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17 Cards in this Set
- Front
- Back
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What are antibiotics
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Antibiotics are bacterially or fungally produced substances that inhibit growth of other organisms
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What do the majority of antibiotics block
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Protein synthesis (translation)
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What is tRNA nucleotidyltransferase
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It is an enzyme required for the synthesis of functional tRNA's
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How does tRNA nucleotidyl transferase work
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Because the tRNA genes in the nucleus/organelles do not encode for the CCA end of a typical tRNA, the tRNA nucleotifyl transferase will use the tRNA as a primer to add the CCA end. It is different from a typical RNA polymerase because it requires a primer (tRNA).
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What is a charged tRNA
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One in which an amino acid is covalently attached to the 3' end
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What is the shine dalgarno sequence
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The Shine-Dalgarno (SD) sequence is a ribosomal binding site in prokaryotic messenger RNA, generally located upstream of the start codon AUG. The RNA sequence helps recruit the ribosome to the mRNA to initiate protein synthesis by aligning the ribosome with the start codon. The analogs sequence in eukaryotes is the kozak sequence
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What is the mnemonic for antibiotics and what do each do?
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Some try country, country destroys ears S Streptomycin Inhibits binding to P site T Tetracyclin Inhibits binding to A site C Chloramphenicol(pro) Inhbits petide bond C Cycloheximide (euk) inhibits peptide bond D Diptheria toxin (euk) inhibits translocation E Erythromycin (pro) inhibits translocation |
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Explain the specific action of each antibiotic
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Note: - streptomycin will inhibit the binding of fmet-tRNA to the P site, thus protein synthesis will not be intiated to begin with. - tetracyclin will inhibit the binding of animoacyl tRNA to the A site - petide bond formation by peptidyl transferase will be inhbited by chlorophenicol (pro) and cycloheximide (euk) - the movement from the A site to P site is inhibited by erythromycin and diphtheria toxin |
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Where is the peptide transferase activity inherent in eukaryotic vs prokaryotic ribosomes
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23s (pro), 28s (euk)
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What is the significance of the EF-G (pro) and eEF-2 (euk) elongation factors in eukaryotes and prokaryotes
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They are G-proteins and bind to GTP during translocation thus playing a critical role in the movement of mRNA to make available a new codon
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Explain the significance of ADP ribosylation by diphtheria toxin
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Diptheria toxin will ADP ribosylate a dipthamide in eEF-2 which is a protein involved in translocating peptidyl-tRNA from the A to P site on the ribosome during protein synthesis. This will inactivate eEF-2 and the cell will die because it cant make proteins |
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What is the substrate used for ADP ribosylation
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NADP+
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How is diphtheria toxin made
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By a bacteria carrying a lysogenic bacteriophage
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How do cholera toxin, E-Coli and pertussis toxi ensure widespread infection
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By targeting G proteins
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How does cholera toxin work
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ADP ribosylate Gs alpha leading to diahrrea
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How does E coli toxin work
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ADP ribosylates Gs alpha leading to travellers diahrea
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How does pertussis toxin work
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ADP ribisylates Gi alpha leading to whooping cough
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