rifampin (B) ethambutol (C) isoniazid (D) amikacin (E) pyrazinamide

Short answer

Rifampin inhibits RNA polymerase in Mycobacteria.

Step-by-step solution

Understanding RNA Polymerase

RNA polymerase is an enzyme that is crucial for the transcription process in bacteria, where DNA is converted into RNA. Inhibiting this enzyme effectively prevents the bacteria from synthesizing RNA, halting their ability to produce essential proteins for survival and replication.

Evaluating the Drug Options

Let's evaluate each drug to determine its mechanism of action relative to RNA polymerase inhibition: - (A) Rifampin is known to specifically inhibit bacterial RNA polymerase. - (B) Ethambutol is known to inhibit the synthesis of the bacterial cell wall by affecting arabinogalactan. - (C) Isoniazid inhibits the synthesis of mycolic acid, a key component of the bacterial cell wall. - (D) Amikacin binds to the bacterial ribosome, preventing protein synthesis. - (E) Pyrazinamide disrupts the bacterial membrane potential and affects energy production.

Identifying the Correct Drug

Based on the mechanism of action for each drug, rifampin is the only drug that directly inhibits RNA polymerase in Mycobacteria. This makes rifampin a significant antibiotic in the treatment of infections like tuberculosis, which involve Mycobacteria.

Key concepts

Antibiotics

Antibiotics are powerful medications used to treat bacterial infections. They work by targeting specific parts of bacterial cells, which can help to kill or stop the growth of bacteria. Since bacteria can differ significantly from human cells, antibiotics can be designed to target these bacterial differences. This makes antibiotics particularly effective for treating infections without harming the host's cells.
Understanding the specific mechanism of an antibiotic is crucial for its effective and safe application. Different antibiotics have varied targets within bacterial cells. Some affect the cell wall, others target protein synthesis or DNA replication. However, misuse or overuse of antibiotics can lead to antibiotic resistance, which is a major global health concern.

Drug Mechanisms

The mechanism of action of a drug refers to the biochemical interaction through which the drug produces its effects. It's fundamental to know how a drug acts on a target organism to treat specific diseases.
Let's take rifampin as an example. It works by inhibiting RNA polymerase in bacteria, disrupting their transcription process. Understanding these mechanisms helps in designing appropriate treatment regimens, ensuring that the drugs do not harm the patient's cells.

• Rifampin targets RNA polymerase, which halts the transcription process, a crucial step in the synthesis of proteins necessary for bacterial survival.
• Ethambutol affects the bacterial cell wall construction.
• Isoniazid disrupts the formation of mycolic acid in the bacterial cell wall.
• Amikacin interferes with protein synthesis by binding to bacterial ribosomes.
• Pyrazinamide destabilizes the bacterial cell membrane and energy production.

Transcription Process

The transcription process is where the DNA of a cell is copied into RNA, specifically messenger RNA (mRNA). This is a critical step in gene expression, as mRNA conveys genetic information from DNA to the ribosome, where it guides protein synthesis.
In bacteria, RNA polymerase plays a vital role during transcription. It binds to the DNA at a specific site and synthesizes RNA by adding nucleotides complementary to the DNA template.
Inhibition of RNA polymerase, as seen with rifampin, can thwart this entire process, preventing the production of essential proteins. This makes the drug a potent treatment option for certain bacterial infections, especially when it comes to Mycobacteria like the ones causing tuberculosis.

Bacterial Protein Synthesis

Protein synthesis in bacteria involves translating the genetic code in mRNA into a sequence of amino acids to form proteins. This process is performed by the ribosomes in the cell.
There are several antibiotics that target this stage of the bacterial lifecycle. Drugs like amikacin bind to the bacterial ribosome, inhibiting protein synthesis by preventing the precise addition of amino acids to the growing protein chain.

• Translation of mRNA sequences is necessary for the production of structural proteins and enzymes critical for the bacteria’s survival.
• Disruption of protein synthesis effectively stops bacteria from growing and replicating.
• Resistance to protein synthesis inhibitors can be a major hurdle in treatment, necessitating the understanding of resistance mechanisms for adapting therapies.

Understanding these processes can help in devising strategies against antibiotic-resistant strains of bacteria.