Which amino acid’s side chain contains a nonpolar thioether group?

Which functional group contains a nitrogen atom bonded to three other atoms?

Which structural feature most directly explains cooperativity in hemoglobin but not in myoglobin?

Which of the following statements is true regarding covalent bonding in molecules?

The following is an excerpt from a recent scientific publication:“In this study, we adopted the fragment‑based drug design approach … to extract noncovalent and covalent fragments according to distinct 3D interaction modes … we recombined BTK‑focused libraries, and 23 compounds within our libraries have been validated … provides valuable resources for virtual screening of covalent and noncovalent drugs targeting similar molecular targets.” For a kinase target like BTK, what is the advantage of combining covalent and noncovalent fragments in library design?

A molecule that contains a phenyl group has what type of functional group?

The following is an excerpt from a recent scientific publication:“From a chemical point of view, proteins are by far the most structurally complex… structure and chemistry… developed and fine‑tuned over billions of years… location of each amino acid… determines its three‑dimensional shape…. precise shape … determines function.” What evolutionary rationale underlies protein structure–function specificity?

The following is an excerpt from a recent scientific publication:“Partial atomic charges are essential for an accurate description of non‑covalent interactions between drug ligands and the MOR… relative to fentanyl, the presence of the fluorine atom in the compound NFEPP alters the partial atomic charges… fentanyl has an overall larger positive charge of the amine system, which could allow stronger H‑bonding to MOR.” According to the excerpt, how does fentanyl’s protonated amine group aid receptor binding?

Which amino acid side chain is the typical nucleophile in the catalytic triad of chymotrypsin?

Which of the following amino acids has the lowest side chain pKa?