Antibiotic Inhibition of Protein Synthesis
The question asks to identify the antibiotic that inhibits protein chain elongation by preventing the action of peptidyl transferase. This enzyme is crucial for forming peptide bonds between amino acids during protein synthesis.
Mechanism of Action Analysis
- Chloramphenicol: This antibiotic binds reversibly to the 50S subunit of the bacterial ribosome. It specifically inhibits the peptidyl transferase enzyme, thereby blocking the formation of peptide bonds and halting protein chain elongation.
- Rifampicin: This drug inhibits bacterial DNA-dependent RNA polymerase, preventing the initiation of RNA synthesis (transcription). It does not directly affect peptidyl transferase or protein elongation.
- Tetracycline: This antibiotic binds to the 30S ribosomal subunit and interferes with the binding of aminoacyl-tRNA to the mRNA-ribosome complex. It inhibits the initiation of protein synthesis or causes premature termination, rather than directly inhibiting peptidyl transferase.
- Bleomycin: This antibiotic functions by causing fragmentation of DNA strands. It is used primarily in cancer chemotherapy and does not inhibit protein synthesis.
Based on the mechanisms, Chloramphenicol is the antibiotic that specifically blocks protein chain elongation by preventing the action of peptidyl transferase.
Important Questions from Antibiotics and Antimicrobial Resistance
Match the antibiotics in Group I with their modes of action in Group II.
Group I Group II P) Chloramphenicol 1) Inhibits protein synthesis by acting on 30S ribosomal subunit Q) Rifampicin 2) Interferes with DNA replication by inhibiting DNA gyrase R) Tetracycline 3) Inhibits protein synthesis by acting on 50S ribosomal subunit S) Quinolone 4) Interferes with RNA polymerase activity 5) Inhibits $\beta$-lactamase activity - Which of the following statement(s) is(are) TRUE about fluoroquinolone drugs?
- A list of pathogens (Group I) and a list of anti-microbial agents (Group II) used to treat their infections are given below. Match the pathogens with the corresponding anti-microbial agents.
Group I Group II [P] Influenza A virus 1. Isoniazid [Q] Fungus 2. Amantadine [R] Plasmodium 3. Fluconazole [S] Mycobacterium 4. Artemisinin 5. Iodoquinol A bacterial culture (200 µl containing $1.8 \times 10^9$ cells) was treated with an antibiotic Z (50 µg per ml) for 4 h at 37°C. After this treatment, the culture was divided into two equal aliquots.
Set A: 100 µl was plated on Luria agar.
Set B: 100 µl was centrifuged, the cell pellet washed and plated on Luria agar.
After incubating these two plates for 24 h at 37°C, Set A plate showed no colonies, whereas the Set B plate showed $0.9 \times 10^9$ cells. This experiment showed that the antibiotic Z is
- Which of the following antimicrobial agent(s) is/are growth factor analog(s)?
