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WorksheetsTopic 3: Nucleophilic Acyl Substitution and Peptides
Total questions: 10
Worksheet time: 8mins
In nucleophilic acyl substitution, which of the following is considered the best leaving group?
Hydroxide ion ( OH− )
Ammonia ( NH3 )
Water ( H2O )
Chloride ion ( Cl− )
Which of the following is a common intermediate in nucleophilic acyl substitution reactions?
Carbocation
Carbanion
Tetrahedral intermediate
Radical
In non-ribosomal peptide synthesis, which enzyme is primarily responsible for the activation of amino acids?
Peptidyl transferase
Aminoacyl-tRNA synthetase
Adenylation domain
Ribosome
What is the role of the peptidyl carrier protein domain in non-ribosomal peptide synthesis?
To activate amino acids
To transfer the growing peptide chain
To catalyse peptide bond formation
To release the final peptide product
Which of the following is NOT a characteristic of non-ribosomal peptide synthesis?
Template-driven synthesis
Use of modular enzyme complexes
Incorporation of non-proteinogenic amino acids
Independent of mRNA
In non-ribosomal peptide synthesis, which domain is responsible for the cyclisation of the peptide?
Epimerisation domain
Condensation domain
Cyclisation domain
Thioesterase domain
Which of the following best describes the selectivity of non-ribosomal peptide synthetases?
They are highly selective for ribosomal amino acids only.
They can incorporate a wide variety of substrates, including non-standard amino acids.
They only synthesise peptides with even numbers of amino acids.
They are selective for nucleic acids.
Draw the product of the following reaction where the gamma phosphate is the reacting electrophilic center:
Amide bond forms from the reaction of…
Esters and ammonia
Carboxylic acid and excess ammonia
Esters and excess ammonia
Carboxylic acid and ammonia
None of these
What is the property of the species labeled Cl?
Nucleophile
Electrophile
Zwitterionic
Leaving group
Protecting group
