Inhibitors Affecting Molecular Processes
The question asks to identify the cellular process inhibited by Diphtheria toxin, tetracycline, and streptomycin.
Mechanism of Action Analysis
- Diphtheria toxin functions by inactivating elongation factor 2 (eEF2) through ADP-ribosylation. This step is crucial for the movement of the ribosome along the mRNA during protein synthesis.
- Tetracycline binds to the 30S ribosomal subunit, preventing the binding of aminoacyl-tRNA to the A (acceptor) site. This directly blocks the addition of new amino acids to the growing polypeptide chain.
- Streptomycin, another antibiotic targeting the 30S ribosomal subunit, interferes with the initiation complex formation and causes misreading of the mRNA codons. This leads to the production of non-functional proteins.
Target Process Identification
All three agents—Diphtheria toxin, tetracycline, and streptomycin—specifically interfere with the process of translation, which is the synthesis of proteins from an mRNA template. They target different aspects of this process, including elongation, aminoacyl-tRNA binding, and fidelity of codon reading.
Conclusion
Therefore, Diphtheria toxin, tetracycline, and streptomycin inhibit translation.
Important Questions from Replication Transcription Splicing and Translation
Messenger RNAs (mRNAs) translate to generate polypeptides and the translation terminates at the UGA, UAG or UAA stop codons. The AGA codon acts as additional stop codon in the mitochondria. The longest possible polypeptide(s) that can be hypothetically translated in the cytosol and/or mitochondria, from the given full length mRNA sequence (36 nucleotides) is/are
5'-AACACCAUGACCCAUGUGGCGAGACGGUAGUUAAAA- 3'
- Which of the following statements about initiation of DNA replication in eukaryotes is/are true?
Match the drugs in Group I with their mechanism of action in Group II.
Group I Group II P) Paclitaxel 1) Inhibits protein translation Q) Colchicine 2) Inhibits microtubule depolymerization R) Etoposide 3) Inhibits DNA replication S) Methotrexate 4) Alkylates DNA 5) Inhibits dihydrofolate reductase 6) Inhibits microtubule polymerization Match the enzyme (Column I) with its corresponding function (Column II).
Column I Column II P. Primase 1. RNA dependent RNA synthesis Q. Reverse transcriptase 2. DNA dependent DNA synthesis R. RNA Replicase 3. RNA dependent DNA synthesis S. DNA Polymerase III 4. DNA dependent RNA synthesis Which of the following statements regarding the below mentioned mRNA sequence is/are TRUE?
5`-UGAUGAGCCUUAACCGGGAACGAAUUUAAG-3`
